Black-backed woodpeckers do not have a large number of predators as they are common to burned forests, which are undesirable habitats to most other species. They do, however, have certain anti-predator adaptations to better their chance of survival. The yellow crown-patch on males serves to intimidate and ward off intruders to protect themselves, their mates or young. Their predominately black coloration camouflages them well within their preferred burned habitats.
Predators have been known to prey upon both nests and adult black-backed woodpeckers. Black bears attempt to gain access to the nest by gnawing at the entrance hole which causes the inhabitants to scramble out towards the waiting bear. Other predators of adult woodpeckers include birds of prey such as Cooper's hawks. Other predators that prey on the eggs and nestlings include flying squirrels and Douglas squirrels.
Known Predators:
Anti-predator Adaptations: cryptic
Black-backed woodpeckers are medium-sized woodpeckers that have a glossy black back with white underparts. The throat, breast, and belly are white. The white sides and flanks are covered in black bars and the tail is mostly black, where only the outer feathers are white. The wings are also black with narrow white bars on them and span 12.3 to 13.4 cm. The head is glossy black and has a white stripe extending from the nasal tufts to the nape. Individuals weigh between 61 and 88 g and measure 21.5 to 24 cm in length. These woodpeckers are one of two woodpecker species that feature 3 toes instead of the usual 4. Along with three-toed woodpeckers, these birds have two toes facing forwards, but only one backwards. The most likely other species to be mistaken as black-backed woodpeckers would be three-toed woodpeckers. Three-toed woodpeckers have white barring on the back along with a white stripe of varying length behind the eye. Male black-backed woodpeckers and three-toed woodpeckers have a yellow patch of feathers on their forehead or crown.
Sexual dimorphism is present in the coloration and size of black-backed woodpeckers. Males have a yellow forehead crown patch which is the most distinguishable characteristic among males and females. Males have been found to be approximately 6 to 7% larger than females. The females however, are slightly lighter in color and have shorter bills. Juveniles are duller and have reduced or absent yellow patches.
Range mass: 61 to 88 g.
Range length: 21.5 to 24 cm.
Range wingspan: 12.3 to 13.4 cm.
Other Physical Features: endothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: male larger; male more colorful
The lifespan of black-backed woodpeckers is undetermined, but closely related three-toed woodpeckers have a life expectancy of at least 6 to 8 years.
Black-backed woodpeckers inhabit boreal and montane forests of North America where they are able to forage for insect larvae in the trunks of coniferous trees. Black-backed woodpeckers are attracted to fire-prone habitats and prefer to be near or within recently burned forests. They are found at elevations of approximately 750 m.
Average elevation: 750 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: taiga ; forest ; mountains
Black-backed woodpeckers are non-migratory birds native to North America and the Nearctic Region. The northern border of where they reside stretches from Alaska to Newfoundland and Labrador. Their range extends south through southeastern British Columbia to central California. Moving east from British Columbia their range extends to the northeast coast of the United States. They occupy this range throughout the year but vagrants sometimes wander south to Nebraska, Illinois and New Jersey.
Biogeographic Regions: nearctic (Native )
Black-backed woodpeckers are insectivores that rely on the insect communities of burned coniferous forests. They are an irruptive species that thrives in response to increased insect populations following fire. These woodpeckers prefer to forage by peeling away tree bark in order to find larvae and insects. As with most woodpeckers, this species has adapted some techniques and structural features that allow for greater foraging efficiency. They use a specific stance in order to create a greater distance between the tree trunk and their body. This allows them to accelerate a greater mass over a longer distance which produces a more forceful blow. Two structural adaptations are the loss of the hallux as well as the shortening of the distal leg bones. These give the woodpecker the ability to deliver more forceful blows, and therefore making them more efficient at foraging for food.
Some different species of larvae that black-backed woodpeckers feed upon are: white-spotted sawyers, jewel or metallic wood-boring beetles (Buprestidae family), longhorned beetles (Cerambycidae family), bark-boring beetles (Scolytidae family), and mountain pine beetles. In addition to larvae, black-backed woodpeckers have also been found to eat some plant material. They eat bark, seeds, and some fruit when there are no larvae available. This can occur after inhabiting an area for 2 to 3 years after it has been burned.
Animal Foods: insects; terrestrial non-insect arthropods
Plant Foods: wood, bark, or stems; seeds, grains, and nuts; fruit
Primary Diet: carnivore (Insectivore )
Black-backed woodpeckers prefer to reside in recently burned forests, which are inhospitable for many other species. These birds readily respond to increases in wood-boring beetle populations and thrive when this food source is abundant. Black-backed woodpeckers likely play a significant role in controlling populations of the insects they feed upon. Black-backed woodpeckers do excavate new nest cavities each breeding season, and thus they aid species that rely on others to create nesting sites.
Ecosystem Impact: creates habitat
There are no known positive effects of black-backed woodpeckers on humans.
There are no known adverse effects of black-backed woodpeckers on humans.
Black-backed woodpeckers are quite vocal and have a very sharp and distinctively fast call. The call is a single sharp note described as a 'kyik' sound. This call is between mates and is used for either territorial defense or feeding young. They also use a very unique scream-rattle-snarl call that sounds like 'wet-et-ddd-eee-yaaa' to communicate inter- and intra-specifically. Variations occur by incorporating fast or slow drumming in long, even rolls. This call is used in encounters with others and is associated with a hunched-head swinging display. Young black-backed woodpeckers make a 'gurgling' call that indicates to the parents that they are in need of food. The parents also make this call when communicating to the young that they are about to feed them.
A visual form of communication occurs when the male raises its crest. Here he fully erects his bright yellow crest in order to attract female mates or threaten animals who are too close to the nest. Like all birds, black-backed woodpeckers perceive their environment through visual, tactile, auditory and chemical stimuli.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
The conservation of black-backed woodpeckers is not of high priority. These birds have a large range and are estimated to have a large population size, thus the IUCN, the United States Migratory Bird Act, United States Federal list and CITES all consider them to be of least concern. They were also not found on COSEWIC (Committee on the Status of Endangered Wildlife in Canada).
In the state of Michigan, black-backed woodpeckers are listed as a species of special concern. Here they are seen as an S2 and G5 species. S2 refers to state rank of them being vulnerable to extirpation from the state of Michigan because of rarity and other factors which are not specified. The G5 status is the global rank where they are secure globally but that they may becoming more rare at the perimeters of their range. Since they are only of special concern they are just being monitored and no legal protection is provided. However, if numbers continue to decline they would be recommended for Threatened or Endangered Status.
Other studies have found that they can be vulnerable to local extinction because of post-fire salvage logging as well as fire suppression as they have a specialized foraging behavior and diet. Many efforts have been made to suppress fire in recent decades even though it is a natural element of many ecosystems. As these birds only occupy an area 2 to 3 years after fire, they are very vulnerable to habitat loss due to fire suppression.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: special concern
IUCN Red List of Threatened Species: least concern
Black-backed woodpeckers are monogamous. They generally only breed once per breeding season although they have been known to re-nest if their first fails. The males attract mates by raising the distinctive yellow crest feathers. Pair formation in this species is not well described, but it is believed that once a male and female form a pair they remain together year round. It also seems that once they form a pair they will rarely interact with other black-backed woodpeckers.
Mating System: monogamous
Black-backed woodpeckers have a breeding distribution that corresponds to the size and range of the boreal and mountainous coniferous forests of North America. They excavate nest cavities in trees on average 2.23 m from the ground averaging 30 cm deep. They prepare the nest in the months of April and May, before fertilization occurs in June. Clutch size ranges from 2 to 6 eggs which are incubated, primarily by the female, for 12 to 14 days. The young are altricial at birth, and will not fledge until they are 25 days old.
Breeding interval: Black-backed woodpeckers breed once yearly.
Breeding season: Black-backed woodpeckers breed from June to July.
Range eggs per season: 3 to 6.
Average time to hatching: 11 days.
Average fledging age: 25 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Both male and female black-backed woodpeckers are actively involved in the development of their young. Before fertilization occurs, they both excavate the nest which is made up of decayed wood chips that remain in the bottom of the tree cavity. A new nest is constructed every year and even though both parents contribute, the male seems to do most of the work.
Both parents, though mainly the female, participate in incubating the eggs for 11 days until they hatch. After the young hatch, the parents continue to take shifts protecting the altricial young. This period lasts up to 24 days. Both parents retrieve food for the young from the home range surrounding the nest. They bring back both the larval and adult stages of different insects. Both parents also provide protection and nest sanitation. They accomplish this by brooding within the nest and by removing the fecal sacs from the nest cavity. Fledgelings remain with the parents for a period of time to learn foraging skills. When the young reach independence, they no longer associate with the parents.
Parental Investment: altricial ; male parental care ; female parental care ; pre-fertilization (Provisioning, Protecting: Male, Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
The black-backed woodpecker occupies montane and boreal coniferous forests throughout its range. Forest species composition varies by geographic region [17]. See the Fire Regime Table for a list of plant communities in which the black-backed woodpecker may occur and information on the FIRE REGIMES associated with those communities.
Balsam fir (Abies balsamea)
Maine [24], New Hampshire [81], Vermont [51], Newfoundland [85,86,89,99], Ontario [59,112], Quebec [15] Balsam poplar (Populus balsamifera subsp. balsamifera) Alberta [83,93], Ontario [112] Black spruce (Picea mariana)Alaska [60], Maine [24], Michigan [2], Minnesota [3,26,47], Vermont [51], Alberta [36,83], Manitoba [11,109], Newfoundland [87], Northwest Territories [52], Ontario [59,112], Quebec [37,42,62,63,87,101,102], Labrador [84]
Douglas-fir (Pseudotsuga menziesii) California [28,111], Idaho [18,56,70,77,78], Montana [7,30,54,70], Oregon [12,67], Washington [6,46], Wyoming [88], British Columbia [92,94] Eastern white pine (Pinus strobus) Maine [72], Quebec [110], Michigan [2] Eastern hemlock (Tsuga canadensis) Quebec [110] Engelmann spruce (Picea engelmannii) Washington [29,46], Wyoming [68,88,97], British Columbia [94]Grand fir (A. grandis)
Oregon [12,67] Jack pine (Pinus banksiana) Michigan [2], Minnesota [3,26,47], Alberta [36,95], Ontario [106,112],Quebec [37,42,64,65,101,102], Saskatchewan [58] Jeffrey pine (P. jeffreyi) California [8,50,71] Lodgepole pine (Pinus contorta) Idaho [34,70], Montana [14], Oregon [4,19,21,67,75,98,98], Washington [29,46,98], Wyoming [16,34,88], British Columbia [53,92,94] Paper birch (Betula papyrifera) Maine [72], Michigan [2], Ontario [59] Pin cherry (Prunus pensylvanica) Maine [72] Ponderosa pine (Pinus ponderosa) California [20,28,50,71], Idaho [18,56,77,78], Montana [7,30], Oregon [12,19,67,75], South Dakota [9,10,57,73,91,107], Washington [46,74], Wyoming [91] Quaking aspen (Populus tremuloides) Maine [72], Michigan [2], South Dakota [57], Alberta [33,83,93,95], British Columbia [94], Ontario [59,112], Quebec [110], Saskatchewan [58] Red fir (A. magnifica) California [22,28,31] Red maple (Acer rubrum) Maine [72], Michigan [2] Red pine (Pinus resinosa) Michigan [2] Red spruce (Picea rubens) Maine [24],New Hampshire [81], Vermont [51] Subalpine fir (Abies lasiocarpa) Oregon [67], Washington [29,46], Wyoming [68,88,97], British Columbia [94] Sugar maple (Acer saccharum) Maine [23] Sugar pine (Pinus lambertiana) California [28] Tamarack (Larix laricina) Alaska [60], Michigan [2], Vermont [51], Manitoba [11] Washoe pine (P. washoensis)California [71]
Western larch (L. occidentalis) Montana [30,54], Oregon [12], Washington [6,46], British Columbia [92,94] White fir (Abies concolor) California [8,22,28,31,71,111], Oregon [19,75,98], Washington 103 White spruce (Picea glauca) Alaska [60], Maine [24], South Dakota [57], Alberta [33,36,83,93,95], British Columbia [94], Northwest Territories [52], Saskatchewan [58] Yellow birch (B. alleghaniensis) Maine [23] GENERAL DISTRIBUTION:
See All About Birds or NatureServe for a distribution map of the black-backed woodpecker.
The black-backed woodpecker has a fairly continuous distribution, occurring within the range of coniferous forests across northern North America. It breeds across central Canada, with populations as far north as west-central Alaska and west-central Northwest Territories. Its distribution extends east to central Labrador and throughout Newfoundland and northern New England. Populations extend south into the Great Lakes region, along the Rocky Mountains into northwestern Wyoming and south-central Idaho, and along the Pacific coast to central California. Isolated pockets of breeding occur in upstate New York and in eastern Wyoming and western South Dakota. Outside of the breeding season, individuals may move south out of the regular breeding range [17].
The black-backed woodpecker occurs in the following states and provinces (as of 2011) [66]:
United States: AK, CA, ID, MA, ME, MI, MN, MT, NH, NJ, NV, NY, OR, SD, VT, WA, WI, WY
Canada: AB, BC, LB, MB, NB, NF, NS, NT, ON, PE, QC, SK, YT
The black-backed woodpecker occupies montane and boreal conifer-dominated forests throughout its range. Forest species composition varies by geographic region [17].
Balsam fir (Abies balsamea)
Maine [24],Newfoundland [85,86,89,99], New Hampshire [81], Vermont [51], Ontario [59,112], Quebec [15] Balsam poplar (Populus balsamifera subsp. balsamifera) Alberta [83,93], Ontario [112] Black spruce (Picea mariana)Alaska [60], Maine [24], Michigan [2], Minnesota [3,26,47], Vermont [51], Alberta [36,83], Manitoba [11,109], Newfoundland [87], Northwest Territories [52], Ontario [59,112], Quebec [37,42,62,63,87,101,102], Labrador [84]
Douglas-fir (Pseudotsuga menziesii) California [28,111], Idaho [18,56,70,77,78], Montana [7,30,54,70], Oregon [12,67], Washington [6,46], Wyoming [88], British Columbia [92,94] Eastern white pine (Pinus strobus) Maine [72], Quebec [110], Michigan [2] Eastern hemlock (Tsuga canadensis) Quebec [110] Engelmann spruce (Picea engelmannii) Washington [29,46], Wyoming [68,88,97], British Columbia [94]Grand fir (A. grandis)
Oregon [12,67] Jack pine (Pinus banksiana) Michigan [2], Minnesota [3,26,47], Alberta [36,95], Ontario [106,112],Quebec [37,42,64,65,101,102], Saskatchewan [58] Jeffrey pine (P. jeffreyi) California [8,50,71] Lodgepole pine (Pinus contorta) Idaho [34,70], Montana [14], Oregon [4,19,21,67,75,98,98], Washington [29,46,98], Wyoming [16,34,88], British Columbia [53,92,94] Paper birch (Betula papyrifera) Maine [72], Michigan [2], Ontario [59] Pin cherry (Prunus pensylvanica) Maine [72] Ponderosa pine (Pinus ponderosa) California [20,28,50,71], Idaho [18,56,77,78], Montana [7,30], Oregon [12,19,67,75], South Dakota [9,10,57,73,91,107], Washington [46,74], Wyoming [91] Quaking aspen (Populus tremuloides) Maine [72], Michigan [2], South Dakota [57], Alberta [33,83,93,95], British Columbia [94], Ontario [59,112], Quebec [110], Saskatchewan [58] Red fir (A. magnifica) California [22,28,31] Red maple (Acer rubrum) Maine [72], Michigan [2] Red pine (Pinus resinosa) Michigan [2] Red spruce (Picea rubens) Maine [24],New Hampshire [81], Vermont [51] Subalpine fir (Abies lasiocarpa) Oregon [67], Washington [29,46], Wyoming [68,88,97], British Columbia [94] Sugar maple (Acer saccharum) Maine [23] Sugar pine (Pinus lambertiana) California [28] Tamarack (Larix laricina) Alaska [60], Michigan [2], Vermont [51], Manitoba [11] Washoe pine (P. washoensis)California [71]
Western larch (L. occidentalis) Montana [30,54], Oregon [12], Washington [6,46], British Columbia [92,94] White fir (Abies concolor) California [8,22,28,31,71,111], Oregon [19,75,98], Washington 103 White spruce (Picea glauca) Alaska [60], Maine [24], South Dakota [57], Alberta [33,36,83,93,95], British Columbia [94], Northwest Territories [52], Saskatchewan [58] Yellow birch (B. alleghaniensis) Maine [23]Black-backed woodpeckers are strongly associated with plant communities affected by disturbances such as fire [2,5,8,14,22,25,26,28,36,41,45,46,57,60,62,63,65,77,78,87,93,95,96,97,105,107,108] and insect outbreaks [4,9,10,11,12,15,21,67].
The diet of the black-backed woodpecker is limited, with primary food items including the larvae of mountain pine beetles, wood-boring beetles (Cerambycidae and Buprestidae), and engraver beetles (Scolytidae). Black-backed woodpeckers also feed on other insects and spiders. Plant material (e.g., wild fruits, mast, and cambium) accounts for a small proportion (<12%) of the black-backed woodpecker diet [17].
The availability of food plays a large role in the habitat selection of black-backed woodpeckers, with habitat use often linked to the presence of insect prey in both burned [64,93] and insect-killed [9,10,85] forests. Populations of primary prey are often irruptive and ephemeral, with population irruptions dictated by landscape disturbances such as fire, general forest stress, and/or other insect outbreaks [10,17,70,85]. Prey persistence is linked to local conditions such as snag availability [10] and tree moisture [35]. See Foraging habitat for information on black-backed woodpecker Foraging behavior and habitat selection.
The black-backed woodpecker is distributed from west-central Alaska east to Newfoundland and south to central California, Missesota, and New York. See All About Birds for a distribution map of the black-backed woodpecker.
The black-backed woodpecker has a fairly continuous distribution, occurring within the range of coniferous forests across northern North America. It breeds across central Canada, with populations as far north as west-central Alaska and west-central Northwest Territories. Isolated pockets of breeding occur in upstate New York and in eastern Wyoming and western South Dakota. Outside of the breeding season, individuals may move south out of the regular breeding range [17].
The black-backed woodpecker occurs in the following states and provinces (as of 2011) [66]:
United States: AK, CA, ID, MA, ME, MI, MN, MT, NH, NJ, NV, NY, OR, SD, VT, WA, WI, WY
Canada: AB, BC, LB, MB, NB, NF, NS, NT, ON, PE, QC, SK, YT
Prescribed fire: Though black-backed woodpeckers have been documented breeding [22,29] and foraging [29] in a few areas after prescribed fire, one review suggests that prescribed fire may reduce the chance of large, severe wildfires that are more likely to create suitable habitat for the black-backed woodpecker [17]. The ability of a prescribed fire to create suitable habitat for black-backed woodpeckers may depend on fire severity, size, and the creation of snags for nesting or foraging.
Postfire salvage logging: Postfire salvage logging is generally considered to have negative effects on black-backed woodpeckers [17]. Standing dead trees provide important nesting and foraging habitat for black-backed woodpeckers. Studies suggest that black-backed woodpeckers may avoid [33,58], occur at lower abundance [13,30,45,84], or have fewer nests [32,41,77] in areas salvage-logged after fire compared to burned areas that were not logged. However, one study found no significant difference in nest survival between logged and unlogged burned areas, though more nests were found in the unlogged areas [77].
The impacts of salvage logging on black-backed woodpecker abundance were studied after mixed-severity wildfire in northeastern Alberta in 2 forest types: black spruce and jack pine forests and quaking aspen and white spruce forests. Using data pooled from the 1st summer and winter and the 2nd summer after fire, black-backed woodpecker abundance was lower in salvage-logged areas compared to unsalvaged areas in both forest types (P<0.05). There was some seasonality and a temporal aspect to results; salvage logging had a negative effect on abundance the 1st summer (P=0.037) and winter (P=0.059) after fire, but it had no effect the 2nd summer [45].
Data from 3 studies suggest that the impacts of salvage-logging logging on black-backed woodpeckers may vary with logging intensity. Based on data from 13,337 independent sample points in northern Idaho and Montana, the probability of detecting a black-backed woodpecker decreased incrementally with an increase in intensity of recent postfire timber harvesting (P=0.06). Intensity was categorized as "none" (no evidence based on the presence of recent tree stumps); "light harvest" (evidence of levels of tree removal associated with minor selective harvesting through moderate shelter wood cutting); or "heavy harvest" (evidence of extensive tree removal associated with a seed-tree cut or clearcut) [40]. One study monitored the response of cavity-nesting birds to 3 snag density treatments (high=37-80 snags/ha; medium=15-35 snags/ha; low=0-12 snags/ha) during 2 breeding seasons 4 and 5 years after stand-replacing wildfire and logging in Douglas-fir and ponderosa pine forests in Washington. The abundance of black-backed woodpeckers was higher in the high-density snag areas, and black-backed woodpeckers did not nest and were not found in the low-density snag areas. There was 1 nest each in the medium- and high-density snag areas over the 2 years of study [25]. Black-backed woodpecker nest sites were located 2 to 4 years after a severe fire in western Montana. Approximately 700 acres (275 ha) of the 4,000-acre (1,600- ha) burned area were salvage-logged the winter following the fire, with most of the merchantable timber (>6 inches (15 cm) DBH) removed. There were significantly more black-backed woodpecker nests in unlogged stands compared to logged stands (P<0.01); 10 nests were found in the unlogged stands and none were found in the logged stands. Because enough snags were retained to meet suggested management recommendations for the black-backed woodpecker, the authors suggested that factors other than snag presence (e.g., food abundance) may have determined nesting location [41].
Though several studies found a relationship between black-backed woodpecker use of a burned area and salvage-logging intensity, one study found no significant differences in black-backed woodpecker abundance under various salvage-logging intensities. Approximately 1 year after a severe wildfire in ponderosa pine forests in central Oregon, 6,212 acres (2,514 ha) of the 21,031-acre (8,511-ha) burned area were salvage logged using 2 logging intensities: moderate (30 snags retained/ha) and heavy (5-6 snags retained/ha). Black-backed woodpecker abundance was significantly lower in salvage-logged stands compared to unlogged stands (P=0.005), but there was no detectable difference in abundance between logging intensities [13]. In another study, the relationship between logging intensity and black-backed woodpecker response was not clear. Black-backed woodpecker abundance was sampled 11 and 12 years after a 37,000-acre (14,900-ha) fire in western Labrador. Between sampling years, snags were removed from 25-acre (10-ha) plots. Snag removal consisted of 25%, 50%, and 100% removal at each plot, creating patch openings of 6.2 acres (2.5 ha), 12 acres (5 ha), and 25 acres (10 ha) within a stand of contiguous snags. Black-backed woodpecker abundance was significantly lower in treated stands compared to untreated stands (P=0.015). Black-backed woodpeckers were absent from the 25%- and 100%-removal plots and had a reduced presence on the 50%-removal plots [84].
The observations from one study suggest that the spatial arrangement of a prescription may influence black-backed woodpecker use of a salvage-logged area. In recently burned (postfire years 3-4), salvage-logged stands in Montana, some black-backed woodpeckers occurred in the salvage unit, but they generally were only found in unlogged patches within the logged area [32].
The impacts of salvage logging on black-backed woodpeckers likely vary by fire characteristics, logging prescription, and local conditions. The following sources contain recommendations (e.g., snag management and harvest guidelines) related to black-backed woodpeckers and postfire salvage logging: [28,35,39,45,61,63].
Because the suitability of postfire habitats is ephemeral, black-backed woodpeckers rely heavily on the consistent occurrence of fire in some parts of their distribution. One review states that fire exclusion is detrimental to black-backed woodpeckers because it prevents the occurrence of large, severe wildfires that create suitable habitat [17].
Fire size and season do not appear to influence black-backed woodpecker use of a burned area. Black-backed woodpeckers use burned areas of all sizes, including small burns <250 acres (100 ha) [3,22,29,30] (low of 15 acres (6.25 ha) [3]) and large burns exceeding 74,000 acres (30,000 ha) [2,8,108]. They also occupy areas burned in the breeding (April-July) [7,29,30,35,36,45,60,62,63,65,93,108] and nonbreeding (August-October) [2,8,22,26,30,41,46,107] seasons.
Fire severity: The available literature documents black-backed nesting in areas burned at severities characterized as low [107], moderate [96,97,107], high [8,25,29,32,41,62,63,96,97,107,108], or mixed [2,5,14,22,34,46,77,78,93,107].
Fires of relatively high severity appear to be important for black-backed woodpeckers, possibly because more severe fires result in more dead trees for foraging and breeding [45]. Data from 13,337 sample points in burned areas in northern Idaho and Montana showed the probability of black-backed woodpecker detection increased with fire severity (P<0.001) [40].
Severely burned forest may be used by breeding and foraging black-backed woodpeckers. Photo courtesy of the National Park Service.Two, 3, and 8 years after stand-replacing wildfire in coniferous forests in Alberta, the presence of black-backed woodpeckers was best explained by the proportion of severely burned trees; black-backed woodpeckers occupied sites with a mean density of 9.6 severely burned trees/100 m² [35].
Vierling and others [107] found that 2 to 4 years after a mixed-severity fire in South Dakota, black-backed woodpecker nest sites had a lower mean percentage of the landscape burned by low-severity fire compared to random locations (20.8% vs. 24.9%). Reproductive success was highest in severely burned areas [107].
Reproductive success of black-backed woodpeckers nests 2 to 4 years after fire in the Black Hills, South Dakota. Reproductive success was measured as the percent of nests that fledged at least 1 young [107]. Fire severity High Moderate Low Number of nests 10 6 5 Daily survival rate (SE) 0.995 (0.005) 0.982 (0.12) 0.986 (0.014) Percent reproductive success 80 50 60The results from another study show an inconsistent relationship between fire severity and black-backed woodpecker abundance. Over postfire years 1 to 3 in coniferous forests in Wyoming, more pairs of black-backed woodpeckers were found in areas burned by moderate-severity fire compared to areas burned by high-severity fire, though breeding pairs were found in both. However, numbers showed no consistent trend across years [97].
Pairs of breeding black-backed woodpeckers/100 acres following fire in coniferous forests of Wyoming [97] Burn severity Postfire year 1 2 3 Moderate 2 5 2 High 5 +* 2 * =Present outside of survey area.Several studies suggest that in a landscape burned by mixed-severity fire, black-backed woodpeckers prefer areas burned at high severity, though preference may depend on life history need (e.g., nesting vs. foraging). One to 5 years after a mixed-severity wildfire in California, black-backed woodpecker foraging only occurred in severely burned, unlogged forests, not in severely burned logged forests, moderately burned unlogged forests, or unburned forests [28]. One to 2 years after a mixed-severity wildfire in black spruce and jack pine forests in northeastern Alberta, black-backed woodpecker abundance increased with increasing burn severity (P<0.05), an association that was most pronounced the first summer after fire [45]. Two years after a mostly severe fire in black spruce forests in southern Quebec, black-backed woodpeckers nested in areas of severe fire but foraged on more moderately-charred trees; moderately charred trees were preferred over severely charred trees (P<0.01) [63].
Low- and mixed-severity fires may be important in supporting woodpecker populations over time. Though black-backed woodpecker use of areas burned by low-severity fire is infrequently documented in the available literature, one study suggests that areas burned at low severity may be important for the long-term persistence of black-backed woodpecker populations in a given area. Black-backed woodpeckers were detected 6 years (74% of 80 sampling locations) and 8 years (27% of 55 sampling stations) after a mixed-severity fire in mature black spruce and jack pine forests in Quebec. Their occurrence was not related to fire severity class in either sampling year. However, the authors attributed their long-term persistence to areas burned by low-severity fire within a landscape that mostly burned at high severity. Lower fire severity in some areas delayed tree mortality, which likely maintained appropriate tree hosts for several insect species that black-backed woodpeckers consume [65]. After wildfire in Alaska, male black-backed woodpeckers shifted foraging from severely burned trees in postfire year 1 to moderately burned trees in postfire year 2 [60].
Black-backed woodpeckers inhabit plant communities that experience a wide range of fire regime characteristics. The Fire Regime Table summarizes characteristics of FIRE REGIMES for vegetation communities in which black-backed woodpeckers may occur. Find further fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Black-backed woodpeckers commonly occur in burned areas in many parts of their distribution, using areas burned by both prescribed fire [22,29] and wildfire [2,5,8,14,22,25,26,28,36,41]. Fire may attract black-backed woodpeckers to areas where they were not previously documented [22,26,90] or found breeding [3,22,29]. Burned areas are considered a critical black-backed woodpecker habitat in some areas like the Interior Rocky Mountains, where significantly more (96% of detections from 13,337 sampling points) black-backed woodpecker detections were from recently burned (postfire years 1-4) forest compared to unburned vegetation types (P<0.001) [40].
Black-backed woodpecker response to fire will be discussed in relation to the following topics:
Fire generates snags suitable for black-backed woodpecker nesting. Black-backed woodpeckers commonly nest in burned areas, including areas burned by wildfire [5,19,32,63,78,93,107,108] and prescribed fire [22,29]. Black-backed woodpeckers nest in forests burned by fires of varying severity, including mixed [19,78,93,107], moderate [5], and high [5,32,108] severity. They may nest in areas salvage-logged after fire [19,25,32,78]. The following table summarizes literature that documents black-backed woodpeckers nesting in burned areas.
Summary information of black-backed woodpecker nesting in burned areas Location,California,
white fir
California,
red fir
Idaho,
mixed conifer
Montana and Idaho,
mixed conifer
Montana: 3,4 years
Idaho: 1,2 years
Nested in logged and unlogged areas, but more nests were in unlogged areas [32].
Oregon,Wyoming,
mixed conifer
Alberta,
mostly quaking aspen, some white and black spruce
Quebec,
black spruce
Nest-site selection: While many studies document black-backed woodpecker nesting in burned areas, only a few studies (e.g., [19,63,78,107]) examine nest-site selection. Variables positively related to nest-site selection include snag density [19,63,78,107], distance from edge, fire severity [107], prefire crown closure [78], and prefire stand age [63]. Selection for large snags may be positive [78] or negative [19].
Black-backed woodpecker nest searches were conducted for 4 years following a mixed-severity fire in the Black Hills of South Dakota. Twenty nests were found 2 to 4 years after fire. Compared to random locations, nesting areas were farther from unburned edges of forest (1,988.02 feet (605.95 m) vs. 553.48 feet (168.7 m)), had less of the landscape burned at low severity (20.8% vs. 24.9%), and had a higher snag density within 37.1 feet (11.3 m) of the nest sites (26.8 vs. 13.3 snags) [107]. Black-backed woodpecker nests were located following 2 mixed-severity wildfires in Idaho, during postfire years 1 to 12. Based on information from 51 nest sites, black-backed woodpeckers nested in larger snags (mean nest snag DBH approximately 16 inches (41 cm) DBH) and nested in areas with higher snag densities (mean snag density approximately 325 snags >9 inches (23 cm) DBH/ha) than what was randomly available (P<0.05). Nest sites were best predicted by nest snag DBH, snag density, and prefire crown closure (40%-70%) (all positive; P<0.05) [78]. One to 3 years after fire in black spruce forests of southern Quebec, black-backed woodpeckers concentrated nesting in areas that were mature forest prior to fire. Nest sites contained higher proportions of burned forest than random sites (P=0.07). Snag densities were higher in nest tree plots than in random plots (P<0.05), with density of snags >6 inches (15 cm) DBH 3 times higher in nest sites than random sites [63].
One study examined nest-site selection at multiple scales 1 to 4 years after wildfire in mixed-conifer forests in south-central Oregon. Some portions of the study area were salvage-logged, but prescriptions did not significantly reduce snag numbers or diameters within treatment units, and variables relating salvage logging to nest-site selection were not significant. Variables related to snag density were the strongest predictor of nest locations when vegetation was assessed within 165 feet (50 m) and 1,640 feet (500 m) of a nest. Within 165 feet (50 m) of a nest, nest site was positively related to snag density, average snag diameter, and logged stump density and negatively related to nest tree DBH and prefire crown closure. Within 1,640 feet (500 m) of a nest, the odds of nest occurrence nearly doubled for every 50 additional snags >9 inches (23 cm) DBH. Among trees large enough to support a nest cavity (≥6 inches (15 cm) DBH), black-backed woodpeckers chose smaller snags, with every 2-inch (5-cm) increase in DBH decreasing the odds of nesting by 15% [19].
Foraging in burned areas: Fire creates habitat for the bark and wood-boring beetles that are a preferred food item for black-backed woodpeckers (see Diet). Black-backed woodpeckers commonly forage in burned forests following prescribed fire [29] and wildfire [60,63,70]. Burned areas are used for foraging in the breeding [32,35,57,63,64,70] and nonbreeding [7,46,110] seasons. Selection of foraging sites may occur at the tree or the stand level.
Foraging tree selection: In burned forests, black-backed woodpeckers generally forage on relatively large, dead trees. Tree species and the amount of charring may also influence foraging tree selection. Few studies (e.g., [64]) investigated the presence of prey items in relation to foraging tree selection.
Black-backed woodpeckers often forage on dead trees in burned areas. After a stand-replacing prescribed fire in mixed-conifer forests in central Washington, black-backed woodpeckers foraged extensively on dead but foliated trees, though large areas of dead, defoliated trees were available [29]. One year after a wildfire in jack pine forests in Quebec, black-backed woodpeckers foraged on large, deteriorated snags that had high densities of insect entrance holes and larval exit holes [64]. Black-backed woodpeckers foraged primarily on dead trees in burned areas in California [28], Minnesota [3], and Washington [46].
Relatively large trees are often chosen for black-backed woodpecker foraging, though this pattern is not universal. Black-backed woodpeckers foraged on relatively large trees in California [28], Idaho, Montana [70], and Quebec [63,64], and on relatively small trees (average 7 inches (18 cm) DBH)) in South Dakota and Wyoming [57].
Black-backed woodpeckers may forage preferentially on certain tree species, though the preferred species varies by location. In the spring and summer 3 years after a stand-replacing fire in a boreal forest of east-central Alberta, both male and female black-backed woodpeckers selected jack pine more and white and black spruce less than expected by chance (P=0.015), though all 3 tree species were used [35]. Tree species preferred for foraging also differed between 2 sites burned by stand-replacing wildfire (postfire years 1 and 2) in Idaho and Montana [70]. Following stand-replacing fire at 3 mixed-conifer sites in Montana and 1 in Idaho, black-backed woodpeckers foraging in the breeding season used Douglas-fir more than expected based on its availability (P<0.001) [32]. Winter foraging patterns were observed 1 to 4 winters after a mixed-severity wildfire in mixed-conifer forests in northeastern Washington. Black-backed woodpeckers foraged exclusively on western larch and Douglas-fir, the 2 most abundant tree species. This pattern differed from the available distribution of tree species (P<0.001) [46].
The severity of tree charring sometimes influences foraging tree choice, though this selection pattern may change over time. Two years after a severe wildfire in black spruce forests in southern Quebec, breeding black-backed woodpeckers preferred moderately charred trees to severely charred trees (P<0.01). The authors noted that the moderately burned trees used for foraging often occurred at the edges between burned and unburned areas [63]. The breeding season after fire in jack pine forest in Minnesota, black-backed woodpecker pairs were observed feeding almost exclusively on severely burned jack pine, most of which appeared to be dead [3]. Male black-backed woodpeckers shifted from foraging on severely burned to moderately burned trees between the 1st and 2nd year after a human-caused fire in a white spruce forest in interior Alaska [60]. In the spring and summer 3 years after a stand-replacing fire in a boreal forest of east-central Alberta, burn severity was not significantly related to forage tree selection. Both sexes selected moderately burned, large-diameter (>6 inches (15 cm)) jack pines more and moderately burned, medium-diameter (3-5.9 inches (76-150 mm) DBH) spruce trees less than expected by chance (P<0.10) [35].
Foraging stand selection: As of this writing (2011), studies examining foraging habitat selection at the stand level within burned areas were limited. The available studies suggest that foraging habitat selection may vary with fire severity and/or salvage logging. One to 5 years after 2 fires in west-central California, black-backed woodpeckers were only found foraging in severely burned, unlogged forests and not in severely burned logged forests, moderately burned unlogged forests, or unburned forests. At least 5 to 15 large snags/ha were retained in salvage-logging treatments [28]. The results of one study suggest that factors other than prey availability may influence habitat selection in the breeding season. Breeding-season foraging selection was studied at 2 locations that varied in canopy tree species and time since stand-replacing wildfire (1 vs. 2 years after fire). Patches where foraging occurred did not have higher prey densities than random patches, and foraging did not occur in relatively prey-rich areas at one site. The author suggested that foraging habitat selection relies on a variety of factors that likely vary by site, including but not limited to tree species and insect density [70].
Unburned forest near burned forest may provide important foraging habitat. A study in ponderosa pine forests in southwestern South Dakota and northeastern Wyoming examined foraging patterns in burned and adjacent unburned forest and found that most foraging occurred in unburned areas. Black-backed woodpeckers were observed in burned areas within a year of a 321,000 acre (130,000 ha) wildfire. Over 2 years of observations, most (76%) foraging bouts occurred in unburned areas. Foraging locations had less understory structure and more canopy cover (P<0.05) than random sites. Black-backed woodpeckers foraged in areas with higher snag basal area (P=0.002), greater snag density (P=0.021), and lower snag height (P=0.013) than what was available throughout the study area [57].
Relative use of burned and unburned areas: Black-backed woodpeckers are more abundant [26,46,57,58,65,71] and more likely to nest [2,8,22,29,34,96] in burned areas compared to nearby unburned areas.
Abundance or occurrence of black-backed woodpeckers in burned areas compared to adjacent unburned areas Location Forest type Time since fire (years) Abundance or occurrence details California pine-red fir 6-8 Black-backed woodpecker territory density was 0.7 territory/plot/year in burned areas and 0.1 territory/plot/year in unburned areas approximately 1,300 feet (400 m) from the fire perimeter [71]. Minnesota jack pine and black spruce 1,3,7 Black-backed woodpeckers occurred (but were not territorial) in burned areas and were not detected in 80- and 98-year-old unburned forest [26]. South Dakota and Wyoming ponderosa pine 1 Black-backed woodpecker detection was higher in burned forest (1 woodpecker/2.5 sampling transects) than unburned forest (1 woodpecker/10 sampling transects) [57]. Washington mixed conifer 1-4 Overwintering black-backed woodpeckers were significantly more abundant in burned than unburned areas in all years (P=0.001); abundance was 0.406 individual/sampling point in burned areas and 0.019 individual/sampling point in unburned areas [46]. Newfoundland black spruce 5 Black-backed woodpeckers were detected but uncommon in burned areas in the breeding season. They were not found in unburned, clearcut sites that were 5, 14, and 27 years old [87]. Quebec jack pine and black spruce <2 Black-backed woodpeckers were detected at 80% of sampling areas that were recently burned; 39.1% of sampling areas that were in mature coniferous forest <1.2 miles (2 km) from a recently burned area; and 30.8% of sampling areas that were in mature coniferous forest >1.2 miles (2 km) from a recently burned area [42]. Saskatchewan mixedwood (quaking aspen, white spruce) and jack pine 3 Black-backed woodpeckers were only detected in burned areas, but at an abundance too low to analyze. They were not found in unburned forests of any vegetation type [58].The results of 2 studies suggest that higher abundance in burned areas may vary by season or change over time. Six years after mixed-severity wildfire in black spruce and jack pine forests in northwestern Quebec, black-backed woodpeckers were detected at 74% of 80 sampling points and were significantly more abundant in burned areas versus unburned areas (P<0.05). Eight years after fire, black-backed woodpeckers occurred at 27% of 55 sampling points, and there was no significant difference between burned and unburned forest [65]. One year after a mixed-severity surface fire in Yosemite National Park, California, black-backed woodpecker relative frequency was higher in the breeding season (late May to mid-July) in unburned forest than burned forest (P<0.05), but the reverse was true in the late breeding season (mid-July to mid-August) (P<0.05). Two years after fire, black-backed woodpeckers were detected in both burned and unburned forest, but their frequency was higher in burned forest in both the breeding and late breeding seasons (P<0.05). The author suggested that black-backed woodpeckers were initially limited by nest sites in the burned forests because the fire may have consumed existing snags and did not kill enough trees to provide new nesting snags. The author also noted that the burned and unburned study areas were located close to each other, so it was likely that individuals moved between both habitat types while foraging [22].
Several studies also document black-backed woodpeckers nesting in burned forest but not in adjacent or nearby unburned forest, including 1 and 2 years after a mixed-severity wildfire in Wyoming [96], 2 years after a mixed-severity prescribed fire in California [22], 1 to 3 years after a mixed-severity wildfire on the Upper Peninsula of Michigan [2], and 1 year after a stand-replacing prescribed fire in Washington [29]. A few studies found black-backed woodpeckers nesting in both burned and nearby unburned forest, though nest density was higher in the burned forest. Six, 7, and 8 years after a 39,000 acre (16,000 ha), high-severity wildfire in north-central California, black-backed woodpeckers bred in both burned and unburned forest, though more breeding took place in burned areas. Surveys suggested that black-backed woodpecker density over the 3-year study period was 3.2 pairs/100 acres in burned forest and 0.5 pair/100 acres in unburned forest [8]. Over 2 years of sampling in lodgepole pine forests in the Great Yellowstone Ecosystem of Idaho and Wyoming, black-backed woodpeckers did not nest in recently clearcut forest. Over both years, 1 nest was found in undisturbed, late-seral forest. In areas burned by a mixed-severity wildfire, 1 nest was found 1 year after fire, and 13 were found 2 years after fire [34].
Spatial use of a burned landscape: A burned landscape contains many features that may be more or less suitable as habitat for black-backed woodpeckers. Black-backed woodpeckers have been documented using both the interior and perimeter of burned areas, though few studies have examined their relative use or importance. For example, black-backed woodpeckers used both the interior and edge of an area severely burned by wildfire in South Dakota and Wyoming [57].
Some observations suggest that fire edges are well-used by black-backed woodpeckers. In year-round surveys 1 to 3 years after an 8,700-acre (3,500-ha) wildfire near Fairbanks, Alaska, black-backed woodpeckers were not observed in the fire interior and primarily used the edge of the burned area [60]. Two years after a mostly severe fire in black spruce forests in southern Quebec, the foraging locations of 10 black-backed woodpeckers were concentrated on moderately-charred trees, which occurred at the edges between burned and unburned areas [63].
While edge habitat may provide foraging opportunities, 2 studies suggest that black-backed woodpeckers may nest farther from fire edges to reduce predation risk. In models of nest survival of 46 nests 1 to 12 years after 2 mixed-severity wildfires in Idaho, nest survival probability increased with distance to unburned forest. The authors suggested that this pattern may be the result of reduced predation risk in burned forest, with unburned forest acting as a source for nest predators such as tree squirrels [79]. Two to 4 years after a mixed-severity wildfire in South Dakota, black-backed woodpeckers nested farther from unburned forest edges compared to random locations (1,988 feet (606 m) vs. 553 feet (169 m)), which the authors also linked to reduced predation risk [107].
One study found that patches of live forest within a burned matrix were used by black-backed woodpeckers. Five years after a mixed-severity wildfire in a boreal forest of northeastern Alberta, black-backed woodpeckers were uncommon and only found in unburned patches within a burned area. They were not detected in burned areas, continuous forest adjacent to a burned area, or forest patches that had been clearcut prior to the fire [95].
Importance of time since fire: Some reviews state that black-backed woodpeckers prefer or are most abundant in recently burned forests [17,80]. Recently burned forest provides both increased foraging opportunities as insect populations increase for a short time after fire [35,60,77] and reduced predation risk, because it may take several years for potential nest predators to recolonize a burned area. As time since fire increases, snags begin to fall naturally, leading to a decline in nesting and foraging opportunities. Habitat conditions for potential predators may also improve as time since fire increases (reviewed by [79,80]).
Few studies follow a particular black-backed woodpecker population for long periods of time or monitor burned areas beyond the first few years. Studies comparing several burned sites of different ages seldom sample the full spectrum of postfire years. Both fire characteristics (e.g., severity) and local conditions (e.g., forest type, management history) also vary by study, making widespread inferences difficult.
Studies monitoring the same burned area over time generally support the assertion that black-backed woodpeckers are most abundant in recently burned forest, though the actual years of population peaks and declines vary by site. One study sampled black-backed woodpecker populations 7 different years, ranging from 1 to 30 years after a stand-replacing fire in northeastern Minnesota. Black-backed woodpeckers occurred 1, 3, and 7 years after fire and were not detected 19, 22, 23, or 30 years after fire [26]. Black-backed woodpecker territories were studied at 3 time intervals following a stand-replacing wildfire in north-central California: postfire years 6 to 8, postfire years 15 to 19, and postfire year 25. Territories were found in burned forest 6 to 8 years postfire but were not found in the later sampling periods [71]. Black-backed woodpecker population trends were followed year-round after wildfire in Alaska. Black-backed woodpeckers were common 1 year after the fire, most abundant the fall 1.5 years after the fire, and continued to be abundant through the fall 2.5 years after the fire. By postfire year 3, they were considered rare. They were no longer detected by the 4th winter after the fire [60]. One study observed nest density 1 to 12 years after 2 mixed-severity fire wildfires in western Idaho. Black-backed woodpecker nest density peaked in postfire years 4 and 5 [77]. After a severe wildfire in mature and young forest in central Quebec, black-backed woodpecker nest density was highest the 1st year after fire and declined significantly the 2nd and 3rd years (P<0.001); the 2nd year after fire, nest density was about half of what it was the 1st year [62]. Black-backed woodpecker abundance declined between 6 and 8 years after a mixed-severity wildfire in black spruce and jack pine forests in northwestern Quebec [65].
Several studies compare black-backed woodpecker populations in different forests at different times since fire. The results of these studies suggest that in burned areas, black-backed woodpeckers are most common in recently burned forest. One study examined black-backed woodpecker presence or absence in burned areas of various ages in Alberta: 3, 4, 8, 8, 16, and 17 years after fire. Black-backed woodpeckers were detected in areas burned 3,4 and 8 years previously, and their occurrence was not significantly different between these different stand ages. They were not detected in area burned 16 or 17 years previously; their numbers were significantly lower 16 years after fire compared to 8 years after fire (P<0.1) [35,36]. A review of available literature on the presence of black-backed woodpeckers after fire in northern Rocky Mountain coniferous forests reports that black-backed woodpeckers were most likely to be detected <10 years after fire. They were detected in 78% of the studies conducted in areas burned <10 years previously (23 sites), and they were not detected in areas burned 10 to 40 years previously (5 sites) [38]. In a study examining the abundance of black-backed woodpecker pairs in areas of varying age since fire (range: 1-304 years after fire ) in coniferous forests in Yellowstone and Grand Teton National Parks, black-backed woodpecker pairs were found in areas 1 to 3 years after fire, but they were absent from areas >5 years after fire [97]. In north-central Alberta during the breeding season, black-backed woodpeckers were only found in areas burned 1 year previously, and not in areas burned 14 or 28 years previously [33]. Data from 13,337 sample points in northern Idaho and Montana showed that black-backed woodpeckers occurred most (96% of detections) in recently burned (postfire years 1-4) areas compared to unburned vegetation types (P<0.001) [40].
This section summarizes life history characteristics that may be relevant to fire ecology and is not meant to be comprehensive. For extensive information regarding the life history of the black-backed woodpecker, see Dixon and Saab [17], a synthesis that is frequently cited in this section.
Physical description: The black-backed woodpecker is a medium-sized woodpecker (9 inches (23 cm) long, 2-3 ounces (61-88 g), wing length approximately 5 inches (12 cm)). Adults have solid black upperparts. Underparts are white and heavily barred with black on the sides and flanks. Males have a prominent yellow patch on the center of the crown. Juveniles are similar in appearance to adults but have duller coloration. The black-backed woodpecker has 3 toes on each foot, 2 directed forward and 1 directed backward [17].
Male black-backed woodpecker. Photo courtesy of Richard Hutto.Life span: The life span of the black-backed woodpecker is unknown, but it may be similar to that of the American three-toed woodpecker (Picoides dorsalis) and the white-headed woodpecker (P. albolarvatus): 6 to 8 years. The age at first breeding is unknown [17].
Social bonds: Black-backed woodpeckers appear to remain paired throughout the year [17].
Population dynamics: Population trends of the black-backed woodpecker are difficult to study due to the ephemeral nature of some preferred habitat (e.g., burned or insect-killed forest), movement of populations, and population irruptions [17]. The low density of populations in forests lacking disturbance also makes it difficult to make inferences about population trends in these habitats.
Some research has identified habitats that may act as either sources or sinks for black-backed woodpecker populations. The 1st year after a high-severity fire in mature (>23 feet (7 m) canopy height) and young (<23 feet) black spruce forests in central Quebec, annual black-backed woodpecker productivity was sufficient to compensate for mortality. The 2nd year after fire, this relationship held in mature but not young forests [62].
Home range: Black-backed woodpeckers maintain large home ranges. Home range size is variable and may reflect the season or habitat type in which home range estimates were calculated.
Descriptions and sizes of black-backed woodpecker home ranges using minimum convex polygon calculations Location Idaho Oregon Quebec Habitat Description burned coniferous forestsWithin individual studies, home range size was often related to habitat characteristics. In industrial coniferous forests in southeastern Quebec, home range size increased as the distance between >90-year-old conifer patches within the landscape increased [101]. In lodgepole pine forests infested with mountain pine beetles in western Oregon, home range size was inversely related to the proportion of unlogged and mature or "overmature" stands within the home range; the largest home range had the smallest proportion of unlogged and mature or overmature habitat [21]. In burned coniferous forests in southwestern Idaho, home range size was significantly smaller 6 years than 8 years after fire (P<0.05). The authors suggested that as preferred food items decreased with time since fire, black-backed woodpeckers needed a larger foraging area [18].
Black-backed woodpeckers may have areas of concentrated use within a home range. In burned coniferous forests in southwestern Idaho, 4 male black-backed woodpeckers concentrated activity within 2 to 8 areas of a home range [18]. Intraspecific home range overlap appears to be limited. In logged and unlogged lodgepole pine forests infested with mountain pine beetles in western Oregon, intraspecific home range overlap was limited or nonexistent except for paired individuals near a nest site. Interspecific home range overlap was common [21].
Migration: Black-backed woodpeckers do not exhibit a regular latitudinal migration, but populations are subject to periodic irruptions outside of their resident range. Irruptive movements occur largely in response to the availability of food resources, as food either becomes widely available or unavailable in an area [17]. Most irruptive behavior takes place in the winter [113]. Irruptive movements to areas with abundant food (e.g., after an insect outbreak) may translate into highly successful breeding in those areas [17].
Dispersal: The dispersal of juvenile black-backed woodpeckers from natal sites has not been well studied as of this writing (2011) [17]. One bird-banding project along the St Lawrence River in eastern Quebec documented the migration or dispersal of primarily juvenile (i.e., hatch-year) black-backed woodpeckers from mid-September to mid-November (5 years, n=343) (Observatoire d'oiseaux de Tadoussac unpublished data cited in [37]).
One study used patterns of genetic variation to investigate dispersal dynamics of the black-backed woodpecker in western North America. The results suggested that extensive gene flow occurred in continuous boreal forests. However, male movements were responsible for most of the gene flow between populations in continuous boreal forest and smaller, isolated populations in South Dakota and Oregon. Large unforested areas apparently impede movement of female black-backed woodpeckers [69].
A study in eastern Quebec looked at population age structure in burned (postfire years 1-4) and unburned black spruce and jack pine forests. Though all age classes and both sexes were found in both burned and unburned forests, more young birds (3 years after hatching) were found in burned forest and more old birds (>3 years after hatching) in unburned forest (P=0.0088). These results suggested that primarily 2nd-year birds colonized burned areas [37].
Breeding: Black-backed woodpeckers are primary cavity nesters and use both live [21,41,44,51,56,92] and dead [14,21,25,41,51,57,92] trees for nesting. Nest construction is done mostly by male black-backed woodpeckers [17]. The black-backed woodpecker typically makes a new nest cavity each year [17], though the use of the same cavity from year to year has been documented in south-central Oregon [19] and east-central Alberta [35]. The height of black-backed woodpecker cavities varies, ranging from an average of 3.95 feet (1.20 m) from 2 nests in Idaho [56] to 23 feet (7 m) from 11 nests in Montana [14]. See Breeding habitat for information on the habitat used for black-backed woodpecker breeding.
Phenology: Black-backed woodpecker breeding begins in the spring and extends into midsummer.
Summary of black-backed woodpecker breeding phenology [17] Activity Date range Nest building April to June Egg laying late April to early June Incubation late May to late June Fledging early June to early JulyClutch size and fledging rate: Clutch size is usually 3 or 4 but may range from 2 to 6 [17]. Clutch size may vary by habitat. In the 1st three years after a wildfire in central Quebec, the mean number of young/nest was 3. However, nesting pairs in burned mature forest had larger clutches than those in burned young forest (n= 85 nests). [62]. Black-backed woodpeckers may renest if the initial nest fails [10,17].
Nest density: Black-backed woodpecker nest density is variable. Most studies either do not report the density of nests across a landscape or use inconsistent units for calculations, making broad comparisons difficult. Within an area, nest density may vary with stand structure [62,107]), stand age [19,62,77], or disturbance (e.g., fire [107], insect infestations (Rumble unpublished data cited in [10], or salvage logging [19,77]).
In mature boreal forests in Vermont, the nests of 3 pairs of black-backed woodpeckers were spaced about 1 mile (1.6 km) apart [51]. In mountain pine beetle-killed forests of southwestern South Dakota, nest density in 1 year was 0.13 nest/40 ha. In some areas following an insect outbreak, nesting density was as high as 3.6 nesting pairs/40 ha (Rumble unpublished data cited in [10]).
The density of breeding black-backed woodpeckers is generally higher in burned than unburned forests [17]. For 3 years following severe wildfire in central Quebec, nest density was as high as 0.11 nests/ha, among the highest nest density recorded for the species (n=111 nests). Nest density decreased over time in both burned mature and young forests (P<0.001); by the 2nd year, nest density was about half of what it was the 1st year after fire. Nest density in the burned mature forest was almost double that in the burned young forest, and this relationship was maintained through time [62]. Following wildfire in South Dakota, black-backed woodpecker nest density varied by prefire canopy cover, with sites with the highest canopy cover prior to fire having the highest nest density.
Black-backed woodpeckers nests in the Black Hills, South Dakota, 2 to 4 years after fire [107] Prefire canopy cover High Moderate Low Overall density Number of nests 11 8 1 20 Mean density/100 ha (SE) 0.28 (0.08) 0.31 (0.08) 0.03 (0.02) 0.24 (0.05)The results of nest surveys over an 11-year period after 2 wildfires in Idaho showed that nest density was relatively low in salvage-logged areas and that nest density changed over time. Nest density was significantly higher in unlogged burned forest (43 nests; mean 0.22 nest/40 ha) than burned and salvage-logged forest (8 nests; mean 0.04 nest/40 ha) (P=0.003). Nest density peaked in postfire years 4 and 5; this pattern was more pronounced in the unlogged burned forest where there were more nests. The authors suggested that the temporal changes in nest density were related to the peak and decline of beetle (Coleoptera) populations [77]. After wildfire in Oregon, nest density in unlogged and salvage-logged stands peaked in the 3rd postfire year (3.25 and 2 nests/40 ha, respectively) and then declined in the 4th postfire year. It was generally higher in unlogged than logged areas, though this pattern existed in the unlogged and logged study areas both before and after the logging treatment [19].
Nest success: Nest success varies with factors including predation [4,10,62], time of nest initiation [4,19], and habitat features such as burn severity [107].
Predation is a major cause of nest failure in both burned [10,62] and insect-killed [4] forests. After wildfire in central Quebec, success of 106 black-backed woodpecker nests declined from 84% the 1st year after fire to 73% and 25% the 2nd and 3rd years after fire. Nineteen nest failures occurred over the 3-year study, of which 47% were attributed to predation and 53% to nest abandonment. Predation rate doubled from 1st to the 2nd year after fire [62]. In mountain pine beetle-killed ponderosa pine forests of southwestern South Dakota, nest success varied by year and within a breeding season. Nest success in the 1st year was 78% and in the 2nd year was 44%. Predation was the leading cause of nest loss (89%), with 10 predation events occurring during incubation, and 7 during the nestling stage. Two nests were abandoned, both during the incubation period. Estimated nest success was high (above 80%) for nests started early in the season (late April and early May) and decreased with later nest initiation. There was no significant difference in beetle densities among nest sites [10].
One postfire study found that nest success increased with distance from unburned forests, and linked this pattern to the potential of unburned forests to act as a source habitat for predators, particularly tree squirrels (Tamiasciurus spp.). One to 12 years after mixed-severity wildfires in 2 ponderosa pine forests in Idaho, models of nest survival indicated that the following had no significant effect on daily survival: abiotic factors (temperature, precipitation), temporal factors (time since fire, calendar year, early (1-4) or late (5-12) postfire period), and biotic factors (nest height). However, nest survival probability increased with distance to unburned forest. The authors suggested that unburned forest could act as a source area for nest predators [79].
Nest success may vary seasonally in both burned [19] and insect-killed [10] habitat. Over 4 years after wildfire in south-central Oregon, success of 205 black-backed woodpecker nests was 88%. Nest survival was more related to temporal predictors (e.g., earlier nest initiation) than salvage logging or other habitat variables [19].
In burned areas, nest success may also vary with fire severity [107]. Following a mixed-severity wildfire in ponderosa pine forests in South Dakota, nest success was highest in severely burned areas (n=21 nests) [107]. For more information on this study, see Vierling and others' study in the Fire severity section of this review.
Salvage logging after fire appears to have no effect on nest success [19,76,77]. Over 4 years after wildfire in south-central Oregon, success of 205 black-backed woodpecker nests was 88%. Nest survival did not differ in burned areas with and without salvage logging [19]. Following mixed-severity wildfire in Idaho, black-backed woodpecker nest success was 100% for 17 nests in unlogged (n=13) and salvage-logged (n=4) areas burned within the previous 4 years [76].
Predators: Observations of direct predation on black-backed woodpeckers are limited. Predators of adult black-backed woodpecker include hawks such as the Cooper's hawk (Accipiter cooperii). Mammals such as red squirrels (T. hudsonicus) and northern flying squirrels (Glaucomys sabrinus) may prey on nests [17]. See Nest success for more information about the impact of predation on black-backed woodpecker nests. Reduced predation risk is one reason suggested for the use of recently burned forest by black-backed woodpeckers (reviewed by [79,80]).
Federal legal status: Black-backed woodpecker populations in the Cascade Range of Oregon, in California, and in the Black Hills are Under Review for listing as Threatened or Endangered [103].
Other status: Information on state- and province-level protection status of black-backed woodpeckers in the United States and Canada is available at NatureServe, although recent changes in status may not be included.
Black-backed woodpeckers often thrive in habitats created by large-scale disturbance, including fire and insect outbreaks. Because these habitats are ephemeral in nature and black-backed woodpecker populations are often nomadic and irruptive, managers may want to consider the potential for black-backed woodpeckers to disperse as habitat suitability decreases over time. An analysis of genetic diversity patterns suggests extensive gene flow mediated by both males and females within continuous boreal forests. Male-mediated gene flow was the main form of connectivity between populations in the continuously distributed boreal forest and smaller, isolated populations in forests of South Dakota and Oregon. Unforested areas apparently serve as a barrier to movement of female woodpeckers. Managers may want consider genetic isolation of some populations (e.g., South Dakota and Oregon) and how disturbance (e.g., increase or decrease in fires, logging, etc.) may influence dispersal, and consequently the genetic population structure, of black-backed woodpeckers [69].
Depending on management goals for an area (e.g., timber production, human safety, recreation), the disturbances that create good black-backed woodpecker habitat may be at odds with other management priorities. Management actions such as commercial logging [6,16,43,82], fire suppression [17], and salvage logging after an insect outbreak [9,21] or fire [17,18] may reduce habitat creation or quality for the black-backed woodpecker. For information on the impact of fire exclusion and postfire salvage logging on black-backed woodpeckers, see Fire Management Considerations.
Logging: Commercial logging has the potential to remove structures (e.g., large trees and snags) that are important components of black-backed woodpecker habitat. However, because black-backed woodpeckers are not particularly common in forests lacking fire or insect outbreaks, there is little documentation of the impact of logging on black-backed woodpeckers in these forest types. Most studies document only nonuse or limited use of logged areas.
A few studies have shown that black-backed woodpeckers may avoid logged areas. In black spruce forests in southeastern Quebec, black-backed woodpeckers were uncommon and restricted to mature (>200 years old) forest or recently burned areas. They were not detected in logged areas or in areas of intermediate time after fire (regeneration 7-36 feet (2-11 m) in height; also 120-year-old burned stands) [43]. Over 2 years of sampling in lodgepole pine forests in the Great Yellowstone Ecosystem of Idaho and Wyoming, black-backed woodpeckers did not nest in recently clearcut forests, though nests were found in nearby undisturbed, late-seral forest and in areas burned 1 and 2 years previously by a mixed-severity wildfire [34]. Black-backed woodpeckers were detected at a low density (13 individuals/100 ha) in mature lodgepole pine forest in southeastern Wyoming. They were not detected in nearby, regenerating lodgepole pine forests that were either clearcut 13 years previously or clearcut 13 years previously and burned by wildfire 10 years previously [16]. Data from 13,337 independent sample points in northern Idaho and Montana showed that the probability of detecting a black-backed woodpecker decreased with intensity of recent prefire timber harvesting (P<0.001). Harvest intensity was described as: "none" (no evidence based on the presence of recent tree stumps), "light harvest" (evidence of levels of tree removal associated with minor selective harvesting through moderate shelter wood cutting), or "heavy harvest" (evidence of extensive tree removal associated with a seed-tree cut or clearcut) [40].
Other studies have documented black-backed woodpeckers in logged forests, but in low numbers. In mixed-conifer forests in central Washington, black-backed woodpeckers were found mostly in unmanaged forest (0.43 individual/15 ha), but they also occurred at low density in dense shelterwood (0.06 individual/15 ha) and seed tree (0.08 individual/15 ha) stands [6]. In a literature review contrasting bird presence in burned and harvested areas over many years of postdisturbance regeneration in boreal forests of western North America, the black-backed woodpecker was only common (detected in >50% of studies) in forests 0 to 10 years after fire and in old (>76 years after fire) white spruce forests. It was rare in forests 0 to 10 years after harvest and absent from all other forests examined, including forests harvested 11 to 30 years prior [82]. Black-backed woodpeckers were rare (detected 1 to 5 times) in the breeding season in <10-year-old clearcuts (110-140 acre (46-55 ha)) in east-central Maine [72]. In west-central Maine, black-backed woodpeckers were detected at low density in industrial, mixed-conifer forest stands clearcut in the last 5 years, 20- to 60-year-old conifer stands, and mature (>60-year-old) conifer stands. [24].
Logging prescriptions that retain features like large snags and patches of residual forest may support black-backed woodpecker populations. In industrial coniferous forests in southeastern Quebec, forests were selection-logged in a way to retain large snags and residual old (>90 years old) conifer stands across the landscape. The breeding-season home ranges of 7 black-backed woodpeckers were established in areas where open and forested habitats were available. At the landscape scale, home ranges were established in areas with a high proportion of recently (<5 years) logged stands. Black-backed woodpeckers were observed nesting in the recently logged areas and traveling to old conifer stands to forage. At the home range scale, foraging occurred in old conifer stands, and recently logged areas were avoided; individuals foraged mostly in old conifer stands and never in stands logged >5 years ago. Within a home range, they avoided foraging in recently logged stands [101].
The results of one study from Alberta and Saskatchewan suggest that logging unburned boreal forest is not a useful surrogate for fire in creating suitable habitat for black-backed woodpeckers. One to 5 years after disturbance, black-backed woodpeckers were significantly more abundant in areas burned by wildfire than single- or multipass harvested stands with residual trees (P<0.05) [105].
See these references for information on managing insect-killed [4,9,21] and industrial [102] forests for black-backed woodpeckers.
Management for late-seral forests: In the absence of fire or insect-caused tree mortality, black-backed woodpeckers may depend on mature or old-growth forests to provide dead and dying trees for nesting and foraging [20,101,102]. In Newfoundland, black-backed woodpeckers were most abundant in older (>80 years) forests [85,99].
Climate change: As of this writing (2011), the potential impacts of climate change on black-backed woodpeckers had not been studied. One review suggests that if climate change increases the frequency and extent of stand-replacing fire, black-backed woodpecker populations may increase [55].Black-backed woodpeckers are often resident species and may use the same area in the breeding and non-breeding season [17]. Preferred habitat is discussed in relation to specific life history activities, including breeding, foraging, and roosting.
Breeding habitat: Black-backed woodpeckers breed in boreal and montane coniferous forests throughout their range, with forest tree composition varying geographically [17].
Female black-backed woodpecker at a nest in quaking aspen in California. Photo courtesy of Martin Meyers.Nest tree characteristics: Black-backed woodpeckers are primary cavity nesters and use both live [21,41,44,51,56,92] and dead [14,21,25,41,51,57,92] trees for nesting. Tree species, size, and the relative use of live or dead trees vary throughout the range of the black-backed woodpecker.
Tree species used for nesting by black-backed woodpeckers Nest-tree species Location Balsam fir Vermont [51] Balsam poplar Alberta [35] Black spruce Vermont [51], Alberta [35], Quebec (Nappi and others unpublished data cited in [104]) Douglas-fir Montana [14], British Columbia [92] Jack pine Alberta Quaking aspen Alberta [35] Ponderosa pine South Dakota, Wyoming [57] Tamarack Vermont [51] Western larch Montana [14], British Columbia [92] White spruce Alberta [35]Nest tree size varies throughout the range of the black-backed woodpecker. Tree height ranges from an average of 32.2 feet (9.8 m) at 4 nests in Newfoundland [86] to 77.5 feet (22.7 m) at 11 nests in Montana [14]. Diameter at breast height ranges from 9 to 20 inches (23-51cm). In some places, black-backed woodpeckers select trees that are smaller [67], larger [107] or are not significantly different [12] from what is available. Studies from Idaho [76], Montana [14,41], Oregon [21,67], and South Dakota and Wyoming [57] suggest that black-backed woodpeckers nest in trees with intact tops more often than in trees with broken tops. Black-backed woodpeckers often nest in decayed trees. All 35 nest trees examined in mountain pine beetle-killed forests in Oregon appeared to have heart decay. Thirty-five percent of the nest trees were infested with mountain pine beetles [21]. In Idaho, black-backed woodpeckers tended to nest in trees with light to medium decay, excavating cavities in the least decayed snags available [76].
See the following sources for more information about black-backed woodpecker nest tree characteristics throughout its range: Idaho [32,34,56,76,78], Montana [14,32,41,54], New Hampshire [44], Oregon [12,21,67], South Dakota [9,57,107], Washington [25], Wyoming [34,57], Alberta [35], British Columbia [53,92], Newfoundland [86,89], and Quebec [63,104]. See the following sources for information on nest-tree characteristics in habitats with different types or levels of disturbance: burned [14,25,32,34,35,41,57,63,76,78,107], insect-killed [9,12,21,67,86], logged [44,89], and no indication of recent disturbance [34,53,56,92].
Nest-site selection: Though black-backed woodpeckers may nest in forests lacking fire or insect outbreaks (e.g., [6,47,50,56,60,81,91,101]), as of this writing (2011), only studies focusing on burned or insect-killed forests generated large enough sample sizes for analyses of nest-site selections.
Black-backed woodpeckers commonly nest in burned areas (e.g., [5,19,22,25,29,32,63,71,78,93]), including areas burned by both wildfire [5,19,32,63,78,93,107,108] or prescribed fire [22,29]. Black-backed woodpeckers nest in forests burned by fires of varying severity, including mixed [19,78,93,107], moderate [5], and high [5,32,108] severity. Black-backed woodpeckers may nest in areas salvage-logged after fire [19,25,32,78]. See Nesting in burned areas for more information on nest-site selection of black-backed woodpeckers.
Black-backed woodpeckers also breed in forests with high canopy-tree mortality from insect infestations. In insect-killed forests, stand structure [4,12,21,51,67], species composition [67], snag availability [4,9,67], log availability [4], food abundance [9], and logging [21] may affect use. See the following sources for information on black-backed woodpecker nest-site selection in insect-killed forests in Oregon [4,12,21,67], South Dakota [9], and Vermont [51].
Black-backed woodpeckers may nest in areas lacking fire or insect outbreaks, though nesting usually occurs at such low frequency that it is mentioned incidentally and/or an examination of nest-site selection is impossible.
Summary of available information (2011) on black-backed woodpecker nesting in forests lacking disturbance by fire or insect outbreaks Location Plant community Breeding description Alaska white spruce forest several sightings confirmed black-backed woodpecker breeding (Wright personal communication cited in [60]) California lodgepole pine meadow and red fir forest two nests found in each forest type [71] California ponderosa pine and Jeffrey pine forest nested [50] Idaho unlogged Douglas-fir and ponderosa pine forest two nests were located 2.0 and 5.9 feet (0.6 and 1.8 m) high in live conifers [56] Minnesota mature black spruce-jack pine forest following a microburst event breeding territories occurred in low numbers (0.5 territory/6.25 ha) 2 years after a microburst and 1 year after a salvage-logging treatment [47] New Hampshire subalpine forest with balsam fir and red spruce nested in areas where snag densities were high [81] South Dakota and northeastern Wyoming ponderosa pine forest with a shelterwood silvicultural system found one black-backed woodpecker nest in surveys of 144 plots [91] Washington unmanaged forest with a heterogeneous overstory of large Douglas-fir and western larch nested in area [6] Quebec industrial conifer forest nested in recently logged areas [101]Foraging habitat: Black-backed woodpeckers forage in boreal and montane coniferous forests, often using areas opportunistically in response to insect prey availability. Most foraging occurs on the trunks of coniferous trees and logs [17].
Burned areas: Black-backed woodpeckers commonly forage in burned forests following prescribed fire [29] and wildfire [60,63,70]. Burned areas are used for foraging in both the breeding [32,35,57,63,64,70] and nonbreeding [7,46,110] seasons. See Foraging in burned areas for more information on Foraging behavior and habitat selection in burned areas.
Insect-killed areas: In beetle-killed forests, forage tree selection may depend on tree species [12], status [21], and the availability of food items [21]. Foraging stand selection may depend on components of stand structure, logging [21], and topography [12].
Ten years after a mountain pine beetle outbreak, patterns of year-round black-backed woodpecker foraging were studied in northeastern Oregon. Black-backed woodpeckers foraged in all available coniferous forest types. Almost all (97%) of the foraging bouts were on ridges. Live and dead trees were used in equal proportions. Tree species was the best indicator of live tree use; live lodgepole pine was preferred for foraging and was used 54% of the time. When foraging on snags, black-backed woodpeckers foraged mostly on trees that had been dead <2 years. Snags used for foraging averaged 13 inches (34 cm) DBH, 62 feet (19 m) in height, and had 41% of their needles [12]. One study examined Foraging behavior from April to August in logged and unlogged lodgepole pine forests with a mountain pine beetle outbreak in western Oregon. In over 395 foraging bouts, 3 black-backed woodpeckers foraged mostly (88%) in uncut stands; stands cut minimally for fuelwood were used in 12% of the bouts, and foraging was not observed in logged stands. Based on availability, black-backed woodpeckers selected for single-storied and "overmature" sawtimber stands and against plantations, clearcuts, and single-storied seedling, sapling, or pole stands. Canopy closure was <60% in 74% of the foraging stands. Black-backed woodpeckers foraged mostly (93%) on lodgepole pine, which dominated the forests. Dead trees were used 68% of the time, though dead trees made up only 28% of the available trees. Most (94%) of the foraging trees were recently dead snags. Mountain pine beetles had infested 81% of the trees used for foraging, but they were present in only 36% of the available trees. Mean DBH of foraging trees was 15 inches (SD=4.9, range 2-39). Mean foraging height was 17 feet (SD=11.2, range 0-60)[21].
Other areas: Information on black-backed woodpecker foraging in areas lacking fire or insect outbreaks is largely anecdotal, though one thorough study has been done.
In industrial coniferous forests in southeastern Quebec, observations of 27 black-backed woodpeckers over 2 summers and 279 foraging bouts suggested that substrate diameter and decay class were important predictors of suitable foraging substrates. Most summer foraging occurred on dying trees, snags, and downed woody debris. Most foraging events were on recently dead snags (67.2%) with a mean DBH of 7.2 inches (18.3 cm). When foraging on dead substrates, black-backed woodpeckers selected larger-diameter substrates than what was generally available (P<0.001) but showed no preference for tree species. Downed woody debris used for foraging was mainly recently dead trees in "overmature" stands that had fallen due to windthrow, but black-backed woodpeckers also occasionally used large, logged residue in cutblocks [102]. In the same area, black-backed woodpeckers foraged mostly in mature (>90-year-old) conifer stands and never in defoliated or old cut (>5 years) stands. Within a home range, they avoided foraging in recently cut (<5 years) stands [101].
In the boreal forest of southeastern Manitoba, black-backed woodpeckers foraged during the spring and summer almost exclusively on dead conifers. They foraged most often on trees 6 to 10 inches (15-25 cm) DBH [109]. In northeastern California, black-backed woodpeckers were observed foraging for beetle larvae on large-diameter trees in an old-growth, mixed-conifer forest in the breeding season [20]. In northern California, 2 pairs of black-backed woodpeckers foraged in wind-damaged Douglas-fir and white fir forests, 1.5 years after the wind event. They were seen more frequently foraging on standing, broken-off trees than on down trees [111].
Roosting habitat: Roosting habitat of black-backed woodpeckers had not been well studied as of this writing (2011). In logged and unlogged mountain pine beetle-killed lodgepole pine forests in western Oregon, 20 roost sites were used for a total of 24 nights by 4 tagged individuals from 16 June to 20 July. No roosts were in tree cavities; 4 were in concave western gall rust cankers, 2 were in deep trunk scars, 2 were on a tree trunk, 1 was in a branch fork, 1 was a dwarf mistletoe (Arceuthobium sp.) clump, and 10 locations were not determined. Mean DBH of roost trees was 11 inches (28 cm) (range 4-20 inches (10-51 cm)). Mean roost tree-height was 65 feet (20 m) (range 40-125 feet (12-38 m)). Mean roost height from the ground was 21 feet (6 m) (range 11-33 feet (3-10 m)). Lodgepole pine was used for 14 roosts. Live trees were used for most (87%) roosts. Stands characterized as mature and "overmature" sawtimber were used for roosting more than expected, while single-storied stands of seedlings, saplings and poles, and multistoried and cut areas were avoided for roosting. Mean canopy closure at roosting sites was 40%. Mean DBH of trees in roosting stands was 6 inches (15 cm). Mountain pine beetles were present in 7 and absent from 11 forest stands used for roosting. Black-backed woodpeckers did not roost in salvage-logged sites [21].
The black-backed woodpecker (Picoides arcticus), also known as the Arctic three-toed woodpecker, is a medium-sized woodpecker (23 cm (9.1 in) long) inhabiting the forests of North America.
The black-backed woodpecker was described and illustrated by the English naturalist William John Swainson in 1832 from a specimen collected near the source of the Athabasca River on the eastern slopes of the Rocky Mountains in Alberta, Canada. He coined the binomial name Picus arcticus.[2] The specific epithet arcticus is the Latin word for "northern" or "arctic".[3] The black-backed woodpecker is now placed in the genus Picoides was erected by the French naturalist Bernard Germain de Lacépède in 1799.[4][5] The species is monotypic: no subspecies are recognised.[5]
The plumage of adults is black on the head, back, wings and rump. They are white from the throat to the belly; the flanks are white with black bars. Their tail is black with white outer feathers. There is an element of sexual dimorphism in the plumage, with the adult male possessing a yellow cap. Unlike all other woodpeckers except the related American and Eurasian three-toed woodpeckers, this species has three-toed feet.
Measurements:[6]
Their breeding range is boreal forest across Canada, Alaska, the Northwestern United States, as well as northern Wisconsin,[7] the Adirondacks in New York, New England, Minnesota,[8] and Upper Michigan.[9] In particular the species is a burnt-forest specialist, feeding on the outbreaks of wood-boring beetles that feed on recently burnt trees.[10] The most important wood boring beetles taken are in the families Cerambycidae and Buprestidae, along with engraver beetles and the mountain pine beetle. Most food is obtained by pecking, a smaller proportion is obtained by gleaning off branches. Black-backed woodpeckers are generally non-migratory but historically have undertaken intermittent irruptions.
Nest excavation occurs in April and May; a fresh nest is drilled each year into the sapwood of dead trees. Abandoned nests are used by other species of bird to nest in. The female lays three or four eggs, and incubation duties are shared between both parents, although the male alone incubates during the night. Upon hatching the altricial chicks are brooded until the nestling phase. Both parents feed the chicks, which take about 24 days to fledge.
The call note of the black-backed woodpecker is a single, sharp pik, and is lower pitched than the call of the American three-toed woodpecker.
The black-backed woodpecker (Picoides arcticus), also known as the Arctic three-toed woodpecker, is a medium-sized woodpecker (23 cm (9.1 in) long) inhabiting the forests of North America.
