Crested auklets use visual, chemical, tactile, and acoustic modes of communication. They are very vocal during the breeding season and in flocks at sea. Nearly all of their communication occurs during the daytime when these birds are most active. Six different forms of vocal communication among adult crested auklets have been observed. They include barking, trumpeting, cackling, hooting and whining. A bark is a form of vocalization used by both sexes. It sounds like the “yap” of a small dog (Jones 1993). These “barks” are often associated with locomotion, such as when crested auklets leave the colony. This is a type of signal that can function as a location signal or a contact call to other birds in the flock or colony. Crackling is a vocalization that is performed by auklet pairs in the process of courtship. Crackling sounds like a series of clucking noises. This form of vocalization serves an important function in pair bonding. Hooting occurs from within crevices and sounds like a series of rhythmic soft bark-like sounds (Jones 1993). Whining is a form of softer communication in that is performed by solitary auklets that are not yet mating. Males emit a type of vocalization referred to as trumpeting. It is a form of sexual advertisement used in courtship displays. It consists of a series of honk-like sounds that increase in rhythm. These honking sounds are performed along with specific courting displays by that particular male. Trumpeting vocalizations are performed on top of large rocks at nesting sites or from staging areas at sea. Breeding males are frequently seen trumpeting in the pre-laying stage and then again during the chick-rearing stage (Jones 1993). Auklet chicks are also vocal. They are vocal throughout the day, especially while their parents are at and away from the nest site. Vocalizations consist of soft peeps and loud warble-whistles.
Few studies have been conducted on the exact purpose of plumage odor in crested auklets. During the breeding season these birds produce a pungent citrus-like odor, similar to tangerines. Plumage odor may have a social function in courtship because courtship involves a great deal of touching with the birds' bills in the strongly scented areas on their partners' necks (Jones 2004). The odor seems to play a more important role when these birds are in close contact with one another in colonies and at sea. Their behavior in these places indicates that the odor plays an important role in socializing and courtship because they closely interact and sniff each other. Behaviors such as rump-sniffing and neck-twisting are displayed during the more advanced stages of courtship among this species.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: duets ; pheromones
Perception Channels: visual ; tactile ; acoustic ; chemical
The status of the crested auklets on the IUCN Red List of threatened species is least concern. They are not on the United States Endangered Species Act list, but they are protected by the Migratory Bird Treaty Act.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no direct negative effects of crested auklets on humans.
Crested auklets sometimes provide food for Eskimo and Aleut people. They are also valuable in research and education.
Positive Impacts: food ; research and education
The primary way in which this bird species affects its ecosytem is its role as prey for other animals.
Mutualist Species:
Crested auklets eat crustaceans and other marine invertebrates including Thysanoessa euphausiids, mysids, hyperiids, gammarids, calanoid copepods, fish, and squid. They are deep ocean divers and forage underwater in social groups on colonial euphausiids on the ocean floor. Underwater, they pursue their prey in a rapid wing-propelled underwater flight (Jones 1993).
Animal Foods: fish; mollusks; aquatic crustaceans; other marine invertebrates; zooplankton
Plant Foods: phytoplankton
Primary Diet: carnivore (Piscivore , Eats non-insect arthropods, Eats other marine invertebrates); planktivore
Crested auklets are native to the Nearctic and Palearctic. They are common on remote islands and coastal areas in the Bering Sea and North Pacific (Jones 1993). They inhabit coastlines outside the Americas on the Chukotski peninsula in Eastern Siberia, Kurile Island, and other islands in the Okhotsk Sea. This species can sometimes be found wintering as far south Northern Japan (Jones 1993).
Biogeographic Regions: nearctic (Native ); palearctic (Native )
The preferred habitat of crested auklets is offshore and along the coasts of remote islands in the Bering Sea. They are one of the most abundant planktivorous sea birds found in the North Pacific and they nest in breeding colonies along with other species of auklets (Piatt et al. 1990). Rock crevices along talus slopes, boulder fields, or lava flows are critical for nesting. They situate their breeding colonies along these rocky cliffs so that they are facing the sea. Crested auklets are deep ocean foragers and often find their food far away from their nesting sites. During the winter season they flock in the nearby ice-free waters of the Gulf of Alaska and northern Japan (Hoyo et al. 1996). Little information exists on spring/fall migration among this species and their winter range.
Habitat Regions: polar ; terrestrial ; saltwater or marine
Terrestrial Biomes: tundra
Aquatic Biomes: pelagic ; coastal
Little is known about the lifespan of crested auklets in the wild or in captivity. The estimated lifespan of this species is about 7.7 years. The estimated annual survival of adults in the populations is 86% per data from studies at Buldir, Alaska. These researchers color-marked certain birds at Buldir, and then documented their lifespan.
Range lifespan
Status: wild: 8 (high) years.
Average lifespan
Status: wild: 7.7 years.
Typical lifespan
Status: wild: 8 (high) years.
Average lifespan
Status: wild: 7.7 years.
Crested auklets are relatively small birds. Males and the females are similar in appearance. They differ in appearance from other auklet species that they nest with because all of their body plumage is dark. Their upper bodies are dark-grey while their lower bodies are usually brownish-grey. They have decorative, forward-coiled facial feathers and crests that distinguish them from other common birds in their range. Both sexes have ornamental feathers and facial crests, and these features vary in size with age and mass. Male birds typically have longer decorative crests than females. Adults molt their feathers once a year in order to grow new ones. Their facial decorations will be shed throughout March and April. These facial decorations endure a great amount of wear and tear throughout the breeding season so by fall they appear rather worn. The only difference between sexes is that longer feathers are found on the napes and necks of the males. Crested auklets have a very distinct citrus-like odor in their plumage which is important for them in both social and sexual behaviors (Jones et al. 2004).
Crested auklets have prominent white irises and a white stripe of feathers on each side of their head running from behind their eyes back to their ear-coverts. Their legs are grey and they have webbed feet with coal-black claws. Their bills are bright reddish-orange with a yellow tip. During the breeding season, the bill shape of this species differs between the sexes in that the female’s bill is less curved than the male’s bill, and it is slightly smaller in size. The noticeable curvature in the male’s bill during breeding seasons is thought to help them in their agonistic encounters. On the bills are brightly colored “horny” plates called the nasal plate, subnasal plate, rectal plate, and the maxillar plate. They will lose these plates at the end of the breeding seasons and after incubation periods. During winter, their bills become dull in color and slightly smaller in appearance due to loss of their facial ornamentation and facial plates. This makes identifying sexes more difficult at this time of year.
Crested auklets are covered in down at hatching. Some hatchlings have light grey abdomens and others have black abdomens, but nearly all of them have pale-grey patches on their bottom sides. Shortly after birth, at about 5 days, they begin a pre-juvenile molt. This molt lasts until they are around a month old. Juveniles are similar in appearance to adults except that their crests may not yet be visible. Their bodies are dark grey to black and the white stripe behind their eyes begins to develop and becomes slightly visible. Their irises at this stage of development are dark grey, their bills are black, and they are without their horny plates.
Range mass: 211 to 322 g.
Average mass: 260 g.
Range length: 18 to 20 cm.
Range wingspan: 40 to 50 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike; male larger; ornamentation
Crested auklets are preyed on by avian and mammalian predators and large, predatory fish. Avian predators attack crested auklets on land or at sea usually while they are flying. On land they wait near the nesting crevices and attack as they enter and leave. Mammalian predators enter nest crevices to take chicks and the eggs. Crested auklets are vigilant at nesting colonies and at sea in order to avoid predation. They usually wait for other auklets to take flight with them in order to have safety in numbers. When they are diving towards the sea they often weave back and forth in flight to avoid being an easy target for avian predators. When flying back to the colony they fly directly into their nest sites. Sometimes they circle above the colony, waiting for an opportune time to return. When predators are seen approaching, crested auklets make simultaneous panic flights in groups away from the colony as a way to alert the rest of the colony that a predator is nearby. Once caught by a predator, these birds fight back with aggressive bill-pecking, viciously scratching at their predators and beating their wings. Many of them are able to escape. Because most predation occurs during the day, some fledging of the chicks occurs at night when they are not as visible to predators (Jones 1993).
Known Predators:
Anti-predator Adaptations: aposematic
Crested auklets are monogamous, with high site and mate fidelity throughout their breeding lives (Hoyo 1996). They compete with others for high quality mates and the best nesting sites. The more dominant crested auklets typically have longer crest lengths than other auklets in the colony. Longer crest lengths are preferred when these birds are selecting a mating partner. During the breeding season, pair bonds are formed following elaborate courtship behaviors including stereotypical postural displays that increase in intensity as the courtship between a pair progresses (Jones 1993). Many pair-bonds that form join to breed again in future breeding seasons.
After the first breeders arrive, non-breeders and juveniles arrive 3 to 4 weeks later. Some crested auklets participate in extra-pair copulations later in the breeding season as a way to assess the reproductive success of possible future partners. Males have been observed attempting extra pair copulations at their staging areas through aggressively disrupting pairs in the process of courting (Jones 1993). They rush in and attempt to disrupt females that are about to mate with other males. Birds that are not yet adults, and that are not yet breeding will make finding a suitable nest site their first priority. Adult auklets that are ready to breed and form a pair-bond display their courtship readiness by using the ocean as their staging area. This “staging area” is an area on the ocean that the male’s birds use to perform their courtship displays. This performance helps them attract a mate that they can form a pair-bond with and hopefully breed with that year. Some individuals that are not breeding may engage in courtship activities with extra-pair auklets near the end of the breeding season when chicks are either incubating or during the chick-rearing stage. Once a breeding pair of crested auklets re-forms prior to laying an egg, the male will actively guard the female and follow her around.
The female initiates courtship as she approaches a male that is trumpeting and performing a display. Both birds perform stereotypical postural displays that further advance their courtship (Jones 1993). During these mating rituals the male’s pupil contracts and appears glassy. The female stares intensely into his eye and then begins to touch the male’s facial areas with her bill. As long as the male doesn’t reject her, she will continue to court the male. Courtship between this pair continues with mutual cackling vocalizations along with intense billing, nibbling of male’s bill by the female, and burying bills in the nape and neck feathers of each other (Jones 1993). Both birds will touch each other with their bills and exhibit “ruff-sniff” displays toward each other. The climax of courtship is reached when the two begin neck twisting and then copulation begins.
Copulation in this species only occurs at sea. Copulation on water presents several issues including the possibility of loss of sperm during transmission if the female’s cloaca comes in contact with ocean water. During copulation, the male will look out for “scrums” in which several auklets will rush in and attempt to join/break up the mating. The male will actively defend his mating partner by chasing others off by using bill stabs against them.
Mating System: monogamous
The breeding season for crested auklets begins around May and lasts through mid-June. Timing of snow melt plays an important role in when exactly they begin breeding (Jones 1993). They lay a clutch size of one egg per breeding season and both parents are responsible for care of the chick. Most pairs will return to the same nesting site year after year unless a divorce occurred. Hatching is synchronous, with about 80% of the eggs hatching within a span of 10 days (Jones 1993). On average chick rearing lasts for about a month, sometimes longer; and they grow at a rate of 11 to 13 grams per day. Young do not fledge until they are close in body mass to their adult size. Several days before fledging young leave the nest site for awhile to start stretching out their flight muscles, referred to as “helicoptering” behavior. Little research has been done on the age at which young reach sexual maturity and can begin breeding. A few studies suggest that they begin to breed around three years old.
Breeding interval: Crested auklets breed once annually.
Breeding season: Breeding occurs from May through June and breeding time is strongly affected by snowmelt timing.
Average eggs per season: 1.
Range time to hatching: 1 to 2 months.
Average time to hatching: 1 months.
Range fledging age: 1 to 3 months.
Range time to independence: 1 to 3 months.
Range age at sexual or reproductive maturity (female): 3 to 4 years.
Average age at sexual or reproductive maturity (female): 3 years.
Range age at sexual or reproductive maturity (male): 3 to 4 years.
Average age at sexual or reproductive maturity (male): 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Chicks are precocial at the time of hatching. Both crested auklet parents participate in caring for young. Both incubate the egg and spend the night in their nest together. It is not yet known if parents help young during hatching. For the first day young are brooded continuously and both parents continue to brood for the fist week after hatching. Males brood young more than females do. After hatching, at least one of the adults will spend the first ten nights with their chick until they are able to thermoregulate themselves. After this occurs the chick can be left by itself in the nest if necessary.
Adults must forage for food for themselves and their chicks. They carry food in a sublingual pouch and feed the chicks one to four times a day. Females take more responsibility for feeding chicks than do males. After foraging for food, parents stay with the chick for about 5 to 10 minutes in the nest and feed it at regular intervals. Nests are kept clean and young do not defecate in the nest.
Parents care for their young from 1 to 3 months depending on where their colony is located. Chicks begin fledging when close to their adult mass. A few days before fledging they begin leaving the nest and stretching their muscles for flight. When ready they depart from the colony by taking flight from a boulder in attempt to fly towards sea where the risk of predation is extremely high.
Parental Investment: precocial ; 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 crested auklet (Aethia cristatella) is a small seabird of the family Alcidae, distributed throughout the northern Pacific and the Bering Sea. The species feeds by diving in deep waters, eating krill and a variety of small marine animals. It nests in dense colonies of up to 1 million individuals in the Bering Sea and the Sea of Okhotsk. It often breeds in mixed-species colonies with the least auklet, a smaller congener.
The species is known for its sexual ornaments, found in both males and females. These include colorful plumage with a forehead crest, a striking scent recalling citrus fruit, and a loud trumpet call, all of which appear to have evolved through sexual selection. The total population is around 6 million, almost half in North America. It is in general considered to be of least concern, though the Alaskan population faces additional threats from predation and oil spills.
The crested auklet was first described as Alca cristatella in 1769 by the German zoologist Peter Simon Pallas.[2] The specific epithet cristatella is Neo-Latin for "little crested" from Latin cristatus "crested" or "plumed".[3] It is now placed in the genus Aethia that was introduced by the German naturalist Blasius Merrem in 1788.[4] The genus includes four auklet species. There are no recognised subspecies of the crested auklet.[5] Within the genus. it is most closely related to the whiskered auklet (A. pygmaea).[6] The family Alcidae consists of many species of shorebirds including other auklets (not in the genus Aethia), puffins, razorbills, guillemots, and murres.[7]
The crested auklet can measure 18–27 cm (7.1–10.6 in) in length, 34–50 cm (13–20 in) in wingspan and weigh 195–330 g (6.9–11.6 oz).[8] They have a reddish-orange and yellow tipped bill, yellowish white irises, and white auricular plumes from their eyes to their ears. Their bodies, wings, and tails are primarily dark sooty grey, while their legs and feet are grey and claws black. The males and females are very similar, although the females have slightly smaller and less curved bills, additionally slightly smaller crests.[9]
Crested auklets are known for their forehead crests, which is made of black forward-curving feathers. These forehead crests are highly variable, and can have between two and twenty three narrow forward curving feathers. The average auklet has 12 crest feathers, which are of variable length, between 8.1 and 58.5 millimetres.[10] Auklets have auricular plumes and a bright orange bill with curved accessory plates.[11] Like forehead crests, these features vary widely within auklet populations.[9]
The crested auklet is recognized primarily by two characteristics during the breeding season. The first is its crest, a group of bristle feathers located on top of its head above its eyes. The second is a social odor that the auklets produce during the breeding season, described as smelling like tangerines. This odor originates from tiny wick feathers, located in a small patch of skin between the shoulder blades.[12] In winter plumage, their bills are smaller and dull yellow. They lack accessory plates and their crest and auricular plumes are reduced.[9]
Juveniles are similar to winter adults, but without auricular and crest plumes. Their bills are smaller, and colored a dull brownish yellow.[9] Juveniles take 33 days to reach adult size.[13]
Crested auklets are found throughout the northern Pacific Ocean and Bering Sea. They are particularly prevalent during the non-breeding winter months along the Aleutian Islands, Kuril Islands and the Russian island of Sakhalin. They travel to breeding locations on the islands and shorelines of the Sea of Okhotsk and the Bering Sea during the late spring and summer.[1] Their habitats consist of slopes, boulder fields, lava flows, and sea cliffs. They are often found with other auklet species such as the least auklet.[9] On a daily basis, crested auklets circle 500 meters above the sea and the breeding colonies. This circling is triggered by disturbances and predators posing a threat.[13]
Crested auklets primarily forage in deep waters, however sometimes in areas closer to the shore, but always in large flocks. Little is known about the winter diets, however, it is suggested that they feed on a variety of marine invertebrates. Crested auklets are planktivores. Their diet consists mainly of krill, but they are also known to eat copepods, pteropods (such as Limacina), amphipods and larval fishes.[9] Crested auklets dive from the surface of the water to catch their food. This behavior has been described as underwater "flight".[14]
The crested auklet breeding season begins mid-May and ends mid-August.[15] Their nesting sites are within the rocky crevices of North Pacific coast. They breed in dense colonies of up to one million birds. Because of this, nesting sites are in close proximity, with as little as 0.3 meters between nests. Even so, there is a high degree of territoriality, and adults show a high degree of site fidelity within a year.[16] Because mating occurs at sea and males have no copulatory organ, males must hover over females for a successful mating. Mate choice is mutual, but females do have final choice on breeding partner.[12]
Crested auklets are highly social during the breeding season, before pair formation, and after pair formation. Within a breeding year, however, crested auklets are monogamous, with only 10% of the population having extra-pair copulations. Partners continue to self-advertise to other birds when they are not incubating. While some of this advertising behavior can be linked to extra-pair mating, it is suggested that continuation of the behavior allows birds to find pairs for the next breeding season. Only 45.5% of birds remain with the same partner in the subsequent breeding season.[12]
Both sexes invest highly in parental care; parents share equally in incubating the single egg and raising the chick. Since both sexes are ornamented, crested auklets align with Robert Trivers's parental investment theory, which predicts that with biparental care, mutual choosiness will arise.[17]
Crested auklets are unique in their use of optical, vocal, and olfactory signals in mating. Their communicative behavior is more complex and diversified than that of closely related species. There are three general evolutionary mechanisms proposed to address the origin of the elaborate display traits of crested auklets, and of showy mating signals by males in general:
Asserted dominance, with regards to claimed display area, has been correlated with crest length in both males and females. The existence of these showy monomorphic traits is indicative of intense sexual selection for both sexes. Large-crested adults of both sexes receive higher levels of sexual interest and displays from the opposite sex compared to those with smaller crests.[10] Crested auklets with larger crests are more likely to obtain mates and to form pair bonds earlier.[10]
Based on divorce rate and mortality, more than half of individuals find a new mate each year.[11] Female crest length is the primary factor of male mate switching between years.[21]
While there is variation in displays across populations, crested auklet crests and plume ornaments are consistent in expression within an individual over time. Furthermore, there is little sexual dimorphism or evidence of condition dependence. From studies, it seems to be a survival-neutral ornament.[15] Some studies, however, offer up a functional purpose for these ornaments. One study suggests a link between habitat complexity and facial feathering, where tactile facial elongation helps individuals navigate complex underground crevices.[22] The high density of crested auklet nesting sites can be expected to impose selective pressures on sensory mechanisms.[22]
Crested auklets have a wide variety of single and complex calls. Billing is "defined as pair courtship with mutual cackling vocal display." It is a crucial part of successful pair formation and becomes harmonious once male and female partners are well acquainted.[12] Trumpet calls are one of the most common advertising calls. The call represents a complex but stereotyped vocal sequence that is linked with a specific visual display.[16] Between individuals, the calls differ in duration and frequency. Calls are primarily performed in males, but can also be seen in females. The call is particularly strong in widowed females.[12] These calls stay stable from year to year, and individuals' specific calls are associated with the maintenance of long-term social bonds between pair mates and between neighbors. This suggests that trumpet calls can be used for both short-term and long-term individual recognition. Recognition of neighboring individuals' calls is advantageous because it minimizes energy expenditure on aggressive displays, and prevents conflict between neighbors and trusted individuals (the "dear enemy phenomenon").[16]
Crested auklets have a distinctive citrus-like plumage odor. The scent is released when there is ruffling of feathers on the nape and upper back of the individual from threat, trumpeting, or billing displays. The cloud of scent released encourages the ruff sniff display. A ruff sniff display is when birds fully insert their half open bill into the other's plumage. This display occurs in the absence of obvious aggression and is important for pair formation.[12] For both sexes, a strong odor attracts more individuals, which then do a ruff sniff display.[21]
Odor secretions increase during the breeding season, highlighting its association with courtship and mate selection. The scent may also act as an ectoparasite repellent.[23] This scent is also found in whiskered auklet.[13]
According to the International Union for Conservation of Nature, crested auklets are of least concern.[1] The global population exceeds 8.2 million individuals, while the North American population is estimated at 2.9 million birds. However, an accurate assessment of the number of birds is difficult, since those on the surface of the colony and in the nearby sea form only a small proportion of the variable and poorly understood population.[1]
There is greater concern for the Alaskan population. There has been high predation by rats which have escaped from fishing vessels in the harbor. The auklets' main predators are gulls, Arctic fox and common ravens. They have also been reported in the stomachs of halibut caught on St. Lawrence Island. Oil spills and collisions with light sources pose additional risks. In Alaska, there is some subsistence hunting of the species.[14]
The crested auklet (Aethia cristatella) is a small seabird of the family Alcidae, distributed throughout the northern Pacific and the Bering Sea. The species feeds by diving in deep waters, eating krill and a variety of small marine animals. It nests in dense colonies of up to 1 million individuals in the Bering Sea and the Sea of Okhotsk. It often breeds in mixed-species colonies with the least auklet, a smaller congener.
The species is known for its sexual ornaments, found in both males and females. These include colorful plumage with a forehead crest, a striking scent recalling citrus fruit, and a loud trumpet call, all of which appear to have evolved through sexual selection. The total population is around 6 million, almost half in North America. It is in general considered to be of least concern, though the Alaskan population faces additional threats from predation and oil spills.
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