Crested Auklets

One of the most charismatic, yet underappreciated birds on the planet has got to be the Crested Auklet (Aethia cristatella). Crested auklets are ridiculously goofy-looking birds during their summer breeding season.

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Most species of seabirds are pretty unassuming in appearance, with a standard palette of blacks, greys, white, and browns, and the sexes are frequently similar. -Part of the reason for this contrast with much showier avian groups like parrots and songbirds is because of the parental investment that seabirds engage in. Most species are long-lived and only raise one or two chicks a year. In Crested Auklets, both parents engage in parental care, often sharing incubation and feeding duties – although at least one study showed that CRAU males tended to brood and defend chicks more often, while females tended to forage and bring food back for the chicks more often. This serial monogamy means that there is no pay-off for the male bird to copulate with as many females as possible, as they all already have a mate, a brood, and it takes a lot of work to care for and raise the single chick.

Crested auklets, however, took a different approach and their appearance is directly a result of the evolution of their grand social system. These birds are highly social creatures who, during their summer breeding season, gather and nest in expansive colonies numbering into the tens and hundreds of thousands – often nesting with their congeners, Least Auklets. In order to find a mate (either old or new), establish territories (either old or new), and interact with neighbors, Crested Auklets rely on a highly diverse set of sensory cues. At first glance, say, from a picture, a person gets an immediate sense of their unique charm – a bright-orange stubby bill whose corners turn up as if in a friendly grin. And a perfect set of slender feathers curving up and over the bill as if styled into shape. And bright, perfectly round, white eyes that look like someone glued a set of googly eyes on.  Watch a video taken at a colony, and you’ll see and hear the colorful variety of yips, trumpets, barks, and duets, all the more intense when heard as the ambient noise of thousands of birds in the colony. You can watch as birds interact as parts of a pair – billing or preening each other – or as part of a group – scrumming, ruff-sniffing, etc.A37R3852

But there is one sense missed from not seeing these birds in person, and that is the scent. Crested auklets are one of the few avian species in the world that produces a scent. Certainly this is one of their most unique features. The scent has been described as “tangerine”. In reality it is impossible to describe or imagine. While it does have the qualities of a citrus smell, it is also in addition subtly acerbic, perhaps like a very mild ammonia cleaner. And it definitely smells “orange”. All in all, it is a pleasant scent, and one that really completes the Aleutian experience. On foggy mornings, waking up to the smell of crested auklets is always a fun reminder of just how special these islands truly are. And when sticking my face down into crevices to check nests, I could sometimes tell if a bird was there just by the presence of that characteristic smell.

CRAU nest crevice

CRAU nest crevice

After handling them my hands would smell of CRAU. While not a whole lot of research has been done on the scent, it is now known that the smell is produced by miniscule “wick feathers” around the nape region on the back of the neck., whose tips dissolve into a powder that distributes the smell. CRAU will also sometimes engage in alloanointing, where by rubbing themselves on other birds they share their specific scent with others, perhaps to reinforce social bonds between mates, crevice neighbors, and chicks. It is also supported that the odor serves as a repellent to avian parasites like ticks, fleas, and lice.

Crested auklets are true seabirds in the sense that they spend most of their life on the open ocean. The only time that they come to live on land is during the short summer breeding season, taking place between May and August. They breed in the remote and uninhabited western Aleutian Islands, as well as in the Pribilof Islands, in the Bering Sea, with a total of 43 known colonies in these areas. They can also be found nesting in Russia’s Kuril Islands, the Chukotski peninsula, and on islands in the Okhotsk Sea. The global estimate for this species is about 6 million. The birds nest in the crevices between boulders and rocks on talus slopes and sea cliffs, often returning each year with the same mate to the exact same crevice.

They lay only a single egg a year, incubating it for about 34-41 days. When it hatches, it takes the chick about 35 days to fledge. When foraging at sea for themselves and their chicks, the Crested Auklet diet consists of zooplankton – especially abundant krill species. In fact, all of the Aethia auklets feed on krill and other zooplankton, although resource partitioning does seem to take place on a microhabitat level in order to minimize competition. CRAU are pursuit divers, meaning they dive from the surface of the water and actively chase their prey underwater. They propel themselves underwater using their wings, in a kind of “flight”. Virtually all of the auklet colonies are located on volcanic islands adjacent to deep water where currents provide deep-water nutrients for plankton to bloom on the surface – creating high productivity for a variety of marine life.

Crested and Least Auklet flybys

Crested and Least Auklet flybys

While the population remains at a healthy number today, there are many threats to Crested Auklets. A large one, and one I covered in another post, is through the danger of introduced and invasive species. Possibly the worst introduced species posing a threat to seabirds (and endemic wildlife around the world) is the RAT. In the Aleutians, its the Norway rat which was brought over as a hide-away on fishing boats and shipping vessels. As soon as the boats docked on islands, the rats got out and bred, killing burrow-nesting seabirds by the thousands. Some islands are completely devoid of colonies due to the presence of rats, which will kill eggs, chicks, and adult birds indiscriminately. On Gareloi, which luckly was never invaded by rats, instead had Arctic foxes brought over and deliberately let go by Russians in the early 1900s. This was to keep the Aleutian fur trade going, which by that time saw the tremendous disappearance of fur-bearing mammals like sea otters and fur seals nearly eradicated due to ravenous hunting. By 1991, under management from US Fish and Wildlife, the foxes were successfully eradicated from the island. Within several years, seabirds started returning to the island and establishing thriving colonies. Today, Gareloi has some of the largest Crested and Least Auklet colonies in the Aleutians. Parakeet Auklets are also establishing strongholds, although Whiskered Auklets are still yet to be seen. Storm-petrels are also making a come-back, with the first nesting Fork-tailed Storm-petrel found by Professor Ian Jones in 2014, and several more by myself and the other Gareloians this year. While Gareloi was completely silent at night compared to Buldir, we did have a few nights this year where we heard flybys of Leach’s and Fork-tailed Storm-petrels.

Another big threat to CRAU are oil spills. There is a relatively large amount of ship traffic passing by the Aleutians and a wreck and spill would be massively devastating, due to the high density of nesting birds. Entire colonies could be wiped out.

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Crested auklets are by far one of the coolest seabirds that I have had the pleasure to work with, and I hope that this season in the Aleutians was not the last time I that will be seeing their pretty faces.

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