Scientific name: Aethia pygmaea
Alternate name: Pygmy auk
Aleut: Choochirrech; Toochmuch
Japanese: Shirahige-umisuzume (White-whiskered Sea-sparrow)
Russian: Tartorka; Turutura (Chatterbox); Petushok (Rooster); Malinka Konjuga (Small Crested Auklet)

Spaces between beach boulders, talus slopes and cliff crevices of the western Aleutians, the Komandorskie and Kuril Islands harbor the nests of the Whiskered Auklet. It is perhaps the prettiest but, unfortunately, the least known and least populous of all the auklet species.

Although the species has been known to range during the winter months to seas surrounding southern Japan, it tends to remain resident all year in its limited breeding range, and some reports indicate that it may shelter within its breeding cavities during winter storms.¹⁵⁴ It is a rare visitor to St. Lawrence Island in the North Bering sea.¹⁸⁷

Even within its breeding range the Whiskered Auklet is not abundant. It is said to be common on Mednyi of the Komandorskie Islands, and about 1,500 breeding pairs associate with other auklet species on Buldir Island in the outer Aleutians.¹¹⁵ There are an estimated 20,000 Whiskered Auklets in the outer Aleutians.⁵⁷⁰ No estimates are available for the rest of the breeding range, but its total numbers may reach only about 50,000 to 80,000. Further explorations may reveal slightly greater numbers in the future, but there is also reason to believe that more accurate counts may produce a lower figure.

Earlier literature has given the impression that the Whiskered Auklet is secretive in its habits and that its behavior is difficult to observe. However, recent accounts indicate that this species is no more reclusive than the other auklets and that one needs only to be in the right place at the right time of its breeding season. Photographs accompanying this chapter show that the Whiskered Auklet does rest and display in the open among other auklet species. At sea, however, where it sometimes congregates in groups of up to three hundred birds, it does not appear to associate with other auk species. More usually small groups of eight to ten birds are seen feeding together in the tide rips.¹¹⁶

In breeding plumage the bird displays a slate-gray back, rump, and upper tail, with darker wing and tail feathers. White ornamental plumes decorate the forehead and spray from the cheeks and behind the eye. Narrow black plumes curve forward on the front of the head. The throat is gray-brown, as are the breast and flanks which merge into white on the belly and undertail coverts. The bill is red with a pale bluish-white tip and the feet and legs are bluish-gray. The eyes of an adult have white irises.

Mating activity probably takes place on the water, as it does in several other alcid species. Some courtship has been observed on slopes near the nest cavities in late May, and some displays undoubtedly continue within the confines of the nest. To date, no one has described the bird's behavior in detail or compared it carefully with other species, although limited information had been published from observations on Buldir Island where they nest in mixed colonies with Crested and Least Auklets among the talus.³³⁶

An adult Whiskered Auklet averages 192 millimeters in body length, the female being a little larger than the male. The wings of twenty-three males averaged 108 millimeters while eight females averaged 109 millimeters. Aleutian birds tend to have smaller body dimensions than the Kuril populations, while the Komandorskie birds are of intermediate size.¹⁸⁷ On Buldir Island between 1 June and 10 August 1974 and 1976, Vernon Byrd's group weighed sixty adult birds.116, 152 These showed a range of 102 to 137.5 grams and averaged 120.7 grams in body weight.

The single egg is laid in a slight depression on bare soil or preferably, on fine gravel in a cavity among the rocks above the high tide zone and in talus slopes.³³⁶ The egg weight is unknown but is estimated to be between 30 and 36 grams. On Buldir their eggs are deposited during the first week of May to June and hatch between the last week of June to 8 July. The incubation period is approximately 35 to 36 days.³³⁶ The egg is ovate in shape, dull white, smooth and without luster.⁶⁴ Four chicks, weighed on their hatching day, averaged 19.8 grams in weight and were covered with thick black down merging to gray on the abdomen. Most chicks have fledged by 15 August 116 and a small sample showed 86 percent reproductive success.³³⁶

The Whiskered Auklet feeds on zooplankton consisting of gammarids, amphipods, and copepods. A few small fish may be eaten and some stomachs have contained mollusk eggs. During the breeding season at Buldir Island they feed mostly on a small copepod Neocalanus plumchrus which they harvest close to shore in tidal rips and upwellings.¹⁵² The bird undergoes a complete postbreeding molt which includes the horny sheath covering of the bill. The spring molt is incomplete. During the winter the Whiskered Auklet usually stays close to their breeding areas. Here they are seen to associate at sea in small groups or in pairs diving frequently for food.

The usual predators of auks such as the fox, falcon, and eagle are not a particular menace to the Whiskered Auklet population. The islands in the outer Aleutians where the larger colonies of Whiskered Auklets are found have not been used for fox farming and although falcons may take a few, the more populous species are most frequently preyed upon.