Частота встречаемости клубных пар большой конюги (Aethia cristatella) при высокой и резко снизившейся численности птиц в колонии.

The crested auklet is a medium-sized planktivorous seabird of the Alcidae family with complex social behavior, one of the interesting forms of which is the formation of club pairs in addition to existing breeding pairs. The occurrence of club pairs in this species was studied on the Talan Island (Sea of Okhotsk) in 1988-1989, when the colony was in a good condition, and in 2008-2015, when its population decreased several times. The research showed that the proportion of individuals with club partners is higher in a high-population period (35 %) and lower in a low-population period (18 %); the differences, however, are not significant. In both study periods, from 73% (1988-1989) to 80 % (2008-2015) individuals were consistent in following the chosen strategy of forming or not forming club pairs for at least two seasons. The presence of club pairs seems to facilitate the change of mate in the next breeding season, but club mates then become partners relatively seldom.

Частота встречаемости клубных пар большой конюги (Aethia cristatella) при высокой и резко снизившейся численности птиц в колонии.

The crested auklet is a medium-sized planktivorous seabird of the Alcidae family with complex social behavior, one of the interesting forms of which is the formation of club pairs in addition to existing breeding pairs. The occurrence of club pairs in this species was studied on the Talan Island (Sea of Okhotsk) in 1988-1989, when the colony was in a good condition, and in 2008-2015, when its population decreased several times. The research showed that the proportion of individuals with club partners is higher in a high-population period (35 %) and lower in a low-population period (18 %); the differences, however, are not significant. In both study periods, from 73% (1988-1989) to 80 % (2008-2015) individuals were consistent in following the chosen strategy of forming or not forming club pairs for at least two seasons. The presence of club pairs seems to facilitate the change of mate in the next breeding season, but club mates then become partners relatively seldom.

Bird and Mammal at-sea Distribution Along the North-East Passage off Siberia

Quantitative seabird and marine mammal at-sea distribution was determined along the North-East Passage, off Siberia, in August 2017. A total of 18,400 seabirds were tallied during 340 transect counts, belonging to 31 species. Some bird species were numerically dominant: fulmar Fulmarus glacialis, Brünnich’s guillemot Uria lomvia, shorttailed shearwater Puffinus tenuirostris and crested auklet Aethia cristatellea representing more than 90 % of the total. Humpback Megaptera novaeangliae and bowhead whales Balaena mysticetus formed the bulk of the 100 large whales, as well as 40 white-beaked dolphins Lagenorhynchus albirostris, concentrated in a major hotspot. Two species represented 97 % of the 910 identified pinnipeds: harp seal Phoca goenlandica and walrus Odobenus rosmarus. Polar bear Ursus maritimus was detected as 75 individuals, while more than 3,500 were noted on Wrangel Island, out of effort. The major factors affecting top predators’ quantitative distribution were the geographic differences between seas, and the importance of a major hotspot for humpback whales and harp seals.