Seabirds Breeding in Open Nests on the Yamskie Islands (Sea of Okhotsk): Numbers and Distribution

详细

Abstract—The Yamskie Islands archipelago is regarded as a key marine bird area of global importance and since 1982 has been part of the Magadanskii Nature Reserve. The first survey of seabird numbers was conducted there in 1974 by A.G. Velizhanin. So far, his data for the Atykan, Baran, and Khatemalyu islands remain the only available information. On August 3, 2016, full photo surveys of the colonies of seabirds on these islands were carried out. The species list of all three islands includes six seabird species breeding in open nests: the Northern Fulmar, Pelagic Cormorant, Slaty-backed Gull, Black-legged Kittiwake, and Common and Thick-billed murres. Breeding of six auklet species in hidden nests and screes was confirmed: the Spectacled Guillemot, Tufted and Horned Puffins, Parakeet Auklet, and Crested and Least Auklets. The total numbers of seabirds nesting on Atykan, Baran, and Khatemalyu islands amount to more than 305 900, 103 500, and 102 000 individuals, respectively. In comparison with the previous counts, the following numerical trends have been noted. Considerable growth in the abundance of the Northern Fulmar on Atykan and Baran islands, the expansion of this species to Khatemalyu Island, and its presently high numbers on this island have been observed. The nesting population of the Black-legged Kittiwake has grown on all islands by more than twice. The abundance of the Pelagic Cormorant, which is the rarest species on the archipelago, has grown on Baran and Khatemalyu islands, which are both located closer to the mainland, with the first nests having already appeared on the most remote Atykan Island. A growing abundance of murres is noted only for Atykan Island. The stable numbers of murres on the small Baran and Khatemalyu islands possibly reflects the maximum saturation of nesting rocks accessible to murres.