Место издания:Institute of Marine Geology and Geophysics FEB RAS Yuzhno-Sakhalinsk
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Аннотация:It was recently suggested that Eastern populations of Arctic Warblers, breeding in the south of Kamchatka, Kuril Islands, Sakhalin, Hokkaido , Eastern Amurland and highlands of Sikhote-Alin Ridge, should be separated into a different monotypic species - Kamchatka Leaf Warbler, Phylloscopus examinandus Stresemann, 1913. This opinion was based on the analysis of DNA and specific “slow” type of song in the eastern birds.
In fact, birds from those populations show clear morphological variation and difference in body size between populations. Wing length (mm) of birds from Sikhote-Alin Ridge, Eastern Amurland, Sakhalin and Southern Kuriles is the shortest compared to other populations: males 65,0-73,3 (mean 68,9), females - 63,7-68,9 (mean 65,8). Arctic Warblers from the south of Kamchatka and north of Kuril islands are clearly bigger and long-billed. Wing length (mm) in males are 70,3-76,1 (mean 72,7), females - 69,1-72,6 (mean 70,9). Therefore, “slow singing” Arctic Warblers are forming two distinctive geographical races, the «examinandus» should belong to large birds from Kamchatka. Russian ornithologists are used to applying the name Ph. b. hylebata Swinhoe, 1860 for southern populations. Color features were described for this form by Swinhoe, 1860, and they clearly show the difference of the “slow singing” Arctic Warblers from nominative subspecies, and size in this description is clearly smaller than in birds from Kamchatka and Northern Kuriles. Therefore, eastern group of populations should be considered as two geographical races: southern small hylebata and larger northern examinandus. Reproductive isolation between “slow singing” Arctic Warblers and “fast singing” Ph. b. borealis, is typical for different subspecies but not for real species. Both song types were registered from the south of Yakutia and Transbaikalia till north of Sakhalin, and some males are using both types of songs, some males show “intermediate” song types. Colors of collections specimens from Sakhalin and Amurland reveal that in these regions “intermediate” features are common, and this populations are closely related to nominative subspecies, in contrast to populations from Kuriles. The North of Kamchatka adjusting to Kariak Ridge (part of Ph. b. borealis breeding range) is inhabited by Arctic Warblers with hybrid features of borealis and examinandus. These facts show us that separating “slow-singing” Arctic Warblers into another species is at least premature.