Status of cranes and storks breeding in the middle Amur River basin, Russia, in the summer of 1997

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The breeding status of sympatric Japanese Cranes Grus japonensis, White-naped Cranes G. vipio, and Oriental White Storks Ciconia boyciana was observed from the air in the middle Amur River basin in July 1997. In the area there were 113 G. japonensis (including 22 chicks, 19.5% of the population), 108 G. vipio (12 chicks, 11.7%) and 195 C. boyciana (46 chicks, 23.6%). There were 15 G. japonensis pairs with chick (s), amounting to 44.1% of the estimated number of pairs (n=34), and the average number of chicks was 1.5 per family. The density per observation hour was 10.7 G. japonensis in Muraviovka and 3.2-5.6 in other regions, a level that was only half that of the Japanese population. It appears that the presence of shallow ponds and streams for foraging is an important limiting factor for breeding cranes in the study area. Non-breeders were found more commonly in the regions near the main Amur River channel, indicating that there are considerable differences in habitat suitability from region to region. The estimated number of pairs of G. vipio was 24 and the average number of chicks was 1.5 per family. We did not see any G. vipio along the Zeya-Tom Rivers, but it was abundant in Muraviovka. The species seems to be very rare north of 50°N in this area, probably due to the scarcity of croplands. We discovered 48 C. boyciana nests and saw chicks in 24 of them. The average number of chicks was 2.1 per nest, ranging from 1.0 in the Khingan-c R to 2.0-2.3 in other regions. The breeding success of C. boyciana was low because of recent grass fires and unusually dry weather in the summer of 1997.
野生生物保護学会の論文

Status of cranes and storks breeding in the middle Amur River basin, Russia, in the summer of 1997

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