Materials for the Study of the Spring Migration of Waterfowl (Anseriformes, Aves) on the Lake Khanka

摘要

Abstract The results of 11?years (2003–2013) monitoring activities, including estimation of number and gender structure of waterfowl on the Lake Khanka, are presented. The accounting work (50?days) took place in the first decade of April, in the period of mass spring migration of migratory birds. About 682,270 birds are registered. The comparison of the species composition and the ratio of the major groups of waterfowl of the two periods — 2003–2009 and 2010–2013 are given. The most minority group of migratory birds is Cygnus — less than 0.1% of all registered birds. More than 10,000 specimens of geese were accounted (17.7% of registered birds). The maximum number of birds was registered in 2008, the minimum number was registered in 2011. In all years of monitoring the part of Anas formosa was the largest among migratory birds — from 42 to 80% of all registered birds. The Anser albifrons dominates among all Ansers — about 50–80% of all identified species of Ansers. For the first time of all years of the ornithological investigations of the Prikhankayskaya lowland the gender structure of Anas was identified by visual estimates and photo data. The sample was 28.9 thousand birds. The average proportion of males for all years (2003–2013) was 58.9%, the maximum was recorded for Authya ferina (70.2%) and Authya foligula (70.3%). Keywords Migratory birds ; Spring migration ; Waterfowl ; Species structure ; Gender structure prs.rt("abs_end"); Introduction As a habitat for waterfowl, Lake Khanka is included into the list of wetlands of international importance (Ramsar Convention). Anseriformes is one of the most mass group among other birds of this location, its largest number can be seen during spring migration. At this time well pronounced ways of transit migration cross the lake, it is a place for long-term feeding stops. Such stops are used to refill birds' energy supplies, which is necessary for further migration and coming breeding season. In Russian literature special attention is paid to quantitative and qualitative characteristics of Anseriformes' spring migration on the Lake Khanka ( Polivanova, 1971 , Polivanov, 1975 , Gluschenko and Bocharnikov, 1990 , Gluschenko and Bocharnikov, 1995 , Gluschenko et al., 1995 , Gluschenko et al., 2005 , Gluschenko et al., 2008 , Gluschenko et al., 2008 , Gluschenko et al., 2013 and Gluschenko and Mrikot, 2000 ). In this paper we are presenting more detailed data collected on this question in 2010–2013?years. We also compare obtained results with the similar ones for the period of 2003–2009, which were published earlier ( Bocharnikov et al., 2010 ). Current work summarizes 11?years of monitoring of this important for the region birds' group and to some extent the whole period of observation since 1987?year. The main observations during all these years were conducted in the places of Anseriformes' mass accumulation in the Russian part of the Khanka Lake according to methodology, which we described earlier ( Gluschenko et al., 1995 ). Methods Depending on a year observation took time from 3 to 6?days mostly during the first decade of April (in a period recommended for hunting of waterfowl, basically in locations, where hunting is strictly prohibited) ( Table?1 ). Table?1. Terms of spring surveys of Anseriformes on the Lake Khanka in 2003–2013?years. Year of observation Terms of conducted surveys Number of observing days 2003 2–5.04 4 2004 2–9.04 4 2005 6–9.04 4 2006 5–7.04 3 2007 31.03–4.04 5 2008 29.03–1.04 4 2009 3–6.04 4 2010 2–6.04 5 2011 7–12.04 6 2012 31.03–4.04 5 2013 7–12.04 6 2003–2013 29.03–12.04 50 Full-size table Table options View in workspace Download as CSV During these days of observation we visited the key places of ducks' and geese' spring stops. According to expert estimation based particularly on multiple aerial surveys, which we held in the Prikhankayskaya lowland in recent times, we took into account from 40 to 80% of various species of ducks and geese crowded at the period of survey in the Russian sector of Khanka. But the main locations of swans' stops were always out of our focus. Birds of this genus were registered only by chance and sporadic, so such observations don't reflect the whole way of their migration through Lake Khanka. While planning the work we set 3 main goals: following the perennial dynamics of ducks and geese population; reveal a percentage between numbers of different species of ducks and geese; study a gender structure in spring populations of ducks. As mentioned earlier, we have already published the results of annual surveys for the period of 2003–2009?years ( Bocharnikov et al., 2010 ). Thus in current paper we are presenting data only for the last 4?years (from 2010 till 2013), when in sum we registered almost 170 thousand of Anseriformes from 23 species ( Table?2 ).