Ecological and Geographical Structure and Dynamics of the Autumn Migration of Passerine Birds on the Putorana Plateau

The ecological and geographical differentiation and dynamics of the autumn migration of passerine birds on the Putorana Plateau are analyzed. In 1988–2004, eight sites were surveyed in the western and central parts of the region in an area of 150 000 km². The route census method was used. The passerine fauna of Putorana during the autumn migration period includes 42 species. Birds fly along a narrow shore forest-edge strip on the banks of large rivers or lakes in the southern, southwestern, or western directions. There are species distributed everywhere (n = 16; 38%), locally (n = 9; 22%), and pointwise (n = 17; 40%). The bird population density is 239–643 (on average, 440 individuals/km², n = 8). The population density of passerine birds during autumn migration is maximal in the south of Putorana, lower in the middle part of the region, and minimal in the north of the plateau. At multiday observation points, the population density was 420–796 individuals/km² on the days of most intensive flight (on average, 608 individuals/km², n = 2). Passerine birds fly at 8°–12°. For most species, the average duration of the entire autumn migration is 20–26 days; the average duration of their main migration is 7–12 days. The vast majority of individuals of almost all migratory species are united into monospecific and polyspecific flocks. The configuration of the autumn migration is a combination of four waves with four well-defined maxima. The most significant bursts of migration activity are associated with a decrease in air temperature and the absence of precipitation. The bulk of individuals of different species of the same genus or family usually migrate on different days. Synchronization of waves of peak migration is rare in related species. The community is numerically dominated by the Arctic warbler, common redpoll, and little bunting.