Characteristics of visible autumn migrations of waterfowl in national park «Prypiat-stokhid» in 2012-2017

Abstract

Introduction. There are 2 Wetlands of International Importance and 2 International Bird Areas on the territory of the National Park «Prypiat-Stokhid». Waterfowl are the main group of birds in wetlands. The study of bird migrations is important for the management of wetlands and the development of conservation measures to preserve the main routes of their migration, stops for rest and food. Therefore, at one of the Wetlands of International Importance (Prypiat River floodplain), which coincides with the International Bird Area (Prypiat River valley), the following research was initiated in 2012.

Purpose. The purpose of our research was to find out the peculiarities of autumn migrations of birds, which is necessary for the management of Wetlands of International Importance and International Bird Areas.

Methods. Our research were conducted at left bank of the Prypiat River near Svalovychi village in Liubeshiv district, Volyn region of Ukraine in September and October 2012-2017 (N 51°52' E 25°39'). Visible autumn migrations were studied according to conventional method with some of our changes and additions. Observations were performed visually, starting in the morning half an hour before sunrise and ending in the evening half hour after sunset (all hours of the light part of a day, without interruption). The light part of a day was divided into hour of observations, taking into the daily changes of sunrise and sunset (observation time decreased daily by 1,5-2 min). All observation hours were complete (a full hour), except last before evening hour which was incomplete (less or more than 1 hour). Flight altitude was determined visually, and flight directions – by 8 rhumbs. The width of the accounting corridor for different species of waterfowl ranged from 500 to 1000 m (250-500 m to the left and right of the observation point). All data on the number of account birds of each species, altitude and direction on their flight during the observation hour were recorded in a notebook. Species were determined visually and by voice. The binoculars were used during observations of migratory birds. The photographing was sometimes used to count the number of birds in large flocks and to identify species. In addition, the time of precipitation and wind directions were registered in observation hours. The weather data from local meteorological station was used and analyzed.

Results 4290 individuals of 17 species of waterfowl belonged to 4 bird families (Gaviidae, Podicipedidae, Phalacrocoracidae and Anatidae) and 4 orders (Gaviiformes, Podicipediformes, Pelecaniformes and Anseriformes) were counted there during our observations in autumn 2012-2017. Anseriformes were the most numerous migrants among orders of waterfowl (in average of 96,0 % from all counted birds), the number of birds in other orders were minor. The most numerous migrants among waterfowl were the Mallard Anas platyrhynchos (in almost all years of observation, in average 41,0 %) and in some years – Greylag Goose Anser anser and White-fronted Goose Anser albifrons (according to 24,1 % and 12,5 %), less numerous, but were among the most numerous species in some years – Wigeon Anas penelope, Cormorant Phalacrocorax carbo and Teal Anas crecca. Six species of waterfowl were observed in autumn migration annually (Greylag Goose, Mute Swan Cygnus olor, Mallard, Teal, Wigeon, Garganey Anas querquedula), some species – in most years of our observations (Cormorant, White-fronted Goose, Shoveler Anas clypeata) and others in some years only. Majority of waterfowl flew during 4 first morning hours (52,3 % of all counted waterfowl, among them almost all Mute Swan, prevalent majority of the Mallard, Garganey, and Wigeon) and 3 last evening hours (27,3 %, among them majority of the Teal, White-fronted Goose and Greylag Goose). Some species of this bird group flew in different observation hours of light part of a day (Cormorant and Garganey). The main direction of their autumn migrations was to the west (75,9 %, among them almost all geese, prevalent majority of the Teal, Garganey, Mallard and Wigeon), less – to the southwest (13,8 %, among them majority of the Shoveler) and very few in other directions. Prevalent majority of waterfowl flew at altitudes of 50-250 m (76,4 % of all counted birds) or most of them at altitudes above 100 m (55,7 %, among them majority of the Greylag Goose, White-fronted Goose, Cormorant and Shoveler). More a third of the Greylag Goose and White-fronted Goose and the insignificant part of the Wigeon flew at altitude over 250 m. Most of the Garganey, Wigeon, Mute Swan and Mallard flew at altitude between 50 and 100 m. Migrations of waterfowl at altitudes below 50 m were negligible (9,3 % of all waterfowl, among them prevalent majority of the Teal and more then a third of Cormorant and Mute Swan). Migratory birds were flying at higher altitudes when headwinds and crosswinds prevailed. The increase in the number of migratory birds coincided partly with the decrease in air temperature (up to +2º C and below 0º C). Wind directions did not significantly affect the flight of waterfowl, but its passage almost not observed during strong winds (more then 7-8 m/sec). 3 rare species of waterfowl fly through this territory in the autumn: Lesser White-fronted Goose Anser erythropus and Pochard Aythya ferina are listed in the Red List IUCN (International Union for Conservation of Nature) with global category – Vulnerable and Lesser White-fronted Goose and Goldeneye Bucephala clangula are listed in the Red Data Book of Ukraine).

Originality For the first time on the territory of the National Park «Prypiat-Stokhid», visible autumn migrations were studied and their peculiarities were clarified.

Conclusions. According to the results of 6-years research, the peculiarities of visible autumn migrations of waterfowl have been clarified. A small number of migratory waterfowl were observed during our research in autumn 2012-2017. However, the observation there of 3 (2 globally) rare species of waterfowl confirms the importance of this area for them and other species of migratory birds. The results of our research are the basis for the further study of migratory waterfowl, planning and implementation of conservation measures in this National Park, Wetlands of International Importance «Prypiat River floodplains» and International Bird Area «Prypiat River valley».