Mass migration of Birds of Prey in North and Central Ukraine in mid-October 2011

February 22nd, 2012 Posted in Field researches, Migrations, Photos

We already mentioned at our web-pages, that migration intensity of birds of prey significantly differs for various regions of Ukraine. However, numbers of migrating raptors can be also greatly impacted by weather conditions, forming migration waves. It is the phenomenon which we observed in mid-October 2011.

MIGRATION OF BIRDS OF PREY ALONG KYIV RESERVOIR

15 and 16.10.2011 we observed migration of birds of prey at one of our observation stations located to the north from the village Lebedivka (Vyshhorod district of Kyiv region) at the shore of Kyiv Reservoir. On 15 October it rained until 11 a.m., alternated with hail. Only when it stopped and the sky was getting clear, we saw single Buzzards and their pairs. Gradually, the number of birds in groups became higher, and in the afternoon the sky was full of migrating raptors.

At first, bird groups flew to the south-west, then to the south and to the end of the day the migration mass of raptors were moving to the east and south-east. The birds, which chose the latter direction, flew from the reservoir; we saw about 400 of them and for many years of observations we recorded such direction of passage for the first time. One of Buzzard’s flocks included 212 birds. Big flocks of these birds stretched for several kilometres.
We intentionally selected this territory to study migration of birds of prey. A vast area of the reservoir stretched from the north to the south makes migrating birds to keep to the left bank during their autumn passage. Thus, raptors fly around the water obstacle and form a narrow stream of migrants. Besides, after the cold spell numerous birds actively left northern territories.

As usual, we also did catching and ringing of birds of prey. We captured 2 Goshawks – adult and young.
On 16 October the weather was sunny, in the morning we saw ground frosts. The raptors migration was short and scanty. Birds flew from 09.30 to 11.20.
We have never seen in Polissia such numbers of migrating birds as it was on 15 October.

On 15 October we counted:
Buzzard – 1037 птиц; Hen Harrier – 24 (including 2 adult males); Pallid Harrier – 1 adult male; Sparrowhawk – 88; Goshawk – 3; Spotted Eagle – 1; Common Kestrel – 2.

On 16 October we counted:
Buzzard – 203; Hen Harrier – 1; Sparrowhawk – 11.

Sergey Domashevsky, Yury Demidenko

MIGRATION OF BIRDS OF PREY ALONG KREMINCHUH RESERVOIR

In the morning of 16 October 2011 we didn’t expect an active migration of raptors: air temperature was only +3oС, the sky was cloudy, a strong north wind blew. By 9 a.m. the fog had fallen at the altitude of about 50 m above ground. However, first several Buzzards flew at a low height immediately after the sunrise, and about 10 a.m. we recorded single Buzzards and their groups up to 5 individuals migrating at the edge of the fog – up to 50 m altitude. Sometimes they disappeared from the field of view, making a small turn. About 11 a.m. the fog slightly rose and the passage became more obvious – we saw groups of Buzzards up to 15 ind. Having made by that time bird counts at ponds near the village Irkliiv (Cherkasy region) we moved for some km to the point convenient for observations of migratory birds at the shore of Kreminchuh Reservoir. Gradually the fog cleared away and raptors flew abundantly. From 12.00 to 13.00 Buzzards flew as almost a continuous stream, only sometimes delaying in thermals. Together with them Sparrowhawks migrated, single individuals of other birds of prey were also recorded. Often it was impossible to distinguish separate flocks, and we sorted them out only according to time of their passage or as more concentrated groups of birds. Such groups included from 20 to 120 birds. From 12.00 to 13.00 over 1,000 birds flew, i.e averagely 170 Buzzards were passing the observation point each 10 minutes. After that, during each two hours of observation about 600 Buzzards passed. We stopped observations at 15.20 though the migration was still going on.

In total, we counted more than 2600 Buzzards, 119 Sparrowhawks, 4 Goshawks, 7 Hen Harriers, 1 Rough-legged Buzzard и 2 Black Kites.

Such a late meeting of two single kites was еspecially interesting, we took a good look of them, and there’s no doubt in accuracy of their identification. All the birds migrated along the shore of Kremenchuh Reservoir to the west and north-west, which is a typical direction of raptor’s autumn migration in this area since they aim to fly around the water area of the reservoir.
All migrating Buzzards according to their phenotype belonged to nominative subspecies and had rather dark underparts. We also observed one individual of the Common Buzzard with an untypical coloration – from below the bird was almost white, slightly cream-coloured, only a dark craw and two small spots on a wing’s bend proved that it was the Buzzard. Sergey Domashevsky was lucky to take picture of a Buzzard of similar colouration to take picture of a Buzzard of similar colouration.

We assume, that intensive migration of the Buzzards was explained by several factors: warm weather of September and the first half of October, and also a sharp fall of temperature before the beginning of migration. The concentration of birds along the shore of the reservoir played an important role as well.
Taking into account the communication by A.Stativa about intensive migration of raptors in Sumy region (15.10.2011 there were recorded 468 Buzzards), and the observations by S.Domashevksy in Kyiv region we can only suggest a general scale of Buzzard’s migration at that period. It is interesting, that westward, in Zhytomyr region (communication of I.Polyushkevich, 17.10.2011), there wasn’t recorded intensive migration of raptors; also any pronounced migration wasn’t observed in the east of Ukraine (pers. com. by V.Vetrov).
Basing on data of V.M.Galushin (1971) about breeding density of Buzzards, their breeding success and productivity we can conclude that for a couple of days Central and North Ukraine was crossed by the Buzzards which nested in the area of several tens of thousands square kilometres, apparently they were from north regions of Ukraine and adjacent areas of Russia.

Maxim Gavrilyuk, Alexandr Ilyukha

Post a Comment

*