High numbers of waterbirds and raptors at Medvedce Reservoir (NE Slovenia) during a weather disturbance in October 2012

Weather significantly influences bird migration, even though its effect is often difficult to assess and quantify. Several records of scarce or rare birds in Slovenia have been linked to adverse weather conditions. Between 26 and 29 Oct 2012, the weather in Slovenia deteriorated with a decrease in average temperature from around 10 degree C to around 0 degree C, strong northerly winds and ample precipitation. There was also some snow in the lowlands. On 29 Oct 2012, the weather at Medvedce Reservoir (UTM WM53, NE Slovenia) was cloudy, a northeasterly wind was blowing and there was some snow, which was melting quickly. A total of 11,279 birds were counted, which exceeds the second highest count at the Reservoir by 3000. The highest daily totals for the Reservoir were counted for Wigeon Anas penelope (457), Gadwall A. strepera (150), Teal A. crecca (1461), Pintail A. acuta (183), Cormorant Phalacrocorax carbo (372) and Golden Plover Pluvialis apricaria (121). The total for Gadwall is the highest ever recorded in Slovenia, while totals for Teal, Pintail and Golden Plover are the highest recorded in Slovenia during autumn migration. On the same day, unusually high numbers of waterbirds were observed in nearby Austrian Styria as well.