Arkadiusz Sikora, Krzysztof Wasielewski
Ornis Polonica 2015, 56: 76–87
https://doi.org/10.12657/ornis.2015.2.1
Abstract: In 2007–2014 within the area of SPA Lower Vistula River Valley near Gniew exceptionally large flocks of migrating birds were observed, including Eurasian Golden Plovers Pluvialis apricaria – up to 11,000 ind., Northern Lapwings Vanellus vanellus – up to 10,000 and the Eurasian Curlews Numenius arquata – up to 950 ind. Autumn migration was more intensive and lasted for longer than the spring one. The earliest Eurasian Golden Plovers arrived in mid-July, the peak of adult birds fell between late August and mid-September. The biggest concentrations have been regularly noted in 2nd half of October, while in November–December numbers clearly declined. First Lapwings appeared in late May – early June, and the numbers steadily increased to reach a peak in mid-late August (only in 2012 at the beginning of October, and in 2014 in mid-July) and slowly declined from September to October. Last birds were observed in early December. Eurasian Curlews started migration in late June and were present until December. Timing of peak numbers varied widely between years. These species wintered very rare: max. 700 Eurasian Golden Plovers, single Northern Lapwings and max. 280 Eurasian Curlew. There was a clear positive relationship between the amount of rainfall in June–October and the maximal numbers of Eurasian Golden Plovers and Northern Lapwings in a given year. Due to the exceptional importance of the IBA for migrant waders, it is necessary to reduce human pressure and to ensure protection of the sandy islands in the river bed.
Keywords: Eurasian Curlew Numenius arquata, Eurasian Golden Plover Pluvialis apricaria, IBA Lower Vistula River Valley, migration dynamics, Northern Lapwing Vanellus vanellus
