A dammed storage reservoir on the Narew river, with a maximum area of 3,300 ha. To the north the site extends to Kozieg³owy village, and includes the mouth of the Bug river. The northern and western shores are high and steep, but along the southern and eastern sides the reservoir is separated by river embankments from extensive cultivated meadows, which cover the former flood terrace. Important bird habitats here include oxbow lakes, islands and willow Salix bushes. The reservoir is used for recreation, and there are summer houses.
An important site for migrating waterbirds in autumn (c.20,000 in total, mainly ducks, swans, Fulica atra and gulls Larus) and also for wintering wildfowl (total 6,800). Breeding species of global conservation concern that do not meet IBA criteria: Crex crex (12 pairs).
BirdLife International (2020) Important Bird Areas factsheet: Zegrzynski reservoir. Downloaded from http://www.birdlife.org on 04/07/2020.