engleski

Numbers and seasonal activity of Anatidae at Draganić fishponds in NW Croatia

We studied all species of Anatidae at Draganići fishponds (NW Croatia) from August 1991 to January 1995 during the breeding, wintering and migration periods. Twenty species were noted, of which 13 occurred regularly, the other 7 were irregular or rare visitors. Breeding was recorded for eight species. The most numerous breeders were Mallard Anas platyrhynchos and Pochard Aythya ferina. The population of relatively numerous Ferruginous Duck Aythya nyroca is especially important because our results show that its population in Croatia was previously underestimated. The stable (or even increasing) Croatia population of Ferruginous Duck obviously had a high importance for this globally threatened species (ch. Tucker & Heath 1994).In the three breeding Aythya species the fledging begins about 10 to 20 days later (depending on the species) than in central Europe (cf. Cramp & Simmons 1977). Total numbers of duck during peaks in August and October were the highest in 1991, when the war activities were close to the fishponds ; in later years number decreased continuously. Again Mallard was the most numerous species, the variation in the total was mainly due to Mallard dynamics.

Anatidae; duck numbers; breeding density; seasonal occurrence; fish ponds

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