Acta Zoologica Cracoviensia, 32() 1989
Breeding biology of the River Warbler Locustella fluviatilis (Wolf, 1810) in north-eastern Poland
Abstract:
The data presented on the biology of the River Warbler were collected in north-eastern Poland in 1970-1980. The male does not differ from the female either in plumage or in size; the sex of the birds marked was determined on the basis of their behaviour. The breeding territories analysed, 290 in number, lay in wet alderwoods Alnetea glutinosae and forests Querco-Fagetea. Males arrive a few days before females, on the average about 20 May and occupy small territories. Courtship and warning songs, subsong and 9 other calls and voices are described. Forty-two nests, consisting of 4 layers, were found. The River Warbler has one brood a year, which in the case of its destruction may be repeated 3 times. The female lays 3-6 eggs (on the average 4.92). They are incubated by the male and female, whose various behaviours on the nest are described. The incubation period lasts 14-15 days. Young stay in the nest for 12-14 days. They are fed by both adult birds; butterflies, dipterans and arachnids prevail in their diet. Both parental birds attend to the young in the nest (disposal of faeces, brooding, protection against sunshine and rain). The breeding success in the nests studied is rated at 2.79 chicks per pair. The biology of the River Warbler is compared with the data presented for other species of the genus Locustella in literature.
