Sobre la nidificación de Podiceps cristatus (Linn.) (Aves, Podicipedidae) en el NE de España

Abstract

The areas of Catalonia in which Podiceps cristatus breeds nowadays are listed, giving special attention to the Delta del Ebro. The reproductive population of this area, increased during the seventies, which in 1979 was estimated to be of 80-95 pairs. The results are based on the census carried out during the spring of 1979, which methodology is described. Breeding territories were occupied in March, and most chicks were born between the end of June and July. In a sampk of 33 hatches the mean number of chicks was of 1.7. The reproductive habitat of the Delta del Ebro is the reedbeds with only one species of reed-grass Phragmites australis, slack, of nearly constant 20-25 cm deepress and without much water current. In the Delta del Ebro, breeding has not been recorded in areas of Typha angustifolis.