Territoriality and breeding biology of the coot (fulica atra (l)) at Attenborough

Abstract

Field work was carried out from August 1972 until August 1974 on an area of 119 ha. Of the Attenborough Gravel Pits in Nottinghamshire. A total of 135 territorial pairs were monitored with reference to size of territory, length of laying season, clutch size, egg size, hatching and fledging success and relationship with other waterfowl. Territory size varied from 0.08 ha. To 1.37 ha. with a mean of 0.46 ha. It was not correlated with clutch size or bredding success. Both members of a pair defended the territory. A minimum of 19 pairs are believed to have remained on their territories for the whole of the study period. In both years the laying season lasted approximately 2.5 months: peak laying season lasted approximately 2.5 months: peak laying occurring from 24 April to 7 May. It is confirmed that Fulica atra in Europe is normally single brooded. No correlation was found between egg size and clutch size. In both years egg laid early in the breeding season were found to be significantly larger than all other eggs. The incubation period was 23/24 days. The mean clutch size of the 124 completed clutches was 6.1 ± 0. 14 eggs. In Britain as a whole the overall mean clutch size was calculated to be 6.0 ± 0.08 eggs which is significantly smaller (d = 23.006, P<0.001) than the mean clutch size (7.9 ± 0.03) of the coot in continental Europe. A hatching rate of 49.3% was recorded and of those chicks that hatched 41.0% fledged at approximately eight weeks. Breeding success averaged 20.2% with a mean of 1.3 young fledged per breeding pair. Both parents build the nest, incubate the eggs and feed and care for the young. Some young were still on territory, with their parents, at Il| weeks of age. Intraspecific aggression was noted throughout the year, but interspecific aggression, apart from that towards the moorhen, only occurred in the breeding season. It is concluded that interspecific aggression is unlikely to harm other waterfowl in the area.