Great crested grebe podiceps cristatus chick mortality in relation to parental fishing

Abstract

Chick mortality, prey size delivery and parental feeding rate of Great Crested Grebes were studied on ponds differing in fish species, densities and biomass on a fish farm in the south-east of the Netherlands. Chick mortality was highest during the first 2 weeks of life. Our results showed that amongst chicks younger than 3 weeks old, the rate of biomass intake per brood was correlated with the estimated prey abundance. Chick survival was highest amongst broods which received more food per unit time. Prey size increased as the young grew older, but older chicks still received very small items. On Carp ponds, parents delivered more prey per unit time to small young than on RoachlRudd ponds, but the rate of fish biomass delivery did not vary among pond types. This is because on average fish caught at Carp ponds were smaller than at RoachlRudd ponds. Presumably parental fishing opportunities in combination with prevailing weather conditions determine partial brood loss in Great Crested Grebe chicks. © 1994 Taylor & Francis Group, LLC.