Does the common kingfisher (Alcedo atthis) select the most energetic fish prey?

Abstract

During the check-rearing period, strategies of prey provisioning can have a decisive impact on several reproductive aspects. Adults can maximise their foraging effort by increasing the number of fish-prey brought to the nest per unit time and/or by catching more energetic prey, i.e. larger prey or prey with relatively higher caloric values. The Common Kingfisher (Alcedo atthis) is a fish-eating predator normally breeding in freshwater habitats. We collect data on fish-prey proportions found at nests (n=10) and determined the caloric content of such fish-prey (6 species overall) in rivers in northen Iberia. The proportion of each fish-prey species in the nest was not correlated with the proportion of lipids, proteins or carbihydrates, nor with its caloric content. Furthermore, the most energetic prey was nor the most coomonly consumed, illustrating the fact that the Common Kingfisher does not fish for the most energetic prey during the chick-rearing period.