Does the Common Kingfisher (Alcedo atthis) select the most energetic fish prey?

Abstract

During the chick-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 collected 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 northern Iberia. The proportion of each fish-prey species in the nest was not correlated with the proportion of lipids, proteins or carbohydrates, nor with its caloric content.