Impact of Common Kingfisher on a salmon population during the nestling period in southern England

Abstract

The effect of fish-eating birds on their fish-prey populations has been a matter of concern to conservationists, anglers and fishery interests, especially when both bird and fish species have conservation status and are afforded some protection by law. Understanding the predator-prey interactions will assist in managing these potential conflicts. This situation could arise with the Common Kingfisher (Alcedo atthis), whose range covers many important Atlantic salmon (Salmo salar) rivers. In order to increase our knowledge on predator-prey interactions between these species, we collected data on the diet and feeding rates of a kingfisher population breeding in an Atlantic salmon river in southern England (River Frome). Results showed that, during nestling period, kingfishers provided a mean of 62 fish per day to the nest and that the mean salmon intake was 2.5% of the entire diet, which is equivalent to 86 salmon parr consumed by each kingfisher pair for the entire breeding period (assuming 2.2 broods/pair/year). The total 0-group salmon population in the River Frome was 63,900. The estimated loss of 0-group salmon parr to the kingfishers over one season was 0.8%, thus supporting the view that the kingfisher has a negligible biological impact over this salmon population.