The effect on the woodpigeon ( Columba palumbus) of the introduction of oilseed rape into Britain

Abstract

The production of oilseed rape on a large scale in Britain began in 1973 and the woodpigeon ( Columba palumbus) quickly became a major pest of this crop. This paper uses ringing recovery data to examine the effects of the introduction of oilseed rape upon the movements and survival of the woodpigeon, and observational data to investigate changes in foraging behaviour. The mean distance travelled between ringing and recovery sites decreased in areas of high oilseed production but increased where little oilseed rape was grown. In good arable areas, the introduction of oilseed rape did not affect woodpigeon survival but it increased woodpigeon mortality in poor arable areas, probably as a result of increased shooting pressure. Oilseed rape is the preferred winter food of woodpigeons and they forage more efficiently on oilseed rape fields than pastures, the main alternative source of food in winter. After the widespread cultivation of oilseed rape, the average weight loss in a woodpigeon over the winter months became significantly less. Following the introduction of oilseed rape into Britain, overwinter mortality from starvation declined and the number of young produced each summer now has a more important effect upon woodpigeon population size.