LONG-TERM CHANGES IN THE BREEDING BIOLOGY OF THE WOODPIGEON COLUMBA-PALUMBUS IN EASTERN ENGLAND

Changes in agricultural practice in eastern England have been shown to have had marked effects upon the winter population size of the woodpi geon Columba palumbus. This study examines whether changes in the bree ding success of the woodpigeon have also occurred. Data were gathered between 1962 and 1983 on the breeding activities of woodpigeons within a wood near Newmarket in eastern England. The number of nests monitor ed each year varied between 16 and 122 with a mean of 45. Agricultural changes resulted in a steep decline in the winter population size in the late 1960's and the breeding population showed a similar fall. Bef ore this decline, productivity was on average 2.8 young per pair, but afterwards it was only 1.8 young per pair. This drop in productivity r esulted from greater egg predation; which increased steadily over the study period. Increased egg predation and variation in seasonal patter ns of breeding behaviour are discussed in relation to likely predator numbers and changes in both agricultural and shooting practices. In th e 1960's, overwinter starvation was the major limiting factor on the w oodpigeon population, but after the mid-1970's low productivity has in creasingly become the most important factor.