Natural and artificial population control in the wood‐pigeon. The third Barnes Memorial Lecture

The Relationships Between Wood-Pigeons and Their Clover Food Supply and the Mechanism of Population Control

“…Although any reductions in clover availability that result from the wood-pigeon's feeding behaviour are transient and the plants recover uninfluenced by defoliation, the woodpigeon population suffers for a much longer period. Murton et al (1964a), supplemented by Murton (1965a), have shown that the minimum size of the winter wood-pigeon population in the study area was determined by the lowest level to which the clover stocks decreased.…”

“…8 shows that when the birds were all forced to feed on Brassicae many more suffered; the proportion of under-weight birds was increased and that of the middle-weight class decreased. The age classes in Table 10 should have been sampled in true proportion to their distribution in the population; the subject of differential survival rates between adults and young over the autumn has already been discussed (Murton et al 1964a;Murton 1965a). It can be seen from Table 10 that in February first-year birds had a lower mean weight than adults; it might be presumed therefore that they would be the first individuals to appear in the very low weight classes in adverse conditions and that they 50-1959 1961 1963 u 30- would also suffer a higher mortality.…”

“…Other papers (Murton, Westwood & Isaacson 1964a;Murton 1965a) have discussed the factors regulating population size in the wood-pigeon (Columba palumbus) in a study area in Cambridgeshire. It was shown that, following a post-breeding season population peak, availability of grain on autumn stubbles determined the number of birds surviving in early December.…”