| Abstract: | The hypothesis is suggested that resource depression is one important factor behind the observed regular nest spacing of many birds of prey. It predicts that the proportion of evasive prey in the predator's diet should be reflected in the degree of regularity in its nest spacing. The idea is tested on data from 24 raptorial bird populations of 19 species. The proportion of supposed evasive prey (birds and large mammals) in the diet was positively correlated with the degree of regularity in spacing of the nests, considering all populations or species. No such significant correlation was found for the six highly territorial species, whereas the correlation was highly significant for the other 13 species. Thus, the hypothesis seems most applicable to species with widely overlapping home ranges. However, resource depression could be one reason for territoriality. |
