The distribution of breeding merlins Falco columbarius in relation to food and nest sites

Abstract

Merlins preferred hooded crow Corvus corone cornix nests less than two years old, which had not been used previously by merlins. Artificial nests meeting these requirements were provided in a study area where the number of suitable nests for merlins was low. Food abundance (number of passerines) was estimated in this area and in a control area where up to 15 merlin pairs could breed. The number of breeding merlin pairs did not increase in the nest provision area in relation to the number of nests provided. One possible reason was that the accessibility of prey was limited by snow. Therefore, it is suggested that the density of breeding merlins in this area was mainly determined by food particularly during the mating period. -from Authors