Mirrored sequences of colonisation and abandonment by pairs of Golden Eagles Aquila chrysaetos

Abstract

We report colonisation by extra breeding pairs of Golden Eagles, and subsequent abandonments, in part of northeast Scotland during 1895-1985. Thenumber of pairs rose from three in 1895-1937 to eight by 1948, and then fell to four during 1959-71 in reverse of the colonisation sequence. This fits the concept of hierarchic quality of habitat used, or of bird quality. Possible mechanisms to explain this are discussed.