Reliability of the mapping method for censusing Blue Tits Parus caeruleus

Abstract

The bird assemblage of the 30-ha mature oak forest in Moscow was censused by the mapping method during the period from 1 April to 30 June 1993 . Special attention was paid to obtaining simultaneous records of singing birds. In a 12 .2-ha part of the forest, the actual number and distribution of territories of the Blue Tit was studied by mapping the positions of individually marked birds and nest-searching . The total number of territories evaluated in the 12.2-ha study plot, on the basis of mapping censuses, was 22. The actual number of territories was the same (22-22 .5) . Six "paper territories" coincided fairly well with the respective actual territories . For seven more "paper territories", it was possible to find counterparts among the actual territories . One actual territory covered the two "paper territories", and one of the "paper territories" seemed to combine the two actual ones . Registering the calling birds seemed to provide useful additional information for evaluating the species map. There was no evidence that female singing interfered with the census work.