RELIABILITY OF THE MAPPING METHOD FOR CENSUSING BLUE TITS PARUS-CAERULEUS

The bird assemblage of the 30-ha mature oak forest in Moscow was censu sed by the mapping method during the period from 1 April to 30 June 19 93. Special attention was paid to obtaining simultaneous records of si nging birds. In a 12.2-ha part of the forest, the actual number and di stribution of territories of the Blue Tit was studied by mapping the p ositions of individually marked birds and nest-searching. The total nu mber 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 t he respective actual territories. For seven more ''paper territories'' , it was possible to find counterparts among the actual territories. O ne actual territory covered the two ''paper territories'', and one of the ''paper territories'' seemed to combine the two actual ones. Regis tering the calling birds seemed to provide useful additional informati on for evaluating the species map. There was no evidence that female s igning interfered with the census work.