The song of the chaffinch Fringilla coelebs is one of the best studied song patterns of any bird species. The geographic variation of song structure has received special attention and was investigated in detail in several parts of western Europe, especially England, Scotland and Germany. As far as we know, a thorough large-scale sonagraphic analysis of geographic variation in central and eastern Europe is still missing. Here we report aspects of song type distribution, of repertoire sizes, and of the occurrence of the widespread terminal song element kit in several chaffinch populations in Poland. During the breeding season 1994 we recorded 84 male chaffinches in five areas (average distance between areas: 330 km). We found a total of 57 song types, of which up to 21 were sung in the individual study areas. The basic song structure (several trill-like parts followed by a complex end phrase), duration and the overall distribution of song types (song type sharing between areas) matched those described for western Europe, but there were differences in the frequency distribution of song types within a population and to some extent in repertoire sizes. Specific results:
1) There was a negative correlation between the number of song types shared and the distance between two areas.
2) In each of the study areas, some song types were more frequent than others. However, even the most common song type within any study site was sung by not more than 20 to 33% of all males of that area, the lowest values reported so far for chaffinches. Such an unusual frequency distribution of song types may be due to factors like pronounced changes in song structure during song learning and/or a high exchange rate (immigration and emigration) of males with other areas. This, however, still needs to be investigated.
3) Males had a mean repertoire of 2.0 song types, which is significantly smaller than most of the repertoires reported for England, Scotland and Germany. There was a pronounced similarity between the study areas in the mean repertoire size of males (an average of 2.0 song types per male
in four areas and 1.9 song types in the fifth area).
4) The characteristic terminal song element kit was sung in all study areas. However, the proportion of males with kit differed significantly between the sites (8 to 100%), with highest values in the northwestern populations.
We plan to investigate the songs of chaffinch populations in central and eastern Poland to determine whether there is a geographic gradient in the kit frequency (from north to south?) or whether it varies in an irregular pattern.