Applying a territory mapping method to census the breeding bird community composition in a montane forest of Taiwan.

Abstract

Territory mapping is considered one of the most accurate methods for estimating forest bird densities and studying the subtle relationships between birds and their habitats. Nevertheless, the territory mapping method has rarely been applied to estimate entire bird communities in tropical and subtropical regions of Asia. We conducted territory mappings in an area of around 40 ha at a mid-elevation site in Taiwan for a period of 20 consecutive weeks (40 census days in total) from early March to late July 2005 to establish field protocols of territory mapping and examine the effectiveness of this method in detecting the avian community composition. Fifty-seven bird species from 5719 registrations were recorded during the 40 field censuses. The results suggested that the optimal period for territory mapping at the study site was during 10~12 wk from early April to late June, because during this period, the prevalences of most breeding species were highest. Within this period of time, we registered 88% of the breeding species recorded historically. Repeatedly playing 2 repetitions of the territorial songs of the 14 commonest species did not significantly affect the total number of breeding species or registrations recorded on each census. These results indicate that with a good trail system, the territory mapping method is suitable for censusing bird communities in forests of Taiwan and similar habitats in Asia. However, due to the non-territorial behavior, asynchronous breeding season, and multiple broodings of birds in tropical and subtropical regions, the efficiency of territory mapping method is not as good as that in temperate regions.