Bird abundance as an indicator of habitat quality for breeding birds

Reproductive success and survival of birds often are impractical to measure. Therefore, biologists frequently rely on measures of bird abundance alone to evaluate habitat quality for breeding birds. I examined whether results from standard survey techniques for birds during the breeding season reflected number of nesting pairs and reproductive success of 5 passerine species. Abundance of 3 species was positively associated with number of nesting pairs, but the relationship between abundance and reproductive success varied among these species. Differences in detectability of breeding males may partly explain why abundance and number of nesting pairs were related in some species and not in others. Variations in the availability and quality of habitat patches among plots could produce the different relationships I observed between abundance and reproductive success. My results suggest that measures of reproductive success as well as abundance should be used to determine habitat quality for breeding birds