EXTENDED FLIGHT-SONGS OF VESPER-SPARROWS

While conducting fieldwork on the breeding ecology of grassland birds at Kennebunk, Maine, we documented the existence of extended flight-so ngs of Vesper Sparrows (Pooecetes gramineus). In general, we observed this behavior very infrequently, usually less than three times per bre eding season. Extended flight-songs were about three times as long as primary songs and contained elements not typically found in primary so ngs. Extended flight-songs occurred more frequently late in the breedi ng season. Within the subfamily Emberizinae, extended flight-songs hav e now been documented for at least 10 species but their behavioral fun ction remains unclear.