Singing Behavior, Song Types on Their Wintering Grounds and the Question of Leap-Frog Migration in Puget Sound White-Crowned Sparrows

Singing behavior in Zonotrichia leucophrys pugetensis on their wintering grounds in California was studied. Additionally syllables from songs of overwintering birds were compared to syllables in songs recorded previously on their breeding grounds in an effort to identify wintering grounds of dialectal populations. Much singing was recorded from recently arrived birds in the fall. At least some spontaneous singing was recorded every month of the year. However, singing decreased in December and increased in February, probably in response to increasing day lengths. Song development was complete or almost so in some juveniles recorded upon arrival in California. At least some birds responded to playback with singing during all months on the wintering grounds, however, responses peaked during arrival in the fall and before departure for the breeding grounds in the spring. At each wintering locality, several dialects were sung, indicating that more northerly breeding populations do not leap-frog and winter south of more southerly breeding populations. The resident Z. l. nuttalli sometimes borrow elements from wintering Z. l. pugetensis to construct "hybrid" themes. However, syllables from alien dialects are soon lost from the population due to match-countersinging by Z. l. nuttalli males.