VOCALIZATIONS OF THE TREE SWALLOW (TACHYCINETA-BICOLOR) DURING THE PRELAYING PERIOD - A STRUCTURAL AND CONTEXTUAL ANALYSIS

We studied the vocalizations of adult tree swallows (Tachycineta bicol or) in eastern Ontario during the prelaying period. We distinguished a nd named five call types and one song type using structural criteria, and quantified the percent occurrence of each vocalization type in var ious behavioral contexts. Males and females share the same vocalizatio n types, although males give the ticking call and song more often than females. Analysis of five parameters of vocalization structure showed no evidence of sexual dimorphism. Temporal parameters were usually st ereotyped among individuals, whereas frequency parameters often varied among individuals and, therefore, might function in individual recogn ition.