Some aspects of the breeding biology and vocalizations of the fox sparrow (Passerella iliaca Merrem) in Newfoundland

Abstract

The breeding biology and vocalizations of the Fox Sparrow (Passerella iliaca Merrem) was studied during the 1977 and 1978 breeding season in Newfoundland. -- The early spring migration, territory establishment, and nesting activities are discussed. Analysis of nest record cards indicated nest height was significantly correlated (r = -.600) with advance of the breeding season. Incubation and nestling periods were found to be just over 12 days and 9 days respectively. Nestling growth was rapid, k = 0.566, and the relative growth of body parts showed a differential in favour of early development of legs and feet. -- Nestling call notes, adult call notes, and presumed female song are described and discussed. The male primary song is described and variation analyzed. The repertoire size of 96.4% of the birds recorded was one song, and only 3.6% sang two songs. Song structure was constant through the breeding season. Analysis of variance of basic song parameters showed some variation between localities but no trends were detected. Cluster analysis showed substantial sharing of syllables within a locality but differences were only apparent in sample that were separated by long distances in continuous breeding habitat or a geographic barrier. The last six syllables of the song were shown to be most closely associated with locality. Song correspond to geographical variation rather than a system of dialects. Preliminary evidence suggests that Fox Sparrows do not discriminate between songs of their own and other, even very distant, localities.