Singing the night away: Diel and seasonal patterns of LeConte’s sparrow primary and flight songs

Abstract: Bird songs are typically associated with mate attraction and territorial defense behaviours. Some passerine birds sing two categories of songs, primary and flight songs, that vary in song rate and complexity and may vary in function. LeConte’s sparrow (Ammospiza leconteii) is one of the least studied North American passerines; despite several descriptions of flight songs, the vocal behaviour is poorly described. We used a passive acoustic monitoring dataset (PAM) from northwestern Ontario, Canada, to describe the structure of LeConte’s sparrow flight songs and to determine whether song type use varied with time of day and/or season We identified songs that included extra elements in addition to the primary song that match the description of a flight song. The flight song was less likely to be sung than primary song at all periods of the day. The probability of singing and amount of both primary and flight songs varied significantly with period of day and calendar date with the two song types showing different seasonal patterns among diel periods. We found no clear temporal partitioning of types, although the diel period in which each songs’ activity peaked differed. We found flight songs were most frequent in the evening or early dusk chorus. After evening civil twilight, LeConte’s sparrows did sing at late dusk and at night suggesting they are regular nocturnal singers, particularly early in the breeding season. The probability of singing in the morning declined with date and song rates and probability of singing were higher at dawn than after sunrise. Thus, surveys targeting LeConte’s Sparrow should be conducted early morning, beginning before sunrise and in June to confirm presence. We hope that future PAM recording paired with focal recording of individuals can be used to examine variation in the structure of flight songs within and among individuals and populations.