Effect of Ambient Temperature on Dawn Chorus of House Sparrows

Abstract

House sparrows (Passer domesticus) are omnipresent. Their study in different environments can shed light on effects of environment on bird behaviour. Therefore, the start of singing of house sparrows was studied all year round in a university housing compound with almost zero traffic noise in an arid dry desert climate. Sparrows start dawn chorus unusually early towards the end of January which is marked by increasing ambient temperatures and photoperiod and also coincides with the breeding season. Evidence that daily start of singing is directly and significantly influenced by major daily fluctuations in temperature during January and February is shown. Birds continue with early singing from March until July regardless of minor temperature fluctuations. Sparrows revert to late singing towards end of July. July is marked by the beginning of decreasing photoperiod but has no substantial fluctuations in temperature. The effect of climate on start of singing is discussed. This investigation is only concerned and concentrates on the shifting from normal start of singing to very early singing in spring season. It is concluded that early singing is initiated by increasing temperatures and is susceptible to daily fluctuations only early in the season and that these birds must have evolved to start their daily activities by singing early and foraging before temperature becomes very hot upon sunrise.