Effect of desert climate on singing behaviour of bulbuls
Nail Hasan, Motasim Badri
We studied the effect of ambient temperature on the start of singing for white-cheeked bulbuls (Pycnonotus leucotis) all year round in a quiet site in a desert environment. Bulbuls started dawn chorus almost unusually early towards the end of January which is marked by increasing ambient temperatures and photoperiod and also coincides with the beginning of the breeding season. They continued early singing until July which is marked by decreasing photoperiod regardless of minor temperature fluctuations. This is the first study that shows evidence that daily start of singing is directly and significantly influenced by day to day fluctuations in temperature. It is concluded that early singing is initiated by increasing temperatures and is susceptible to daily fluctuations and that these birds must have evolved to start their daily activities by singing early and foraging before temperature becomes very hot upon sunrise.