Seasonal changes in the timing of hopping and feeding activities of a tropical bird (Estrilda amandava) under natural photoperiod
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The timings of onset and end of hopping and feeding activities of the birdEstrilda amandava, were studied under natural light-dark cycles and they are found to keep pace with the timings of sunrise and sunset. The onsets of hopping and feeding occurred at different timings of twilight and they vary over the seasons. The phase angle difference (ψ) of hopping always shows a considerable phase lead relative to feeding which also varies over the seasons and thus suggests that there may be two endogenous oscillators, one responsible for hopping and the other for feeding.
KeywordsEstrilda amandava hopping feeding photoperiod phase angle difference
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