Diurnal time-activity budget and foraging techniques of red-crested pochards (Netta rufina) wintering at the wetlands of West Bengal, India

Authors: ARKAJYOTI MUKHERJEE, SUDIN PAL, SUBHRA KUMAR MUKHOPADHYAY

Abstract: The present study aimed at recording the time-activity budget and feeding techniques of red-crested pochards (RCPs) to test the hypotheses that feeding techniques were influenced by the sexes and contrasting physical conditions of the habitat. The timeactivity budget was quantified using the scanned sample approach. In this study, the mean sex ratio of the RCPs was recorded as 0.655. Dominant behavior was sleeping or resting (42.8% in February to 47.0% in January), followed by swimming (27.1% in February to 29.8% in December), feeding (10.9% in December to 16.6% in February), and preening (9.0% in January to 12.1% in February). During the diurnal hours, resting was highest in the morning, while swimming and feeding were both highest midday. Climatic factors, such as the maximum and minimum air temperatures, maximum and minimum air temperature differences, and day length, were considered to be influential on the diurnal time activities of the RCPs. Male birds were more frequent divers than the females and the duration of diving was greater in males than in females. However, in shallow water, beak dipping and upending were major foraging techniques in both sexes. The depth of the water played a significant role in the selection of the feeding techniques.

Keywords: Red-crested pochard, diurnal behavior, foraging technique, migratory waterbird, time-activity budget, wintering

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