We collected data from 10 caves (3 sites) in the North and Middle Andaman Islands to determine the spatiotemporal changes in the roosting pattern of the Andaman populations of Edible-nest Swiftlet (Aerodramus fuciphagus inexpectatus). This echolocating diurnal aerial forager showed temporal variation in its round-the-clock entry and exit patterns. With spatiotemporal variations (site-wise, cave-wise, hourly, and monthly), more than 98% of birds returned daily to the roosting caves between 1700 h and 2000 h. However, their daily departure time (between 0400 h and 0700 h) did not vary spatially (site-wise and cave-wise). The movements of birds at the cave openings were higher during the nestling period in April and May. The daily roosting period inside the caves (mean 525.20 min; SD 82.98) also showed spatiotemporal variation. Day length affected movement of the birds before and after sunset and sunrise. We conclude that roosting movement of the Andaman Edible-nest Swiftlet varied spatiotemporally in the Andaman Islands. This first detailed description of such variation in the roosting patterns of the species will stimulate further exploration of the various biological and environmental factors affecting movements of this cave-dwelling endemic.

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