Distribution, movements, and survival of the critically endangered Bengal Florican Houbaropsis bengalensis in India and Nepal

Abstract

We undertook field surveys of the critically endangered Bengal Florican throughout its range in India and Nepal and used the results to develop models of distribution to identify new populations. We also tagged 11 birds with satellite transmitters to assess their distribution and habitat use during the non-breeding season, about which nothing is known. The models suggest that the distribution is now extremely fragmented in the west, although potentially sizeable populations may await discovery in eastern parts of the species’ range, particularly along the Brahmaputra River. After breeding, tagged birds left their breeding sites inside protected areas (PAs) and moved up to 80 km into landscapes characterised by relatively low-intensity agriculture along rivers with lower than average human population densities. Many birds spent more than six months away from their breeding grounds outside PAs. Models of non-breeding distribution suggest that some breeding areas become unsuitable at that time of the year, and therefore that birds may be forced to leave PAs at that time. Tagged birds had high annual adult survival rates (0.92, 95% confidence interval 0.858–0.953). Home ranges during the non-breeding season were significantly larger than breeding season home ranges. The results suggest that the conservation of this species needs to account for the species’ use outside the breeding season of less intensively cultivated floodplain-agricultural landscapes, as well as protecting breeding grassland sites.