Distribution, habitat associations and conservation status of the Sri Lanka Frogmouth Batrachostomus moniliger
Authors: Suranjan KARUNARATHNA, Salindra K. DAyANANDA, Dinesh GABADAGE, Madhava BOTEjUE, Majintha MADAWALA, Indika PEABOTUWAGE, Buddhika D. MADURAPPERUMA, Manjula RANAGALAGE, Asanka UDAYAKUMARA and Thilina D. SURASINGHE
Published: Volume 69.1, January 2022. Pages 75-95.
Ecological responses of nocturnal predatory birds to forest cover and other geospatial predictors vary both geographically and taxonomically. Considerable knowledge gaps exist regarding the habitat associations of the Sri Lanka Frogmouth, a nocturnal bird restricted to Sri Lanka and the Indian Western Ghats. Via a 20-year island-wide survey, we searched for frogmouths in Sri Lanka to determine their habitat associations at both local and landscape scales and developed a habitat suitability model (HSM) to predict both current and future distribution. We confirmed frogmouth presence in 18% of the surveyed sites across all major bioclimatic zones (wet, intermediate, dry, and arid) from lower elevations (11-767m), comprising a broad geographic range. Frogmouth presence was mostly limited to forests (90%) with a few sites in agricultural mosaics. Land protection, altitude and both local and landscape-scale forest cover, as well as forest-cover loss at both spatial scales, were strong predictors of frogmouth presence. According to our HSM, the southwestern lowlands and parts of the intermediate zone contained the most suitable areas for frogmouths despite their smaller extent. Although the dry and intermediate zones contained extensive habitats for frogmouth, these regions were relatively less suitable. The habitat associations and geographic range of this species in Sri Lanka differ from that seen in India through negative associations with altitude and absence from montane zones, absence from degraded or severely disturbed habitats and independence from proximity to waterways. The Sri Lanka Frogmouth is sensitive to anthropogenic disturbances, including historical forest losses. We recommend landscape-scale conservation planning that incorporates both primary and mature persistent secondary forests to ensure the protection of this unique iconic species.