Stygian owl

Abstract: This paper tested the hypothesis that the structural components of vegetation have impact over the distribution of owl species in a fragment of a semi-deciduous seasonal forest. This paper also determined which vegetation variables contributed to the spatial distribution of owl species. It was developed in the Perobas Biological Reserve (PBR) between September and December 2011. To conduct the owl census, a playback technique was applied at hearing points distributed to cover different vegetation types in the study area. A total of 56 individual owls of six species were recorded: Tropical Screech-Owl (Megascops choliba), Black-capped Screech-Owl (Megascops atricapilla), Tawny-browed Owl (Pulsatrix koeniswaldiana), Ferruginous Pygmy-Owl (Glaucidium brasilianum), Mottled Owl (Strix virgata) and Stygian Owl (Asio stygius). The results suggest that the variables of vegetation structure have impact on the occurrence of owls. The canopy height, the presence of hollow trees, fallen trees and glades are the most important structural components influencing owl distribution in the sampled area.

Abstract: Hispaniola is the second largest island in the Caribbean that includes the countries of Dominican Republic and Haiti and has five resident owl species inhabiting open landscapes, rainforests, human-modified areas, and cities. The five species are the barn owl (Tyto alba), the endemic ashy-faced owl (T. glaucops), burrowing owl (Athene cunicularia), stygian owl (Asio stygius), and short-eared owl (A. flammeus). The stygian owl is the most threatened and least known of the five species. Puerto Rico represents the smallest and easternmost of the Greater Antilles, and it has a total of three species of owls inhabiting forest, open landscapes, and human-modified areas. The status of the barn owl on the island is not well known as the first breeding pair was documented in 2015, the short-eared owl is mostly restricted to lowlands and low montane open areas, and the Puerto Rican screech owl (Megascops nudipes) is the most common and widespread owl on the island. The Virgin Island race of the Puerto Rican screech owl (M. nudipes newtoni) that formerly inhabited a forested area of the Virgin Islands and Puerto Rico’s satellite island of Vieques is apparently extinct. These owls are suffering from changing landscapes and loss of natural habitat, especially in Haiti where natural resources and forests are nearly gone. Natural habitat remaining on Hispaniola is mainly confined to protected areas and the majority lack enforcement and protection. On the other hand, in Puerto Rico, the abandonment of forested areas such as shade coffee plantations, mainly in the highlands, has resulted in forest regeneration benefitting the Puerto Rican screech owl, and the abandonment of sugar cane plantations in the lowlands has favored the local subspecies of short-eared owl and most likely the colonization by barn owls.