I observed Ashy-faced and Barn owls capture bats in flight, but only at sinkholes and cave entrances, where bats exited or entered their retreats in large numbers. Therefore, it is remarkable that so many diurnal species were captured by both Tyto species. Diet data have been widely reported for Barn Owls through much of their cosmopolitan range, although most reports are for continental populations (see compilation by Taylor 1994). Rodents composed 48.6% and 91.5%, whereas bats formed 18.8% and 2.6%, respectively, of the total number of prey (Wetmore and Swales 1931). The second most frequent prey class for both owl species was birds, making up 28.8% of the material examined for Ashy-faced Owls, and 12.3% for Barn Owls (U = 8037.5, P < 0.001; Table 2). Although the IUCN/Birdlife ranks this species as “least concern” no accurate population data exists. The presence of remains of bats that do not live in caves (e.g., tree-foliage-roosting Cuban fig-eating bat [Phyllops falcatus]), however, raises other questions of availability and capture techniques used by the owls. Body masses of a few species of smaller frogs and lizards for which I could find no mass data were estimated by weighing similar-sized species. The proportion of reptiles and amphibians (11.1%) in Barn Owl samples from Hispaniola was slightly greater than the extremes reported (0.8–7.4%; Buden 1974, Arredondo Antúnez and Chirino Flores 2002) in the region. I found no differences among prey proportions in materials collected among the habitats for the Ashy-faced Owl (χ2 = 2.90, df = 9, P > 0.05) or those for the Barn Owl (χ2 = 3.704, df = 6, P > 0.05); i.e., there were consistent relative proportions of mammals, birds, amphibians, and reptiles within each owl species' prey. 2001], and 3.8% in Cuba [Arredondo Antúnez and Chirino Flores 2002]). 2006). 2002). Bird masses in Ashy-faced Owl prey samples ranged from 4 to 1150 g, and 4 to 300 g in Hispaniolan Barn Owl samples. The Ashy-faced Owl is locally common in dry and moist scrub forest and woodland from sea level to 2000 m (American Ornithologists' Union 1998, Keith et al. Prey remains and pellets were collected from two habitats (dry scrub/coastal woodland and montane broadleaf evergreen forest) shared by Ashy-faced and Barn owls. Regurgitated pellets and uneaten prey at nests and roosts provide an accurate representation of the diet of owls (Marti et al. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Ashy-faced Owl prey materials contained 125 vertebrate species, whereas Barn Owl materials included 114 species, with 92 species in common between the two owls. This content is available for download via your institution's subscription. I collected food materials at active nests and roosts of owls in the Dominican Republic incidentally and at irregular intervals from December 1975 through December 2004 (Table 1). Mandibles, skulls, and femurs of mammals; bones and feathers of birds; bones and skin of reptiles and amphibians; and invertebrate parts were separated and identified. In the Hispaniolan populations, these characteristics were true of both species, but particularly the Barn Owl. Indices for the diversity of the owls' prey revealed that the diet of the Ashy-faced Owl was more diverse than that of the Barn Owl: i.e., H′Ashy-faced Owl = 3.044 and H′Barn Owl = 2.214; P < 0.05. A total of 8322 vertebrate prey individuals could be identified at least to genus from materials collected at nests and roosts: 4495 for Ashy-faced Owls and 3827 for Barn Owls (Table 2). Size of the two owl species' prey ranged from 0.6 g (tuck-wheep frog [Eleutherodactylus abbottii]) to 1200 g (blunt-headed green treesnake [Uromacer catesbyi]) in Ashy-faced Owl, and 0.6 g (tuck-wheep frog) to 650 g (Hispaniolan desert boa [Epicrates fordii]) in Barn Owl. In contrast, more species of nonpasserines (n = 29) than passerines (23) were recorded for Barn Owls, although its diet consisted of more individuals of passerines (349) than nonpasserines (203). Wetmore and Swales' (1931) report of 18.8% bats at one of their sites, and my tally of 11.1% bats for Ashy-faced Owl, are similar to the proportion of bats in Barn Owl prey in Hispaniola (12.2%; present study), but higher than the proportion of bats among Barn Owl prey reported elsewhere in the Caribbean Islands (1.7–2.0%; Buden 1974, Arredondo Antúnez and Chirino Flores 2002). To access this item, please sign in to your personal account. The late Albert Schwartz helped with species identification and confirmation for several reptiles and amphibians. Prey of Ashy-faced Owl (Tyto glaucops), as published in Wetmore and Swales (1931). Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website. A total of nine species of amphibians was found among the Ashy-faced Owl material, and 11 species among that for Barn Owl. Arturo Kirkconnell kindly provided the Spanish resumen. Bond (1977) suggested that Barn Owls capture more land birds in the Antilles and Bahamas than all other native predators combined. Birds made up a greater proportion of Ashy-faced Owl prey (28.8% frequency, 14.8% mass) than of Barn Owl prey (12.3% frequency, 5.1% mass). The Ashy-faced Owl (Tyto glaucops) is endemic to Hispaniola, where the Barn Owl (T. alba) became established after ca. It will be interesting to study the development of coexistence between the two Tyto species in Hispaniola to determine if further niche separation develops. No reptiles or amphibians were found among the Ashy-faced Owl prey remains for one site reported by Wetmore and Swales (1931), whereas amphibians and reptiles formed 9.3% of the prey at the second of the two sites where remains were quantified (Wetmore and Swales 1931). This content is available for download via your institution's subscription. In their samples, passerines were equal to nonpasserines in representative species (15 each), but the former comprised 68% of bird prey individuals; these proportions are similar to those I found for Ashy-faced Owl. José A. Ottenwalder and Simón Guerrera provided facilities at Zoodom in Santo Domingo. A clutch of between three and seven eggs is laid some time between January and July. Materials collected at two of four localities in Haiti and the Dominican Republic were characterized qualitatively for Rattus spp. Similarly, Simpson's index showed the prey species of Ashy-faced Owl to be more diverse than those in the diet of Barn Owl: DAshy-faced Owl = 6.316 and DBarn Owl = 2.933 (P < 0.05). 6–9 g, Wetmore and Swales 1931) and Barn Owls in the Antilles and Bahamas (ca. Numbers of individuals (frequency) and biomass of prey of Ashy-faced Owl (Tyto glaucops) and Barn Owl (T. alba) as determined from regurgitated pellets and food remains collected at nests and roosts at 12 localities, Dominican Republic, 1975–2004. The same frequency pattern was true for reptiles, with Ashy-faced Owl material composed of more reptiles (7.7%) than found in Barn Owl material (6.5%; U = 837.5, P < 0.01). 2003, Latta et al. Size of the two owl species' prey ranged from 0.6 g (tuck-wheep frog [Eleutherodactylus abbottii]) to 1200 g (blunt-headed green treesnake [Uromacer catesbyi]) in Ashy-faced Owl, and 0.6 g (tuck-wheep frog) to 650 g (Hispaniolan desert boa [Epicrates fordii]) in Barn Owl. The Ashy-faced Owl had a more diverse prey base (H′ = 3.04, D = 6.32, J = 0.610) than did the Barn Owl (H′ = 2.21, D = 2.93, J = 0.444). What Do Ashy-faced Owls Eat.