Notes on Food Habits of the Black and White Owl

Abstract

The Black and White Owl, Ciccaba nigrolineata, is a neotropical wood owl whose feeding habits are little known, as is the case for most tropical owls (Clark et al. 1978). We collected the pellets produced by a pair of Black and White Owls from September 17-October 25, 1981 in Mesa de Cavacas (95'N, 6948'W), a town six kilometers west of Guanare, Portuguesa state, Venezuela. This site is located at 300 m on the Andean piedmont, the transition zone between the Andes Cordillera and the plains (llanos), of the dry tropical forest life zone (Ewel et al. 1976). The natural vegetation has been mostly replaced by crops and pastures. We gathered pellets in a rural town made up of onestory houses surrounded by small fruit orchards, mainly mango (Mangifera indica), guava (Psidium guayaba), plantain banana (Musa paradisiaca), and papaya (Carica papaya). During this period the owls regularly roosted during the day in a large mango. We were not able to count the number of pellets, or the number of prey per pellet because some had disintegrated. We totaled the number of individuals eaten according to each taxon, generally the species, on the basis of the largest number of parts used for identification (crania, mandibles, beaks, feet, elytra, etc.). For bats and birds, the body mass assigned to each prey was based on comparative material collected in the study area. For insects and amphibians, we determined mass using regression equations for total length and body mass calculated by Zug and Zug (1979) and C. Ramo and B. Busto (unpubl. data), respectively. We identified a total of 64 prey (38 vertebrates and 26 insects) (Table 1). The most frequent prey were mammals (45.3% of the total), including two commensal rodents and 27 bats belonging to 14 species and 5 feeding guilds (Bonaccorso 1979). Birds represented 9.4% of the total. Considering biomass, the importance of insects greatly diminishes (3.7%) and the importance of vertebrates except amphibians increases (Table 1). The size of the vertebrates ranged from 10 to 150 g; most (68.6%) were between 20 and 60 g. The insects were mainly tettigonids and scarabs longer than 30