O. Gy. Dely szerk.: Vertebrata Hungarica 20. (Budapest, 1981)
Demeter, A.: Small mammals and the food of owls (Tyto and Bubo) in Northern Nigeria 127-136. o.
found in Futuk, where only Mastomys was noted in houses. Mastomys cf. erythroleucus (Temminck, 1853) Material: 21 specimens, Wikki (18) and Futuk (9). Specific identity of these specimens is doubtful, as two sympatric species, scarcely distinguishable by gross morphological characters (PETTER, 1977) occur in Nigeria (DOBROZHOTOV et al., 1978). M. erythroleucus and M. huberti are the species designated for West Africa with chromosome numbers of 32 and 38, respectively (PETTER, loc. cit.). Specimens corresponding to PETTER' s (loc. cit.) description of erythroleucus are all fully adult and/or old animals, whereas those with grey belly, flanks and back, reserved for huberti, proved to be subadult or young animals. The sex ratio was 1 o* 1 : 2 o_. Two males had scrotal testes within the period and one female was lactating by 23 July. Two juveniles, aged about 5 days as judged by their weight and head and body length (HUBERT & ADAM, 1975) were collected at Futuk on 6 August. Eleven (48 %) of the specimens were subadults, which suggests that this species was breeding actively in April-June. Gliridae Graphiurus murlnus spurelli Dollman, 1912 x Material: Wikki, 14 August 1978, 1 9. The pregnant female contained three embryos. The specimen was captured on the ground in thick herbaceous cover close to trees and bushes. Table 2. Habitat distribution of small mammals trapped during the rainy season of 1978 in Yankari Game Reserve Habitat Species Fadama ^*P ar * an Savanna Scrub Sandstone Pteleopsis Human Woodland Woodland Savanna Rocks Woodland Habitation Crocidura odora ta Crocidura pasha Tate r a kempi Taterillus gracilis Mus musculoides Acomys cahirinus Myomys daltoni Mastomys erythroleucus Graphiurus murinus Prey of Tyto alba and Bubo africanus Table 3 shows the prey of Barn Owls at Futuk and Wikki. At Futuk shrews and Multimammate Rats were numerically the most important, but M. erythroleucus and Tatera kempi were the major prey by weight. Other vertebrates, including a columbtform bird and various invertebrates, such as locusts and beetles were also taken. At Wikki, the single Bam Owl took slightly fewer mammals, but Tatera kempi , Taterillus gracilis and Mastomys erythroleucus as well as various shrews were the most important prey. The abundance of M. erythroleucus was probably much lower at Wikki than at Futuk, but the fairly high proportion of this rat in the diet of the owl is due probably to the semi-commensal nature of this raptor. Spotted Eagle-Owls obtained a much greater diversity of prey around Wikki, which may be due to the complexity of habitats. Here mammals were the major prey, especially by weight, but various reptiles, frogs and birds and large beetles were also taken (Table 4). In contrast, owls at Kaiban Hills mainly preyed upon scorpions and beetles and the majority of the vertebrate prey was made up of small numbers of reptiles, Including a chamaeleon and a small snake (possibly a file snake, Mehelya or Gonisonotophis) .
