Differential predation upon sex and age classes of tuco-tucos (Ctenomys talarum, Rodentia: Octodontidae) by owls

KITTLEIN, MARCELO J.; VASSALLO, ALDO I.; BUSCH, CRISTINA

MAMMALIAN BIOLOGY

Elsevier

Año: 2001 vol. 66 p. 281 - 289

1616-5047

Predation by burrowing (Athene cunicularia) and short-eared (Asio flammeus) owls upon sexes and age-classes of the subterranean herbivorous rodent Ctenomys talarum were studied by comparing characteristics of field-trapped and preyed-upon individuais. Owls took a greater proportion of males than females i n comparison with their respective field densities. This sex-biased pattern of predation was most marked during the breeding season of C. talarum and mainly affected subadult males. A set of ecological features of C, talarum, such as food habits and above ground mobility, that might explain differential vulnerability by sex was analysed and did not support the observed pattern. We suggest that it is determined by higher above ground exposure of subadult males during the breeding season because they interact above ground with adult males and search for settlement sites t o establish their own burrows.