Owl predation in two sympatric species of Ctenomys

BUSCH, CRISTINA; KITTLEIN MJ; VASSALLO, ALDO IVÁN

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Lugar: Lawrence; Año: 1994 vol. 75 p. 725 - 732

0022-2372

Predation by owls upon two sympatric species of subterranean rodents of the genus Cten- omys was studied by comparing characteristics of individuals that were field-trapped and preyed upon. Predators took a greater proportion of the smaller C. talarum than of the larger C. australis in comparison to that estimated from their respective field densities. Only subadult individuals of C. australis were found among pellets. For C. talarum, a greater proportion of subadults than of adults was observed in pellets. We suggest that this pattern is determined both by constraints imposed by size of prey on the ability of a predator to handle large prey and by greater exposure of dispersing subadults to predation. Differ- ential predation possibly maintains the habitat segregation observed between C. talarum and C. australis.