The timing of hunting in short-eared owls ( Asio flammeus ) in relation to the activity patterns of Orkney voles ( Microtus arvalis orcadensis )

摘要: Using radio-telemetry, short-term cycles of activity, with a period about 3 h, were detected in Orkney voles Microtus arvalis orcadensis and one short-eared owl Asio flammeus, their principal predator. Visual observations showed that owls from four adjacent nests had similar activity patterns. These tended to be synchronous both within between the two species. Short-eared thus appeared foraging optimally by timing hunting coincide peaks vole i.e. at times maximum potential yield. The extent diurnal varied seasonally. Daytime was conspicuous for only short spring early summer. Otherwise almost exclusively nocturnal. seasonal changes probably response variations diurnality, population size daylength. Harassment kleptoparasitism may have been additional influences interacted these factors determine preferred nocturnal hunting. In addition, it is possible energetic constraints breeding force hunt during daylight. Were males night then they not able provide enough food mate young time when nights are populations starting increase.