The effect of limited visibility on vigilance behaviour and speed of predator detection: implications for the conservation of granivorous passerines

摘要: Foraging animals frequently change their pattern of vigilance when they move from a patch with clear view to one relatively obstructed view. This has been widely interpreted as compensation for reduced ability detect approaching predators in habitats. We test the extent which changes may compensate effect visibility on an animal's predators. measured vigilance, foraging and speed predator-response behaviours lone chaffinches Fringilla coelebs that fed seeds (800 per m2) scattered artificial stubble habitats (with either surroundings or view). On both treatments, individuals more rapid head-up rates responded quickly flying model sparrowhawk Accipiter nisus (P=0.04); did shorter food-search times (P=0.02). However, neither rate nor period varied obstruction. Based research previously published using this system, we suggest is because are constrained increase doing so largely determined by individually efficiency. Instead increased duration periods 13% visually treatment (long stubble) peck were lower. Despite presumed attempt visibility, had no response time fast-moving predator our experiment birds 24% slower respond long stubble. Rather than being maladaptive, increasing have related enhanced detection other types, example stalkers. Our results implications conservation wild granivorous birds. They support agroeconomic decisions affect micro-habitat structure over large scale could predation risk, habitat choice status