Habitat selection as an antipredator behaviour in a multi-predator landscape: All enemies are not equal

1. Breeding territory choice constitutes a crucial antipredator behaviour for animals that determines reproductive success and survival during the breeding season. On arrival to breeding grounds migrant prey face a multitude of 'waiting' predators already settled within the landscape. 2. We studied territory selection and reproductive investment of migrant pied flycatcher (Ficedula hypoleuca) relative to breeding pygmy owls (POs) (Glaucidium passerinum) and Tengmalm's owls (TOs) (Aegolius funereus). Diurnal POs present a greater predation threat to adult flycatchers (up to 80% songbirds in diet) compared with nocturnal TOs (up to 36%). 3. During territory selection, pied flycatchers strongly avoided POs (occupation: 42% in presence vs. 92% in absence of owl nest) but not TOs (80%vs. 75%). This suggests that flycatchers are able to distinguish between two potential predators, avoiding dangerous POs but not obviously responding to the less risky TOs. 4. Flycatchers responded to presence of PO nests with c. 4-day delay in the start of egg-laying. A significantly prolonged nest building period contributed to this potentially costly breeding delay. Flycatchers further significantly reduced initial reproductive investment in presence of POs by laying 8·2% smaller clutch sizes, even if laying date was controlled. No breeding delay and clutch size reduction was found relative to TO presence. 5. Our results highlight flexibility in breeding territory selection and reproductive strategies as antipredator responses to perceived risk in a multi-predator environment. This supports the idea that for prey, not all predators are equal. ©2009 The Authors. Journal compilation ©2009 British Ecological Society.