Roosting

Communal roosts can reach extraordinary scales — some European starling roosts hold over 40 million birds. Birds select roost sites that minimize heat loss (dense vegetation, cliff faces), reduce predation risk (over water, in thorny scrub), and facilitate information exchange about distant food sources. Roost sites are often philopatric, used by successive generations. Bat-eared foxes, mustelids, and owls specialize in hunting roost arrivals at dawn and dusk, making approach routes particularly hazardous.