Le comportement des jeunes faucons hobereaux Falco subbuteo après leur envol

摘要: From 1982 to 2000, we studied the life of juvenile Hobbies after fledging, in Alsace (North East France). The study area covers hilly and flat terrain with following characteristics: from 100 450 m above sea level, tree cover 15 20%, dominant maize cultivation a population density 260 habitants per km 2 . A total 374 pairs producing 730 fledged juveniles were recorded on six quadrats ranging 70 165 each. mean fledging date was August 19 th (range: 5 - September 17 , n = 117) leaving 21 st October 3 rd 21). average stay 33 days big between family differences relation habitats years. No noted tree- pylon-dwelling pairs. Forty-five families (20 pylon- 25 tree-dwellers) monitored intensively 1983 1989 (245 hours field work) order produce detailed their behaviour. Family cohesion remained high until they departed migration. Adults leave probably just before juveniles. Until three weeks ofter are not very active: spend 4/5 time resting or preening. They closely attached breeding sites, even at end season when move up 1,000m away come back near nest rest. learning flight hunting techniques is gradual: first insects hunts day exchanges preys plucking 8 attempts bats some specialised (13%) 29 day. However, regular songbirds only takes place Europe although take 28 (four records seven years). male played most important role feeding youngs. But he female took also part this activity late season, least for instead lower level than male. both adults defend offspring by mobbing all raptors corvids less 300 away: react 65% contacts species (n 49). Common Buzzard, Eurasian Kestrel Carrion Crow mobbed often. Past aggressively diminishes markedly (reaction 3% contacts, 30). Mortality among negligible: 0.5 0.8% 374) due predation Pegrine Falcon (two cases) electrocution (only one case despite 44% using pylons as sites). Two notable behaviours recorded: fostering (18%) participation helpers rearing (one proven concerning an immature bird). In Peregrine well documented. Within European Falcon, Hobby seems have intermediate position. Everything indicate that mainly insectivorous, songbird captures happening energy input required breeding.