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Titolo:
The effects of food availability and distance to protective cover on the winter foraging behaviour of tits (Aves : Parus)
Autore:
Walther, BA; Gosler, AG;
Indirizzi:
Univ Copenhagen, Museum Zool, DK-2100 Copenhagen O, Denmark Univ Copenhagen Copenhagen Denmark O Zool, DK-2100 Copenhagen O, Denmark Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England Univ Oxford Oxford England OX1 3PS eld Ornithol, Oxford OX1 3PS, England Konrad Lorenz Inst Vergleichende Verhaltensforsch, A-1160 Vienna, Austria Konrad Lorenz Inst Vergleichende Verhaltensforsch Vienna Austria A-1160
Titolo Testata:
OECOLOGIA
fascicolo: 2, volume: 129, anno: 2001,
pagine: 312 - 320
SICI:
0029-8549(200110)129:2<312:TEOFAA>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
BLACK-CAPPED CHICKADEE; FEEDING SITE SELECTION; PREDATION-RISK; WILLOW TITS; GREAT TIT; TRADE-OFF; FIELD EXPERIMENTS; FLOCKS; POPULATION; VIGILANCE;
Keywords:
optimal foraging; anti-predator behaviour; winter flocks; discrimination; experiment;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
53
Recensione:
Indirizzi per estratti:
Indirizzo: Walther, BA Univ Copenhagen, Museum Zool, Univ Parken 15, DK-2100 Copenhagen O, Denmark Univ Copenhagen Univ Parken 15 Copenhagen Denmark O , Denmark
Citazione:
B.A. Walther e A.G. Gosler, "The effects of food availability and distance to protective cover on the winter foraging behaviour of tits (Aves : Parus)", OECOLOGIA, 129(2), 2001, pp. 312-320

Abstract

To maximize fitness, many animals must trade off their need to forage efficiently against their need to avoid predators. We studied such a trade-off in four species of tits (Paridae) in a forest near Oxford, UK. During winter, tits form flocks which increase feeding efficiency and reduce predation risk. These flocks feed extensively on beech (Fagus sylvatica) seeds, the abundance of which may be critical for winter survival. Because these seeds drop to the ground, where birds are exposed to sparrowhawk (Accipiter nisus) attack, tits need to trade off their need to find seeds against the proximity to protective cover, provided by dense clusters of hawthorn (Crataegusspp.). The quality of the beech crop differs markedly between trees and years. During a year of abundant beechmast, most tits searched for seeds close to protective cover. This 'safety-first' strategy precluded visits to superabundant food patches if they were too far from protective cover. Among beech trees near to cover, tits tended to prefer those with high seed density. Tits benefited from foraging under trees with high seed density because this correlated significantly with seed mass per square metre and because mean search times decreased with increasing seed density. Finally, we show experimentally that great tits, Parus major, can discriminate between edible(viable) and inedible (empty) seeds.

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Documento generato il 03/04/20 alle ore 06:42:14