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Titolo:
FLOCKING BEHAVIOR OF FORAGING BIRDS IN A NEOTROPICAL RAIN-FOREST AND THE ANTIPREDATOR DEFENSE HYPOTHESIS
Autore:
THIOLLAY JM; JULLIEN M;
Indirizzi:
ENS,ECOL LAB,46 RUE ULM F-75230 PARIS 05 FRANCE
Titolo Testata:
Ibis (London. 1859)
fascicolo: 3, volume: 140, anno: 1998,
pagine: 382 - 394
SICI:
0019-1019(1998)140:3<382:FBOFBI>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMMUNITY; ORGANIZATION; DENSITY; PANAMA; PARUS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
J.M. Thiollay e M. Jullien, "FLOCKING BEHAVIOR OF FORAGING BIRDS IN A NEOTROPICAL RAIN-FOREST AND THE ANTIPREDATOR DEFENSE HYPOTHESIS", Ibis (London. 1859), 140(3), 1998, pp. 382-394

Abstract

Randomly encountered foraging birds were recorded in a primary rain forest of French Guiana (13,550 records of 216 species), together with their size, diet and habitat use, to assess the relative frequencies of different types of flocking behaviour and some of their ecological correlates. Overall, 42% of birds foraged singly, primarily carnivores (raptors), nectarivores (hummingbirds) and lek-mating frugivores (manakins, some cotingas). Foraging in pairs (26.6%) was widespread, notably among insectivores in the 17-32-g size class. The remaining 31.4% ofrecords were birds in groups of different composition and function, including, in order of decreasing frequency (1) multispecies upper canopy flocks (83 member species identified)-the largest and most mobile associations of small insectivores, nectarivores and frugivores, mostlytanagers; (2) understorey mixed species flocks of small insectivores,at midlevels of closed forest interior, with 12 core, obligate members and 74 occasional species, mostly active foliage or bark gleaners and probers sharing a unique set of ecological characteristics; (3) monospecific groups (29 species), either gregarious foragers but solitary breeders (large frugivores in canopy) or also breeding colonially or several permanently group living cooperative breeders; (4) opportunistic gatherings of frugivores at fruiting trees (at least 40 species); (5) army ant followers near ground of closed understorey (29 species of mid- to large-sized insectivores); (6) followers of Red-throated Caracaras Daptrius americanus (23 species, usually canopy frugivores entering understorey with caracaras); (7) two raptors following monkeys. Attributes of vulnerability to predators defined by habitat structure (vegetation density or openness) and foraging behaviour (conspicuousness,speed, degree of vigilance) were important determinants of nocking propensity, at least in flocks that were not attracted by a particular food source. The results suggest that the permanent mixed-species necksin the mature forest understorey may be an antipredator defence to compensate for the conspicuousness and reduced vigilance resulting from active foraging behaviour in semi-open vegetation, where early detection of predators is difficult.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 16:26:24