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Titolo:
The survival value of flocking in neotropical birds: Reality or fiction?
Autore:
Jullien, M; Clobert, J;
Indirizzi:
Ecole Normale Super, Ecol Lab, CNRS, URA 258, F-75230 Paris 05, France Ecole Normale Super Paris France 05 S, URA 258, F-75230 Paris 05, France Inst Ecol, CNRS, URA 258, F-75252 Paris, France Inst Ecol Paris France F-75252 col, CNRS, URA 258, F-75252 Paris, France
Titolo Testata:
ECOLOGY
fascicolo: 12, volume: 81, anno: 2000,
pagine: 3416 - 3430
SICI:
0012-9658(200012)81:12<3416:TSVOFI>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
MIXED-SPECIES FLOCKS; LIFE-HISTORY EVOLUTION; FORAGING FLOCKS; NEST PREDATION; INTERSPECIFIC COMPETITION; INDEPENDENT CONTRASTS; WILLOW TITS; GREAT TIT; TERRITORIALITY; BEHAVIOR;
Keywords:
adult survival; facultative flocking; foraging efficiency; life history traits; mixed-species flocks; neotropical forest; obligate flocking behavior, passerine; predator avoidance; tropics;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
113
Recensione:
Indirizzi per estratti:
Indirizzo: Jullien, M Univ Montana, Montana Cooperat Wildlife Res Unit, Avian StudiesProgram, Missoula, MT 59812 USA Univ Montana Missoula MT USA 59812 ram, Missoula, MT 59812 USA
Citazione:
M. Jullien e J. Clobert, "The survival value of flocking in neotropical birds: Reality or fiction?", ECOLOGY, 81(12), 2000, pp. 3416-3430

Abstract

Greater foraging efficiency and/or better predator avoidance have long been assumed and used as explanations for the evolution of flocking behavior in birds. Even if the debate between the validity of these two hypotheses remains open, one prediction is that living in flocks can favor increased survival rates. We gathered published and unpublished data from various tropical forests where bird species forage (1) exclusively alone or in pairs (2) in heterospecific flocks some of the time (facultative flock members), or (3) exclusively in heterospecific year-long associations (obligate flock members). We controlled statistically for effects of body size, nest type, clutch size, and phylogeny, and tested whether survival rates differed among these three groups. The survival rates of the obligate flock members (mean survival rate 68.7%, range 48.0-87.0%) were significantly higher than estimates for the species feeding alone or in pairs (mean survival rate 58.3%, range 33.0-79.0%). However, survival rates of the facultative hock members (mean survival rate 60.4%, range 40.0-79.0%) did not differ from those of thenonflocking species. Nevertheless, causes of such differences in survival can be explained by an alternative hypothesis. Life history theory predictsthat higher survival for the obligate flocking species may be a response to low fecundity and productivity. Yet, the pattern "high survivorship, strikingly low fecundity" documented in obligate flocking species has never been observed among their solitary or facultative flocking counterparts. This result suggests that permanent obligate flocking can be an alternative ecological factor that may drive the evolution of life histories in tropical birds.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 12:54:25