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Titolo:
Foraging ecology of the South Australian glossy black-cockatoo (Calyptorhynchus lathami halmaturinus)
Autore:
Pepper, JW; Male, TD; Roberts, GE;
Indirizzi:
Univ Michigan, Museum Zool, Ann Arbor, MI 48109 USA Univ Michigan Ann Arbor MI USA 48109 Museum Zool, Ann Arbor, MI 48109 USA Univ Hawaii, Dept Zool, Honolulu, HI 96822 USA Univ Hawaii Honolulu HI USA 96822 waii, Dept Zool, Honolulu, HI 96822 USA
Titolo Testata:
AUSTRAL ECOLOGY
fascicolo: 1, volume: 25, anno: 2000,
pagine: 16 - 24
SICI:
1442-9985(200002)25:1<16:FEOTSA>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Keywords:
Allocasuarina verticillata; conservation; diet; distribution; feeding profitability; feeding rate; Kangaroo Island; seeds;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Pepper, JW Santa Fe Inst, 1399 Hyde Pk Rd, Santa Fe, NM 87501 USA Santa FeInst 1399 Hyde Pk Rd Santa Fe NM USA 87501 M 87501 USA
Citazione:
J.W. Pepper et al., "Foraging ecology of the South Australian glossy black-cockatoo (Calyptorhynchus lathami halmaturinus)", AUSTRAL EC, 25(1), 2000, pp. 16-24

Abstract

The endangered South Australian glossy black-cockatoo (Calyptorhynchus lathami halmaturinus Mathews 1912) feeds almost exclusively on the seeds of the drooping sheoak (Allocasuarina verticillata), and shows marked preferences for individual trees. This field study investigated foraging ecology and tree selection through observations of foraging birds and measurements of trees and seed cones. The cockatoos spent the vast majority of their foraging time (94%) handling seed cones, and handling behaviour was highly stereotyped. Handling time per cone was correlated primarily with cone size, whileseed intake rate was correlated primarily with seed mass per cone. The cockatoos fed mostly in trees with signs of previous feeding. They tended initially to sample trees with large seeds, and to stay for long feeding bouts in trees with high ratios of seed-to-cone mass. As a result of these biases, feeding was concentrated in trees with high seed mass per cone. Preferredtrees were also larger, with higher ratios of seed-to-cone mass and largerseeds containing more lipid and protein. By feeding from selected trees the cockatoos increased both their seed intake rate and the nutritional quality of the seeds ingested, thereby increasing their energy intake rate by anestimated 28%. They did not discriminate against trees that had re-grown from basal shoots after fires. Insect larvae were present in some seed conesbut the cockatoos did not appear to actively seek them. Males foraged 19% more efficiently than females, resulting in greater daily food intake. The characteristics of individual A. verticillata trees that determined the cockatoos' feeding rates were also correlated with their distribution on a regional scale. This suggests that the distribution of this endangered cockatoo depends not only on the presence of food trees, but also on their regionally varying feeding profitability.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 20:17:18