The winter feeding ecology of Avocets Recurvirostra avosetta on intertidal areas. II. Diet and feeding mechanisms

Ibis - Tập 137 Số 1 - Trang 99-108 - 1995
Francisco Moreira1
1Departamento de Zoologia e Antropologia, Faculdade de Ciências, Bloco C2, Universidade de lisboa, P-1700 Lisboa, Portugal

Tóm tắt

The diet and feeding methods of Avocets Recurvirostra avosetta using the most common feeding strategy (Normal Feeding Strategy) on emerged intertidal areas in the Tagus estuary, Portugal, were studied during two winters.Avocets using the Normal Feeding Strategy fed non‐selectively in the top 20 mm of sediment, ingesting prey bigger than a minimum threshold dimension of around 1.5 mm. Some mud was also ingested whilst feeding. Prey were captured by the mechanical action of the bill, and the estimated number of items captured per sweep was quite high (mean = 10.9 worms). Most of the biomass ingested by Avocets consisted of oligochaetes, spionid worms, Capitella capitata and small ragworms Nereis diversicolor.The estimated intake rate of Avocets suggested that the energy ingested during daylight hours did not represent a significant percentage of the daily requirements. Thus, feeding on emerged intertidal areas is probably a secondary component of their daily gross food intake, unless night feeding yields higher intake rates due to increased prey availability.

Từ khóa


Tài liệu tham khảo

10.2307/3545008

10.1016/0077-7579(82)90017-5

Cramp S., 1983, The Birds of the Western Paleartic

Fauvel P., 1975, Faune de France, 5, Polychètes Errantes

Fauvel P., 1977, Faune de France, 16, Polychètes Sédentaires

Garwood P.R., 1981, Polychaeta. Errantia. Report of the Dove Marine Laboratory, 3rd series, No. 22

10.2307/1352696

Gray J.S., 1981, The Ecology of Marine Sediments: An introduction to the structure and function of benthic communities

Hötker H., 1991, Report on Ecological Studies on Avocets and Other Wetland Birds in the Delta of River Senegal in 1988, with Special Reference to the “Réserve Spécial de Faune de Guembeul”

Kersten M., 1987, High levels of energy expenditure in shorebirds; metabolic adaptations to an energetically expensive way of life, Ardea, 75, 175

Moreira F., 1993, Macrohabitat selection by waders in the Tagus estuary (Portugal), Port. Zool., 2, 1

10.1111/j.1474-919X.1995.tb03224.x

10.2307/1942620

Pearson T.H., 1978, Macrobenthic succession in relation to organic enrichment and pollution of the marine environment, Oceanogr. Mar. Biol. Annu. Rev., 16, 229

10.1007/BF00397050

10.2307/1941415

Siegel S., 1988, Nonparametric Statistics for the Behavioral Sciences

Sokal P.R., 1981, Biometry

10.1577/1548-8659(1979)108<344:REFIEI>2.0.CO;2

10.1016/0025-326X(85)90565-X

10.3354/meps083113

Thông tin
Thông tin xuất bản

Ibis

Tập 137 Số 1

99-108

Thông tin tác giả