TY - JOUR
T1 - Intake rates and the functional response in shorebirds (Charadriiformes) eating macro-invertebrates
AU - Goss-Custard, J.D.
AU - West, A.D.
AU - Yates, M.G.
AU - Caldow, R.W.G.
AU - Stillman, R.A.
AU - Bardsley, L.
AU - Castilla, J.
AU - Castro, M.
AU - Dierschke, V.
AU - Durell, S.E.A.L.V.
AU - Eichhorn, G.
AU - Ens, B.J.
AU - Exo, K.M.
AU - Udayangani-Fernando, P.U.
AU - Ferns, P.N.
AU - Hockey, P.A.R.
AU - Gill, J.A.
AU - Johnstone, I.
AU - Kalejta-Summers, B.
AU - Masero, J.A.
AU - Moreira, F.
AU - Nagarajan, R.V.
AU - Owens, I.P.F.
AU - Pacheco, C.
AU - Perez-Hurtado, A.
AU - Rogers, D.
AU - Scheiffarth, G.
AU - Sitters, H.
AU - Sutherland, W.J.
AU - Triplet, P.
AU - Worrall, D.H.
AU - Zharikov, Y.
AU - Zwarts, L.
AU - Pettifor, R.A.
PY - 2006
Y1 - 2006
N2 - As field determinations take much effort, it would be useful to be able to predict easily the coefficients describing the functional response of free-living predators, the function relating food intake rate to the abundance of food organisms in the environment. As a means easily to parameterise an individual-based model of shorebird Charadriiformes populations, we attempted this for shorebirds eating macro-invertebrates. Intake rate is measured as the ash-free dry mass (AFDM) per second of active foraging; i.e. excluding time spent on digestive pauses and other activities, such as preening. The present and previous studies show that the general shape of the functional response in shorebirds eating approximately the same size of prey across the full range of prey density is a decelerating rise to a plateau, thus approximating the Holling type II ('disc equation') formulation. But field studies confirmed that the asymptote was not set by handling time, as assumed by the disc equation, because only about half the foraging time was spent in successfully or unsuccessfully attacking and handling prey, the rest being devoted to searching. A review of 30 functional responses showed that intake rate in free-living shorebirds varied independently of prey density over a wide range, with the asymptote being reached at very low prey densities (
AB - As field determinations take much effort, it would be useful to be able to predict easily the coefficients describing the functional response of free-living predators, the function relating food intake rate to the abundance of food organisms in the environment. As a means easily to parameterise an individual-based model of shorebird Charadriiformes populations, we attempted this for shorebirds eating macro-invertebrates. Intake rate is measured as the ash-free dry mass (AFDM) per second of active foraging; i.e. excluding time spent on digestive pauses and other activities, such as preening. The present and previous studies show that the general shape of the functional response in shorebirds eating approximately the same size of prey across the full range of prey density is a decelerating rise to a plateau, thus approximating the Holling type II ('disc equation') formulation. But field studies confirmed that the asymptote was not set by handling time, as assumed by the disc equation, because only about half the foraging time was spent in successfully or unsuccessfully attacking and handling prey, the rest being devoted to searching. A review of 30 functional responses showed that intake rate in free-living shorebirds varied independently of prey density over a wide range, with the asymptote being reached at very low prey densities (
KW - oystercatchers haematopus-ostralegus
KW - bivalve macoma-balthica
KW - mussels mytilus-edulis
KW - knots calidris-canutus
KW - tringa-totanus l
KW - plovers pluvialis-squatarola
KW - whimbrels numenius-phaeopus
KW - ragworm nereis-diversicolor
KW - cockles cerastoderma-edule
KW - wading bir
U2 - 10.1111/j.1469-185X.2006.tb00216.x
DO - 10.1111/j.1469-185X.2006.tb00216.x
M3 - Article
SN - 1464-7931
VL - 81
SP - 501
EP - 529
JO - Biological Reviews
JF - Biological Reviews
IS - 4
ER -