We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Individual variation in intake rate: the relative importance of foraging efficiency and dominance.
- Authors
Stillman, R. A.; Caldow, R. W. G.; Goss-Custard, J. D.; Alexander, M. J.
- Abstract
Summary: 1. Individual variation in the intake rate of foraging animals arises largely from variation in two characteristics: their intrinsic ability to forage in the absence of competitors (foraging efficiency) and the detrimental effect of competitors on their intake rate (susceptibility to interference). We use a model to explore the relative importance of foraging efficiency and dominance, which influences susceptibility to interference, in determining the intake rate of foraging animals at a range of competitor densities. 2. The model is parameterized and tested for a shorebird–prey system, oystercatchers Haematopus ostralegus L. feeding on mussels Mytilus edulis L., in which interference occurs because dominant individuals steal prey from subdominant ones. In both oystercatchers which open mussels by stabbing their bill between the shell valves (stabbers) and those which hammer a hole through the shell (hammerers), foraging efficiency is predicted to be the major determinant of intake rate at competitor densities below 100–150 birds ha[sup -1] and dominance the major determinant at higher densities. In reality, a very similar relationship is found in stabbers, but in hammerers foraging efficiency remains the most important determinant of intake rate across the full range of observed competitor densities, in contrast to the model’s prediction. Oystercatchers typically forage at densities in the range 100–250 birds ha[sup -1], in the region in which foraging efficiency and dominance are of approximately equal importance to stabbers, while foraging efficiency is most important to hammerers. We suggest reasons for the difference in the model’s predictive power for stabbers and hammerers. 3. We use the model to make the general predictions that the relative importance of foraging efficiency is higher when (i) it varies more between individuals, (ii) prey encounter rate is high, (iii) handling time is short, (iv) prey ste...
- Subjects
ANIMAL feeding behavior; COMPETITION (Biology); ANIMAL ecology
- Publication
Journal of Animal Ecology, 2000, Vol 69, Issue 3, p484
- ISSN
0021-8790
- Publication type
Article
- DOI
10.1046/j.1365-2656.2000.00410.x