Experimental functional response and inter-individual variation in foraging rate of teal (Anas crecca).
The functional response, i.e. the change in per capita food intake rate per time unit with changed food availability, is a widely used tool for understanding the ecology and behaviour of animals. However, waterfowl remain poorly explored in this context. In an aviary experiment we derived a functional response curve for teal (Anas crecca) foraging on rice (Oryza sativa) seeds. We found a linear relationship between intake rate and seed density, as expected for a filter-feeder. At high seed densities we found a threshold, above which intake rate still increased linearly but with a lower slope, possibly reflecting a switch from filter-feeding to a scooping foraging mode. The present study shows that food intake rate in teal is linearly related to food availability within the range of naturally occurring seed densities, a finding with major implications for management and conservation of wetland habitats.
Arzel
C
C
Office National de la Chasse et de la Faune Sauvage, CNERA Avifaune Migratrice, La Tour du Valat, Le Sambuc, F-13200 Arles, France. celine_arzel@yahoo.fr
Guillemain
M
M
Gurd
D B
DB
Elmberg
J
J
Fritz
H
H
Arnaud
A
A
Pin
C
C
Bosca
F
F
D000818:Animals; D003247:Conservation of Natural Resources; D004372:Ducks / Q000502:physiology*; D004435:Eating / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005523:Food Supply