| 1. |
- Arzel, C., et al.
(författare)
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A flyway perspective of foraging activity in Eurasian Green-winged Teal, Anas crecca crecca
- 2007
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Ingår i: Canadian Journal of Zoology. - 0008-4301 .- 1480-3283. ; 85:1, s. 81-91
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Tidskriftsartikel (refereegranskat)abstract
- Time-activity budgets in the family Anatidae are available for the wintering and breeding periods. We present the first flyway-level study of foraging time in a long-distance migrant, the Eurasian Green-winged Teal, Anas crecca crecca L., 1758 ("Teal"). Behavioral data from early and late spring staging, breeding, and molting sites were collected with standardized protocols to explore differences between the,sexes, seasons, and diel patterns. Teal foraging activity was compared with that of the Mallard, Anas platyrhynchos L., 1758 and Northern Shoveler, Anas clypeata L., 1758, and the potential effects of duck density and predator-caused disturbance were explored. In early spring, foraging time was moderate (50.5%) and mostly nocturnal (45%). It increased dramatically in all three species at migration stopovers and during molt, mostly because of increased diurnal foraging, while nocturnal foraging remained fairly constant along the flyway. These patterns adhere to the "income breeding" strategy expected for this species. No differences between the sexes were recorded in either species studied. Teal foraging time was positively correlated with density of Teal and all ducks present, but negatively correlated with predator disturbance. Our study suggests that Teal, in addition to being income breeders, may also be considered as income migrants; they find the energy necessary to migrate at staging sites along the flyway.
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| 2. |
- Arzel, C., et al.
(författare)
-
A flyway perspective of foraging activity in Eurasian Green-winged Teal, Anas crecca crecca
- 2007
-
Ingår i: Canadian Journal of Zoology. - : National Research Council of Canada. - 0008-4301 .- 1480-3283. ; 85:1, s. 81-91
-
Tidskriftsartikel (refereegranskat)abstract
- Time-activity budgets in the family Anatidae are available for the wintering and breeding periods. We present the first flyway-level study of foraging time in a long-distance migrant, the Eurasian Green-winged Teal, Anas crecca crecca L., 1758 ("Teal"). Behavioral data from early and late spring staging, breeding, and molting sites were collected with standardized protocols to explore differences between the,sexes, seasons, and diel patterns. Teal foraging activity was compared with that of the Mallard, Anas platyrhynchos L., 1758 and Northern Shoveler, Anas clypeata L., 1758, and the potential effects of duck density and predator-caused disturbance were explored. In early spring, foraging time was moderate (50.5%) and mostly nocturnal (45%). It increased dramatically in all three species at migration stopovers and during molt, mostly because of increased diurnal foraging, while nocturnal foraging remained fairly constant along the flyway. These patterns adhere to the "income breeding" strategy expected for this species. No differences between the sexes were recorded in either species studied. Teal foraging time was positively correlated with density of Teal and all ducks present, but negatively correlated with predator disturbance. Our study suggests that Teal, in addition to being income breeders, may also be considered as income migrants; they find the energy necessary to migrate at staging sites along the flyway.
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| 3. |
- Arzel, Celiné, et al.
(författare)
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Experimental functional response and inter-individual variation in foraging rate of teal (Anas crecca)
- 2007
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Ingår i: Behavioural Processes. - 0376-6357 .- 1872-8308. - 0376-6357 ; 75:1, s. 66-71
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Tidskriftsartikel (refereegranskat)abstract
- The functional response, i.e. the change in per capita food intake rate per time unit with changed food availability, is a widely used too] 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.
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| 4. |
- Arzel, Celiné, et al.
(författare)
-
Experimental functional response and inter-individual variation in foraging rate of teal (Anas crecca)
- 2007
-
Ingår i: Behavioural Processes. - : Elsevier. - 0376-6357 .- 1872-8308. ; 75:1, s. 66-71
-
Tidskriftsartikel (refereegranskat)abstract
- The functional response, i.e. the change in per capita food intake rate per time unit with changed food availability, is a widely used too] 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.
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