Diurnal Visibility and Activity of Blue-Winged Teal and Mallard Broods

Ringelman, James K.; Flake, Lester D.

doi:10.2307/3808310

Cited by 28 publications

(36 citation statements)

References 2 publications

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“…Remaining introduced birds and all wild waterfowl were counted on each visit, using the waterfowl point count method in Koskimies and Väisänen (1991). Most counts were made in the morning or in the evening, when duckling activity normally peaks (Ringelman and Flake 1980). No counts were made at night, and we also avoided very windy, rainy, hot, as well as cold weather.…”

Section: Waterfowl Countsmentioning

confidence: 99%

Experimental evidence for density-dependent survival in mallard (Anas platyrhynchos) ducklings

et al. 2006

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It is unresolved to what extent waterfowl populations are regulated by density-dependent processes. By doing a 2-year crossover perturbation experiment on ten oligotrophic boreal lakes we addressed the hypothesis that breeding output is density dependent. Wing-clipped mallard (Anas platyrhynchos) hens were introduced with their own brood and then monitored for 24 days. Predicted responses were that per capita duckling and hen survival would be lower in high-density than in low-density treatments. Survival was evaluated by model fitting in program MARK. Density, year, and lake were used as main effects, while day after introduction, a weather harshness index, and presence of hens were covariates. Daily survival in ducklings was lower in the high-density treatment, but this effect was year dependent. The highest-ranking model for duckling survival also included a positive effect of duckling age and presence of hens, and a negative effect of harsh weather. Density did not affect female survival although there was a prominent year effect. The highest-ranking model for female survival also included negative effects of day after introduction and harsh weather. This is the first study to report density-dependent survival in experimentally introduced ducklings in a natural setting. Implications for population dynamics and management of harvested populations are far-reaching if such regulation occurs in some years, but not in others.

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Section: Waterfowl Countsmentioning

confidence: 99%

Experimental evidence for density-dependent survival in mallard (Anas platyrhynchos) ducklings

et al. 2006

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“…Introduced foster females were readily told from wild females due to their lack of primary projection (wing tip) on one of the wings. Most counts were made in the morning or in the evening, when duckling foraging activity normally peaks (Ringelman and Flake 1980). No counts were made at night.…”

Section: Observation Of Introduced Birdsmentioning

confidence: 99%

Born to cope with climate change? Experimentally manipulated hatching time does not affect duckling survival in the mallard Anas platyrhynchos

Sjöberg

Gunnarsson

Pöysä³

et al. 2010

Eur J Wildl Res

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Two main hypotheses proposed to explain the seasonal decline in reproductive performance in birds are (1) deterioration of environmental conditions and (2) lower parental quality of late breeders. Previous experimental work addressing these hypotheses generally have problematic biases pertaining to delay of hatching, costs of re-laying and incubation, as well as variation in the quality of eggs, territories, offspring and parental traits. We address these biases in an experimental test of the timing hypothesis (i.e.(1) above) in a precocial bird. Using a 2-year cross-over design and game-farm mallard (Anas platyrhynchos) eggs originating from a number of hens and a standardised delay procedure, we introduced early and late broods with a foster female onto boreal oligotrophic lakes and monitored subsequent duckling survival. Standardised invertebrate sampling was done concurrently to get a measure of lake-level abundance of aquatic prey, a likely causative agent of putative seasonal difference in duckling survival. Survival data and covariates (duckling age; days) were analysed by an information theoretic approach. There was no effect of treatment (i.e. manipulation of hatching date) on duckling survival, which was higher in 2005 than in 2004. In contrast to observational studies from more seasonal wetlands, our experiment demonstrates that duckling survival on boreal lakes was not affected by a 12-day delay in hatching date. Since we did not find any consistent trends in abundance of aquatic prey, i.e. neither clear peaks nor differences between treatment periods, we hypothesise that moderate climate change has minor effects on resource abundance and hence also on mallard duckling survival in boreal environments.

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“…1-5-day-old ducklings (such as mallards), normally swim on the surface and forage by surface skimming and gleaning insects from emergent vegetation (e.g. Pehrsson, 1979;Ringelman and Flake, 1980). Although water temperature has the largest effect on metabolic rate, ambient air temperature significantly modifies heat loss.…”

Section: Heat Transfer Propertiesmentioning

confidence: 99%

“…Pehrsson, 1979;Ringelman and Flake, 1980). Despite its apparent ecological importance, thermoregulation of downy waterbird chicks during surface swimming has received limited attention (Eppley, 1984;Steen et al, 1989;Sutter and MacArthur, 1992).…”

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confidence: 99%

Partitioning heat loss from mallard ducklings swimming on the air–water interface

Banta

Lynott

VanSant

et al. 2004

Journal of Experimental Biology

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Diurnal Visibility and Activity of Blue-Winged Teal and Mallard Broods

Cited by 28 publications

References 2 publications

Experimental evidence for density-dependent survival in mallard (Anas platyrhynchos) ducklings

Experimental evidence for density-dependent survival in mallard (Anas platyrhynchos) ducklings

Born to cope with climate change? Experimentally manipulated hatching time does not affect duckling survival in the mallard Anas platyrhynchos

Partitioning heat loss from mallard ducklings swimming on the air–water interface

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