Weights of Wild Mallard Anas platyrynchos, Gadwall A. strepera, and Blue-winged Teal A. discors During the Breeding Season
John T. Lokemoen, Douglas H. Johnson, and David E. Sharp
Abstract: During 1976-81 we weighed several thousands of wild Mallard, Gadwall, and Blue-winged Teal in central North Dakota to examine duckling growth patterns, adult weights, and the factors influencing them. One-day-old Mallard and Gadwall averaged 32.4 and 30.4 g, respectively, a reduction of 34% and 29% from fresh egg weights. In all three species, the logistic growth curve provided a good fit for duckling growth patterns. Except for the asymptote, there was no difference in growth curves between males and females of a species. Mallard and Gadwall ducklings were heavier in years when wetland area was extensive or had increased from the previous year. Weights of after-second-year females were greater than yearlings for Mallard but not for Gadwall or Blue-winged Teal. Adult Mallard females lost weight continuously from late March to early July. Gadwall and Blue-winged Teal females, which nest later than Mallard, gained weight after spring arrival, lost weight from the onset of nesting until early July, and then regained some weight. Females of all species captured on nests were lighter than those captured off nests at the same time. Male Mallard weights decreased from spring arrival until late May. Male Gadwall and Blue-winged Teal weights increased after spring arrival, then declined until early June. Males of all three species then gained weight until the end of June. Among adults, female Gadwall and male Mallard and Blue-winged Teal were heavier in years when wetland area had increased from the previous year; female Blue-winged Teal were heavier in years with more wetland area.
This resource is based on the following source (Northern Prairie Publication 791):
Lokemoen, John T., Douglas H. Johnson, and David E. Sharp. 1990. Weights
of wild mallard Anas platyrhynchos, gadwall A. strepera, and blue-
winged teal A. discors during the breeding season. Wildfowl 41:122-130.
This resource should be cited as:
Lokemoen, John T., Douglas H. Johnson, and David E. Sharp. 1990. Weights
of wild mallard Anas platyrhynchos, gadwall A. strepera, and blue-
winged teal A. discors during the breeding season. Wildfowl 41:122-130.
Jamestown, ND: Northern Prairie Wildlife Research Center Online.
http://www.npwrc.usgs.gov/resource/birds/duckwght/index.htm
(Version 30DEC2002).
Table of Contents
- Introduction
- Methods
- Results
- Weights of eggs and hatchlings
- Growth of ducklings
- Flying young
- Discussion
- Weights of eggs and hatchlings
- Growth of ducklings
- Flying young
- Variation in adult weights by sex and age
- Seasonal change in adult weights
- Annual variation in adult weights
- Acknowledgments
- References
Tables and Figures
- Table 1 -- Average weights, sample sizes, and standard deviations of Mallard eggs and ducklings, by sex and age.
- Table 2 -- Average weights, sample sizes, and standard deviations of Gadwall eggs and ducklings, by sex and age.
- Table 3 -- Average weights, sample sizes, and standard deviations of Blue-winged Teal eggs and ducklings, by sex and age.
- Table 4 -- Estimates of parameters of the logistic equation fitted to weights of Mallard, Gadwall, and Blue-winged Teal flightless ducklings.
- Figure 1 -- Logistic curves fitted to weights of flightless Mallard, Gadwall, and Blue-winged Teal ducklings and projected to age 100 days, by sex.
- Figure 2 -- Weights of known-age female Gadwall ducklings plotted against fitted logistic growth curve.
- Figure 3 -- Average weights of adult ducks by 10-day period of the breeding season, for three species.
- Figure 4 -- Average weights of adult ducks by year, for three species.
John T. Lokemoen, Douglas H. Johnson, and David E. Sharp, United States Department of the Interior, Fish and Wildlife Service, Northern Prairie Wildlife Research Center, Jamestown, North Dakota 58401.
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(122K) -- Weights of Wild Mallard Anas platyrynchos, Gadwall
A. strepera, and Blue-winged Teal A. discors During the Breeding
Season
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