Planet of Birds

Mallard (Anas platyrhynchos) Science Article 6 abstract The steroid hormone testosterone (T) mediates the expression of many secondary sexual characters, including behaviors which in.uence male reproductive success. Testes are one of the major sources of androgens, in particular of T. Although a positive relationship between testes size and T levels could be hypothesized, it has […]

Mallard (Anas platyrhynchos) Science Article 11 abstract Qualitative descriptive information on both vocal and visual displays of waterfowl is abundant (e.g., Heinroth 1910, 1911: Lorenz 1953; Weidmann 1956; Johnsgard 1965; McKinney 1965a, 1969, 1970, and quantitive data are available for visual displays of a few species of ducks Abraham, R. L., The Condor 76(4):401-420 Download […]

Mallard (Anas platyrhynchos) Science Article 8 abstract The use of elevated covered nest sites for Mallard Anas platyrhynchos was studied in 1999-2003 on coastal lakes and ponds of different origin. Within the 5-year period, a total of 723 checks of nest sites were made. Nest site occupancy by Mallard was much higher on ponds (46.8 […]

Mallard (Anas platyrhynchos) Science Article 2 abstract Molecular genetic maps will provide insight into the genome organization and chromosomal localization of cloned genes and also a framework for the identification and localization ofmajor genes associated with economically important traits (Crittenden et al. 1993). The rapid progress being made in the development of genetic maps for […]

Mallard (Anas platyrhynchos) Science Article 5 abstract Mallards (Anus pkztyrhynchos) and American Wigeon (A. americana) were studied in Alabama from November through February 1983-85. Resting was the major activity of Mallards (39-54%) and feeding was the major activity of American Wigeon (45- 7 1%). Mallards increased feeding during the colder winter of 1983-84, but wigeon […]

Mallard (Anas platyrhynchos) Science Article 4 abstract It is a peculiarity of most species of ducks that in the early summer, shortly after the breeding season, the males moult and then assume a plumage which in coloration and form closely resembles that of the female. This is known as the ‘eclipse’ or ‘summer ‘ plumage. […]

Mallard (Anas platyrhynchos) Science Article 9 abstract Heterogeneity in food abundance allows a forager to concentrate foraging effort in patches that are rich in food. This might be problematic when food is cryptic, as the content of patches is unknown prior to foraging. In such case knowledge about the spatial pattern in the distribution of […]

Mallard (Anas platyrhynchos) Science Article 1 abstract Using data from two independent field experiments, we address whether pair formation in introduced mallards Anas platyrhynchos is associated with habitat quality, specifically food limitation at the brood stage. Based on the concentration of total phosphorous in the water, the study lakes were divided into two groups, poor’ […]

Mallard (Anas platyrhynchos) Science Article 10 abstract Mallard (Anas platyrhynchos) breeding densities in the prairie pothole habitat of eastern North Dakota during 1961-1980 varied from 2.28 birds/km2 in 1977 to 9.47 birds/km2 in 1963 and were correlated with pond abundance (r = 0.543, P < 0.05). The number of basins used by pairs declined with […]

Mallard (Anas platyrhynchos) Science Article 12 abstract A study of temporal trends in forced copulation was conducted in flight-pens with eight pairs of captive mallards to test the hypothesis that forced copulation is an evolved breeding strategy in waterfowl. Cheng, K. M.; Burns, J. T.; McKinney, F., Animal Behaviour 30:695-699 Download article download full text […]