Tag: all of Anas

Activity budgets of mallards and american wigeon wintering in east-central Alabama

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 […]

On the eclipse plumage of the mallard (Anas platyrhyncha platyrhyncha)

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. […]

Prior knowledge about spatial pattern affects patch assessment rather than movement between patches in tactile-feeding mallard

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 […]

Pair formation among experimentally introduced mallards Anas platyrhynchos reflects habitat quality

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’ […]

Testosterone and testes size in mallards ( Anas platyrhynchos)

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 […]

THE EFFECT OF VARIABLE SPRING WATER CONDITIONS ON MALLARD REPRODUCTION

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 […]

Forced copulation in captive mallards (Anas platyrhynchos): II. temporal factors

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 […]

Male and female reproductive tactics in mallards (anas platyrhynchos l.): sperm competition and cryptic female choice

Mallard (Anas platyrhynchos) Science Article 7 abstract Mallards, Anas platyrhynchos, are among the most common waterfowl species in theNorthern Hemisphere. Despite their abundance and despite growing interest of behavioralecologists and evolutionary biologists in key aspects of their behavior, few studies haveused genetic tools to investigate their mating system. We studied the breeding biology ofmallards by […]

A Comparison of Two Methods to Establish the Prevalence of Lead Shot Ingestion in Mallards (Anas platyrhynchos) from The Netherlands

Mallard (Anas platyrhynchos) Science Article 3 abstract Two collection methods for screening the mallard (Anas platyrhynchos) population in the Netherlands for the ingestion of spent lead shot were compared. One method consisted of examination of gizzards from mallards shot by hunters (n 2,859) and the other method consisted of examination of gizzards from mallards caught […]

Characterization of Northern pintail ( Anas acuta) ejaculate and the effect of sperm preservation on fertility

Northern Pintail (Anas acuta) Science Article 1 abstract Northern pintail duck semen and sperm traits were characterized, and the fertility of cold-stored spermatozoa was investigated using artificial insemination. Excellent qualityejaculates containing high proportions of motile spermatozoa were collected from drakes within 20 s by a massage technique. Semen was collected in Beltsville poultry semen extender, […]