Tag: all of Anas

Movements of a nomadic waterfowl, Grey Teal Anas gracilis, across inland Australia ? results from satellite telemetry spanning fifteen months

Grey Teal (Anas gracilis) Science Article 1 abstract We used lightweight satellite transmitters to follow the movements of 17 Grey Teal Anas gracilis between September 2003 and November 2004 in two contrasting landscapes, the agricultural districts of southern Australia and the desert landscapes of the interior. Roshier D.A., Klomp N.I. and Asmus M., Ardea 94(3): […]

A tangled tale of two teal: population history of the grey Anas gracilis and chestnut teal A. castanea of Australia

Grey Teal (Anas gracilis) Science Article 2 abstract Two Australian species of teal (Anseriformes: Anatidae: Anas), the grey teal Anas gracilis and the chestnut teal A. castanea, are remarkable for the zero or near-zero divergence recorded between them in earlier surveys of mitochondrial DNA (mtDNA) diversity. We confirmed this result through wider geographical and population […]

A tangled tale of two teal: population history of the chestnut teal Anas castanea and grey teal Anas gracilis of Australia

Chestnut Teal (Anas castanea) Science Article 1 abstract Two Australian species of teal (Anseriformes: Anatidae: Anas), the grey teal Anas gracilis and the chestnut teal A. castanea, are remarkable for the zero or near-zero divergence recorded between them in earlier surveys of mitochondrial DNA (mtDNA) diversity. We confirmed this result through wider geographical and population […]

Variation of pecking rate with sward height in wild wigeon Anas penelope

Wigeon (Anas penelope) Science Article 2 abstract We examined how pecking rate changed with sward height in wintering European wigeon Anas penelope in a nature reserve of the French Atlantic coast. Pecking rates were recorded as the time taken to perform 10 or 50 pecks. We found a negative correlation between pecking rate and sward […]

Feeding behaviour of breeding Wigeon Anas penelope in relation to seasonal emergence and swarming behaviour of chironomids.

Wigeon (Anas penelope) Science Article 3 abstract Emergence of chironomids started in mid-April, and reached a peak at the end of April and in the beginning of May. Most ‘spring’ chironomids emerged around noon, whereas the majority of chironomids emerging later in the season, appeared at night. In general, there was a positive correlation between […]

Constraints of feeding on Salicornia ramosissimaby wigeonAnas penelope: an experimental approach

Wigeon (Anas penelope) Science Article 1 abstract The coastal marshes of the Charente-Maritime (western France) are a major wintering area for wigeon Anas penelope. In these marshes, wigeon feed mainly on grasses, while foraging on Salicornia (a .eshy, succulent halophyte) is uncommon. In order to understand the reason for this under-exploitation, an experimental study was […]

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 […]

Vocalizations of the mallard (Anas platyrhynchos)

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 […]

Elevated artifi cial nest sites for Mallard Anas platyrhynchos in Latvia

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 […]