No description available.

I evaluated the use of various wetlands by wintering ducks in the Tulare Lake Basin (TLB), California, during October 1982 - April 1983 and September 1983 - March 1984. Aerial waterfowl counts of the TLB were used to document spacial use patterns by ducks. Ground surveys on evaporation ponds in the Tulare Lake Drainage District (TLDD) were used to evaluate duck use of specific ponds with varying chemical and biological parameters. During mid-winter, up to 300,000 ducks used the TLB. The most abundant species (northern pintail (Anas acuta), northern shoveler (Anas clvoeata), and green-winged teal (Anas crecca)) were found on freshwater habitats. Ruddy ducks (Oxvura jamaicensis) were the only species to extensively use the evaporation ponds. With the exception of ruddy ducks, the evaporation ponds did not appear to be valuable for feeding areas, but provided sanctuary during the hunting season. The use of evaporation ponds by waterfowl may be heavier in years without the extensive floodwater that was present during this study. / Graduation date: 1991

Six hundred day-old Pekin and Muscovy male ducklings were raised on diets based exclusively on food wastes to market ages of 7 and 11 weeks, respectively. Three dietary treatments were offered to the birds: commercial pellets (control), feeds consisting partially of food waste, and feeds consisting entirely of food waste. The two experimental treatments each had a dry pelleted diet and a wet mash diet. Twenty-four carcasses from each breed were analyzed to determine the effects of the experimental diets compared to those of the control (commercial pellets). In addition to corn and soybean meal, a total of nine food waste ingredients were tested. The precise-feeding technique was performed to establish DM, fat, and fibre digestibility as well as N retention, AME, AMEn, TME, TMEn values for the 11 feedstuff ingredients. The results of this study provide reliable data for formulation of duck diets using the tested food waste ingredients as well as corn and soybean meal in both Pekin and Muscovy ducklings at 2 different ages during growth. (Abstract shortened by UMI.)

Knowledge of carcass merit will help the meat duck breeder identify superior stock and accelerate genetic improvement. Selection for leanness will enhance product acceptance by the consumer. Heritability values for carcass traits are in the medium-high range. Feed intake level during rearing is critical for reproduction. The objectives were to evaluate (1) the response of breast muscle thickness of the F1 progeny from parent breeders selected for maximum muscle thickness at market age and (2) the effect of 2 levels of feed restriction during development for subsequent egg production. In a commercial flock, 4842 Pekin ducks (Brome Lake Ducks Ltd.) were individually weighed and measured by ultrasound for breast muscle thickness (MT, mm) at 47 days of age. Three groups of 120 females and 25 males each were selected and allocated to the following groups: (1) control (CT), randomly selected; (2) maximum body weight (BW), and (3) maximum MT. From 7 to 23 wk old, one half of breeders followed a conventional restriction (CR) at 67 g feed/kg body weight daily, the other half were slightly more restricted following a Macdonald restriction (MR) at the same intake as CR but with a weekly skip-a-day feeding. (Abstract shortened by UMI.)

Thesis (M.S.)--Texas Tech University, 1986. / Title from caption (viewed on Aug. 28, 2009). Title from document title page. Includes bibliographical references. Available in PDF format via the World Wide Web.

No description available.

No description available.

published_or_final_version / Zoology / Doctoral / Doctor of Philosophy

This thesis describes a series of studies to investigate the predator-prey relationships between the Goosander Mergus merganser, a fish-eating duck, and populations of game fish in northern Britain. The distribution and numbers of birds during the breeding season, in northern England and Scotland, were investigated and variations in density, between and within rivers, studied. Relationships between densities in spring and summer survey periods were also investigated. Possible biases in survey data are discussed. Studies of the growth of ducklings reared in captivity allowed estimates to be made of food and energy requirements from hatching up to approximately the time of fledging, at c70 days. Seasonal changes in the body mass and body condition of adult and immature Goosanders were investigated and daily and seasonal food and energy requirements estimated. Time-budget data were collected to investigate how birds partitioned their time between various behaviours. Of particular concern was the temporal and spatial distribution of foraging activities between and within broad habitat types, viz. rivers, standing waters known to be roost sites, and non-roost standing waters. Feeding behaviour was also recorded. The species composition of the diet and the numbers of individual fish represented, were determined by the gut analysis of 54 birds received from various sources. Possible biases in this method are discussed. For salmonids, the size of individual prey items was investigated from regression equations of fork length on vertebrae length, based on a reference collection. Conflicting evidence of damage to fisheries from other studies chiefly in North America, is re-assessed in the light of current knowledge of the population dynamics of salmonids and of results presented here. The potential contribution of depredations by Goosanders to mortality at successive life stages of fish is considered.

No description available.