Texas Waterfowl

Ruddy Duck

133 stripes; one stripe is through the eye and the other is below the eye. Their belly is white. Their tail is long and brownish, and they often hold it in an upright position. Adult males have a blue bill, and females have a slaty gray bill. Males and females weigh about 13.3 and 12.5 ounces, respectively. Nonbreeding: In both sexes this plumage is similar to the breeding plumage of adult females. SOURCES introduction: Johnsgard and Hagemeyer 1969. texas distribution: Johnsgard and Hagemeyer 1969; Blankenship and Anderson 1993; Lockwood 1997; Anderson et al. 1998; Anderson and Tacha 1999; Eitniear 1999, 2010; Benson and Arnold 2003; Lockwood and Freeman 2004; Eubanks et al. 2006. population status: Rappole et al. 2007. diet: Bellrose 1980; Johnsgard and Carbonell 1996; Eitniear 1999. range and habitats: Bowman 1995; Howell and Webb 1995; Johnsgard and Carbonell 1996; Anderson and Tacha 1999; Eitniear 1999; Eitniear and Colón-López 2005. reproduction : Johnsgard and Hagemeyer 1969; Johnsgard 1975; Gomez-Dallmeier and Cringan 1990; Johnsgard and Carbonell 1996; Eitniear 1999. appearance: Johnsgard 1975; Johnsgard and Carbonell 1996; Eitniear 1999. RUDDY DUCK Oxyura jamaicensis Compared to other waterfowl, Ruddy Ducks have extremely large eggs and a large total clutch weight. A single egg is equivalent to about 12 percent of a female’s body weight, and remarkably, the weight of all eggs in a clutch totals about 88 percent of a female’s weight. There are even records of individual females having a total clutch weight that exceeded their body weight. For comparison , average egg weight and clutch weight of a Mallard are about 6 percent and 46 percent, respectively, of a female’s body weight. The energy required for a Ruddy Duck to produce just one egg exceeds 300 percent of its normal daily energy demands. To meet the energy demands for egg production, female Ruddy Ducks forage voraciously. TEXAS DISTRIBUTION Breeding: Ruddy Ducks nest across much of Texas, including the High Plains,TransPecos , South Texas Brush Country, and Coastal Prairies. They are considered casual breeders in the High Plains, and most records are from playa wetlands. In a four-year study conducted in the 1970s, 108 adults and five broods were observed in 12 High stiff-tailed ducks 134 Plains counties. Nesting effort apparently increases when conditions are favorable, particularly in wetlands associated with the Rio Grande. Migration and Winter: Migrants occur throughout Texas.They arrive in most regions of the state by September or early October. During winter, the vast majority of Ruddy Ducks are found in the Coastal Prairies (TPWD unpublished). Most migrating and wintering Ruddy Ducks depart Texas by mid- to late May. TEXAS HARVEST From 1999 to 2006, harvest in Texas averaged 1,610 annually, which was about 6 percent of their annual US harvest. POPULATION STATUS From 1994 to 2003 their population was estimated to average 1.1 million annually. However, this estimate is speculative, as much of their breeding range is not surveyed . Ruddy Ducks are believed to have an increasing population. DIET Ruddy Ducks primarily forage by diving and searching for prey along the bottom. In California, 80 percent of the diet of breeding adults was midge larvae and leeches. Vegetation such as spikerush and seeds accounted for 38 percent of their winter diet in South Carolina. In spring, midge immatures and brine fly larvae accounted for 95 percent of their diet. Ruddy Duck (male). Photograph courtesy of Glenn Bartley/VIREO, taken May 19, 2009, British Columbia , Canada. 135 RANGE AND HABITATS Breeding: The extensive breeding range of Ruddy Ducks covers an area from southern Nunavut south to the Mexican Highlands.They also breed in the Caribbean and in South America, although many authorities give these Ruddy Ducks a subspecies status. They have been introduced to Europe. In North America they reach their peak breeding density in the Prairie Pothole and Parkland Regions. Breeding Ruddy Ducks settle in on semipermanent and permanent freshwater wetlands. Wetlands used for nesting typically have extensive emergent vegetation. Overwater nests are well concealed and typically located in emergent vegetation such as prairie whitetop and cattail. They occasionally nest on the ground in the immediate vicinity of wetlands. Migration and Winter: Migrants potentially occur on wetlands throughout North America. During winter, Ruddy Ducks are found across much of the United States, Mexico, and Central America. Ruddy Ducks use reservoirs, lakes, aquaculture wetlands , saline lakes, freshwater river deltas, coastal marshes, mangrove swamps, estuaries...