The 1975 mid-winter waterfowl survey (Goldsberry et al. 1980) recorded 

 about 152,600 wintering Ruddy Ducks in the United States and Mexico; an esti- 

 mated additional 64,500 had been killed during the preceding hunting season. 

 Of those surveyed, 43% were in the Pacific Flyway, 2% were in the Central Fly- 

 way, 7% were in the Mississippi Flyway, 39% were in the Atlantic Flyway, and 

 9% were in Mexico. About 16% (ca. 24,500 birds) wintered in the southeastern 

 United States. The largest wintering populations were in California (ca. 

 54,250 birds), Maryland (25,500), North Carolina (9,300), and Oregon (8,300). 

 Audubon Christmas Bird Counts (Map 32) suggest that larger winter concentra- 

 tions occur in southern Florida and Texas. 



Wintering populations elsewhere are not well known. Palmer (1976b) cited 

 Leopold's (1959) observation in 1952 of an estimated 107,700 Ruddy Ducks just 

 west of Acapulco in Guerrero, Mexico, and remarked that this population may have 

 have then represented more than a third of the entire North American population. 

 Unknown numbers winter in and perhaps south of Guatemala. Winter surveys in 

 the Caribbean have revealed about 100 birds (Bellrose 1976). The post-breeding 

 population of introduced Ruddy Ducks in England numbers in the low hundreds 

 (Hudson 1976). 



Migration Birds from the prairies tend to move to the coasts, particularly 

 the Pacific coast, funnelling into three major areas — the Great Salt Lake of 

 Utah, Minidoka NWR near Rupert, Idaho, and the Klamath Basin of California. 

 From these areas the birds move on to southern California and western Mexico. 

 Birds from the north central prairie states may move eastward to the Chesapeake 

 Bay or New England. Some apparently move directly south across the Great Plains 

 (Bellrose 1976). 



Within the contiguous United States spring migration occurs from early 

 March into May. Dispersal in the fall may occur as early as August but the pri- 

 mary movement to the wintering range occurs from early September to early Decem- 

 ber, with a peak in October. Ruddy Ducks wintering in Mexico arrive later and 

 depart earlier than do birds wintering farther north (Palmer 1976b). Most mi- 

 gration occurs at night in small flocks of five to fifteen birds (Bellrose 1976). 



HABITAT 



Nesting Ruddy Ducks nest in emergent vegetation in water about a foot 

 deep at the edges of prairie marshes (Bellrose 1976). Cattail ( Typha ) , bulrush 

 ( Scirpus ) , white top ( Scolochloa ) , and reeds ( Phragmites ) are all used when avail- 

 able (Bellrose 1976, Palmer 1976b). They nest on both large and small marshes 

 that range from potholes of less than an acre in extent to 1,200-acre sloughs. 

 The nest may be either a floating platform of vegetation or a platform built up 

 from the floor of the marsh. Nests also may be placed on old muskrat ( Ondatra 

 zibethica ) lodges or feeding platforms or on old coot ( Fulica americana ) nests. 

 Nests may be found either near shore or far from it, at the edge of the marsh 

 or concealed well within it (Bellrose 1976, Palmer 1976b, and authors cited 

 therein) . 



Feeding On the breeding grounds in southern Manitoba, Ruddy Ducks prefer 

 to feed in areas of shallow water near the edges of ponds (Siegfried 1973c). 



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