When nesting in wetter, more open sites, they prefer to nest on islets and low 

 promontories. Black Scoters will also nest on upland slopes, arctic-alpine 

 areas, and along the banks of rivers (Cramp et al. 1977). 



At Lake Myvatn, Iceland, these ducks nested predominantly under dense 

 shrubbery, primarily low rather than high shrubs. They nested to a much lesser 

 extent in holes, meadows, and among sedges. Most nests were within 10-100 ft 

 (3-30 m) of potholes and were well dispersed. The average nest-density was 53 

 nests/sq km (1 nest/5 acres [Bengtson 1970 iji Johnsgard 1975, Bellrose 1976]). 

 Black Scoters nested in the largest clumps of grass at Hooper Bay, Alaska 

 (Brandt 1943 in Bellrose 1976). 



Feeding Breeding birds presumably feed in waters near their nest sites; 

 wintering birds largely feed over shellfish beds in shallow waters. Cramp et 

 al. (1977) indicated that these scoters prefer to feed in waters about 1-3 m 

 (3.3-9.8 ft) deep. 



Winter and Offshore Non-breeding Black Scoters often form large flocks 

 comprised of several hundred to a thousand or more birds. These scoters are 

 usually found on marine waters, generally 500 m (1,640 ft) to 2 km (3.22 mi) 

 offshore over waters not more than 10-20 m (32.8-65.6 ft) deep. They prefer 

 open ocean just offshore to areas interspersed with rocks and islands (Cramp 

 et al. 1977). Johnsgard (1975) indicated that the optimum habitat along the 

 Atlantic coast was within a mile (ca. 1.6 km) of shore and just beyond the 

 breakers. During stormy weather Black Scoters sometimes seek sheltered waters 

 (Palmer 1976b). They rarely come ashore but may occasionally rest on islets 

 or sandbanks (Cramp et al. 1977). 



FOOD AND FEEDING BEHAVIOR 



Black Scoters feed by diving, usually by day in smaller scattered groups 

 than when roosting nocturnally (Cramp et al. 1977). They usually move inshore 

 to feed early in the morning (Phillips 1926 jjn Johnsgard 1975). Diving is of- 

 ten synchronized (Cramp et al. 1977). These scoters do not dive particularly 

 deeply; Cottam (1939 Jji Johnsgard 1978) believed that dives seldom exceeded 40 

 ft (12 m) . Cramp et al. (1977) indicated that these scoters may remain sub- 

 merged for as much as 49 sec but that dives usually take between 18 and 30 sec. 



We are unaware of any detailed accounts of food habits within the waters 

 of the southeastern United States. The following comments on foods eaten else- 

 where are largely abstracted from Palmer (1976b) and Cramp et al. (1977), who 

 should be consulted for more detailed listings of organisms eaten. 



In one study covering North America (Cottam 1939 in Palmer 1976b), Black 

 Scoters fed largely (ca. 90%) on animals. Much of the diet consisted of mol- 

 luscs (e.g., mussels, cockles, clams, snails, scallops) and crustaceans (e.g., 

 amphipods, crabs, barnacles, crayfish, shrimp). Fishes and their eggs, insects, 

 frogs and tadpoles, echinoderras (e.g., sand dollars, sea urchins, starfish, 

 brittle stars) and annelids are also eaten. Inland, freshwater clams are pre- 

 ferred. Vegetable foods eaten in North America are largely pondweeds , includ- 

 ing Zostera , Potamogeton , and Ruppia , as well as various algae. 



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