42 DIVERS—COLD-WEATHER DIVERS. 
GENUS MERGANSER. 
MERGANSER Americanus — AMERICAN MERGANSER, 
SHELLDRAKE, FisHpuck.—Habitat.—Both coasts and 
interior of North America at large; south to Gulf of 
Mexico and West India Islands. When the first 
glimpse of water can be seen in the shape of narrow 
channels upon the large waterways above the frost 
line, the fishduck or shelldrake, as he is locally called, 
puts in an appearance, and fights his way northward 
ahead of any other bird. The second and third issues 
follow, a few days existing between each flight. They 
seem to enjoy frozen, rotten fish with the same gusto 
as fresh, picking them out of the floating ice. During 
the fall flight they pass over at night, always following 
the large streams and rivers, coming down late in the 
season, for few breed on this side the boundary line. 
Their feeding grounds are on large streams, and they 
display a great deal of sagacity when feeding in flocks. 
Forming a half-moon, keeping well together, after the 
appearance of the corks of a seine, they slowly drive, 
by repeated diving, the fish to a shallow place or bank, 
where, still keeping the half circle, they dive and 
catch the fishes as they reach the shallows; having 
once got the fish into shallow water, where they ripple 
the surface, the ducks rush in and rapidly devour 
fishes of a large size. Their roosting grounds are in 
lakes and rivers, preferring open water. Their play- 
ing grounds are in open water, floating about, gener- 
ally after a heavy feed. 
Their clutch is from eight to ten yellowish-white 
eggs. Length 26.00 to 27.00; wing 11.00; tarsus 1.90; 
extent 36.00; middle toe 2.20. 
