44 
DUCKS, GEESE, AND SWANS 
Distribution. — Tropical and subtropical seas, chiefly north of the equa¬ 
tor ; north regularly to Florida, Texas, and California, and casually to 
Wisconsin and Nova Scotia. 
Nest. — Made of sticks, placed in the tops of bushes or low trees. 
ORDER ANSERES: LAMELLIROSTRAL 
SWIMMERS. 
FAMILY ANATID2E: DUCKS, GEESE, AND SWANS. 
KEY TO GENERA. 
1. Tarsus shorter than middle toe without claw. 
Fig. 61. 
Fig. 62. 
2. Neck as long as or longer than body . . Olor, p. 70. 
2'. Neck shorter than body. 
3. Lower mandible without trace of lamellse along sides, 
edges of mandibles strongly toothed or serrate. 
4. Tooth-like serrations of mandibles sharp and 
strongly inclined backward 
Merganser, p. 45. 
4'. Tooth-like serrations of mandibles blunt and not 
distinctly inclined backward 
Lophodytes, p. 47. 
3'. Lower mandible with a distinct series of lamelke along 
side as well as cutting edge. 
4. Lower part of tarsus with small hexagonal plates 
and no transverse scutellae in front. 
Dendrocygna, p. 69. 
4'. Lower part of tarsus with a row of transverse scu- 
tellse across the front. 
5. Tail without upper coverts, the base of the stiff 
feathers scarcely concealed. 
6. Tail feathers 18 . . . Erismatura, p. 64. 
6'. Tail feathers 20 . . . Nomonyx, p. 65. 
5 . Tail with base well concealed by upper coverts. 
6. Hind toe without a flattened membraneous 
lobe. 
7. Bill long and much wider near end than 
toward base .... Spatula, p. 54. 
7 . Bill not much wider near end than at base. 
8. Tail feathers wide and rounded at end. 
, . mx, p. oo. 
8 . Tail feathers narrow and pointed at tips. 
9. Tail graduated more than a third of its 
total length. 
10. Tail feathers 14 . Mareca, p. 49. 
10'. Tail feathers 16. 
11. Bill longer than middle toe with¬ 
out claw . . . Dafila, p. 54. 
11. Bill shorter than middle toe with¬ 
out claw 
. Chaulelasmus, p. 49. 
9 . Tail graduated less than a third of its 
total length. 
