xlil. 
I. Length over 20 inches. 267. Caspian Tern. 
!l. Length under 16 inches. 
A. Length over 13 inches. 
1. Whcele top of head black. 
a. Bill wholly or mostly black. 
(1). Outer tail feathers pure white. 270. Roseate Tern. 
(2). Inner web of outer tail feather gray. 268. Forster Tern. 
(3). Tail forked for less than 2 inches. 266. Gull-billed Tern. 
b. Bill not black. 
(1). Under parts pure white. 268. Forster Tern. 
(2). Under parts grayish. 269. Common Tern. 
2. Forehead or crown white or gray. 
a. Whole outer tail feather white. 270. Roseate Tern. 
b. Inner web of outer tail feather not white. 268. Forster Tern. 
c. Outer web of outer tail feathers darker than inner269. Common Tern. 
web. 
B. Length under 11 inches. 
1. Under parts white. 271. Least Tern. 
2. Under parts black. 272. Black Tern. 
OrpErR 13. ANSERES. Ducks, Geese, Swans. 
Subfamily 1. MeErcinar. Mergansers. 
To this group belong the “fish ducks’ par excellence. They feed largely upon fish which they 
are enabled to catch with their toothed, hawk-like bills. They dive readily and for considerable 
distances, pursuing the fish under water. They are found about streams and considerable bodies of 
water, some individuals of tne larger species remaining in the state during the winter where open 
waters afford good feeding places. 
I. Length under 18 inches. A conspicuous hood 309. Hooded Merganser. 
II. Length over 21 inches. 
A. Head and throat black. 
1. Under parts white, tinged with salmon. 307. American Merganser. 
2. Breast brownish, heavily streaked with black. 308. Red=breasted Merganser. 
B. Head and sides of neck rufous-brown. 307. American Merganser. 
C. Head and sides of neck grayish-brown, washed with 
rufous. 308. Red-breasted Merganser. 
Subfamily 2. ANAtTINAE. River and Pond Ducks. 
The members of this group may be known at once by the absence of a flap or lobe on the 
hind toe. They feed in shallow water, immersing only part of the body, and hence are called ‘Tip- 
ups’. A feeding flock with heads down and tails in the air looks like the scoring end of a bowl- 
ing alley. They take wing readily from the water. 
I. Length under 17.00 inches. 
\. Under parts chestnut-rufous. 289. Cinnamon Teal. 
B. Under parts not chestnut-rufous. 
1. Lesser wing-coverts blue. 288. Blue=-winged Teal. 
2. Lesser wing-coverts gray. 287. Green-winged Teal. 
Il. Length over 18.co inches. 
\. Belly not conspicuously streaked or spotted. 
rv. Head shining dark green. 281. Mallard. 
2. Center of head white or whitish. 286. Baldpate. 
3. Crown greenish, throat white. 292. Wood Duck. 
4. Crown buffy, throat blackish. 285. Widgeon. 
5. Crown dark olive-brown. 291. Pintail. 
6. Crown finely streaked with black. 
a. Wing-coverts with chestnut. 284. Gadwall. 
b. Wing coverts without chestnut 
(1). Sides barred with black. 291. Pintail. 
(2). Sides plain brown. 286. Baldpate. 
(3). Sides spotted with black. 284. Gadwall. 
B. Belly conspicuously marked, cr chestnut. 
Wing-coverts with white. 
a. Lesser wing-coverts bluish. 290. Shoveller. 
bh. Lesser wing-coverts brownish-gray. 
