Part 21

54. =Ring-billed gull.= LARUS DELAWARENSIS. Not uncommon summer resident; common in migration; breeds as high as 7,500 feet; range, whole of North America.

58. =Laughing gull.= LARUS ATRICILLA. Bird of South Atlantic and Gulf States; once accidental in Colorado.

59. =Franklin's gull.= LARUS FRANKLINII. Rare migrant; range, interior of North America.

60. =Bonaparte's gull.= LARUS PHILADELPHIA. Rare migrant; not uncommon in a few localities; range, whole of North America.

62. =Sabine's gull.= XEMA SABINII. Rare winter visitant; breeds in the arctic regions.

69. =Forster's tern.= STERNA FORSTERI. Rare summer resident; common migrant; habitat, temperate North America.

71. =Arctic tern.= STERNA PARADISÆA. Very rare migrant; but two records; breeding habitat, circumpolar regions.

77. =Black tern.= HYDROCHELIDON NIGRA SURINAMENSIS. Common summer resident; both sides of range; habitat, temperate North America; in winter south as far as Brazil and Chili.

120. =Double-crested cormorant.= PHALACROCORAX DILOPHUS. Perhaps breeds in Colorado, as it breeds abundantly in Utah; all present records from eastern foothills.

125. =American white pelican.= PELECANUS ERYTHRORHYNCHOS. Once a common migrant; a few remained to breed; now rare; still noted on both sides of the range.

129. =American merganser.= MERGANSER AMERICANUS. Resident; common migrant and winter sojourner; a few breed in mountains and parks; generally distributed in North America.

130. =Red-breasted merganser.= MERGANSER SERRATOR. Rare winter sojourner; common migrant; breeds far north.

131. =Hooded merganser.= LOPHODYTES CUCULLATUS. Rare resident both summer and winter; breeds in eastern part and in the mountains; general range, North America.

132. =Mallard.= ANAS BOSCHAS. Very common in migration; common in winter; breeds below 9,000 feet, on plains as well as in mountains; general range, whole northern hemisphere.

134a. =Mottled duck.= ANAS FULVIGULA MACULOSA. Rare migrant; an eastern species, sometimes wandering west to plains.

135. =Gadwall.= CHAULELASMUS STREPERUS. Summer resident; common in migration; breeds on plains; also in sloughs and small lakes at an elevation of 11,000 feet in southern part of State; breeds abundantly at San Luis Lakes.

137. =Baldpate.= MARECA AMERICANA. Summer resident; breeds from plains to 8,000 feet.

139. =Green-winged teal.= NETTION CAROLINENSIS. Common summer resident; abundant in migration; a few breed on the plains; more in mountains and upper parks.

140. =Blue-winged teal.= QUERQUEDULA DISCORS. Same records as preceding.

141. =Cinnamon teal.= QUERQUEDULA CYANOPTERA. Common summer resident; breeds both east and west of the range; a western species; in winter south to Chili, Argentina, and Falkland Islands; sometimes strays east as far as Illinois and Louisiana.

142. =Shoveller.= SPATULA CLYPEATA. Summer resident; abundant in migration; breeds in suitable localities, but prefers mountain parks 8,000 feet in altitude; breeds throughout its range, which is the whole of North America.

143. =Pintail=. DAFILA ACUTA. Rare summer and winter resident; common migrant; mostly breeds in the North.

144. =Wood duck.= AIX SPONSA. Rare summer resident.

146. =Redhead.= AYTHYA AMERICANA. Common migrant; breeds far north; migrates early in spring.

147. =Canvas-back.= AYTHYA VALLISNERIA. Migrant; not common; breeds far north.

148. =Scaup duck.= AYTHYA MARILA. Rare migrant; both sides of the range; breeds far north.

149. =Lesser scaup duck.= AYTHYA AFFINIS. Migrant; not common; a little more common than preceding.

150. =Ring-necked duck.= AYTHYA COLLARIS. Rare migrant, though common in Kansas; breeds in far North.