CHECK-LIST OF COLORADO BIRDS 309 



40. Kittiwake. RISSA TRIDACTYLA. Rare or accidental 

 in winter. 



49. Western gull. LARUS OCCIDENTALS. Pacific Coast 

 bird ; accidental in Colorado ; only one record. 



5 la. American herring gull. LARUS ARGENTATUS SMITH- 

 SONIANUS. Rare migrant; range, the whole of North 

 America. 



53. California gull. LARUS CALIFORNICUS. Western 

 species; breeds abundantly in Utah; only three records 

 for Colorado. 



54. Ring-billed gull. LARUS DELAWARENSIS. Not un- 

 common 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 mi- 

 grant ; not uncommon in a few localities ; range, whole of 

 North America. 



62. Sabine's gull. XEMA SABINII. Rare winter visi- 

 tant; breeds in the arctic regions. 



69. Forster's tern. STERNA FORSTERI. Rare summer 

 resident; common migrant; habitat, temperate North 

 America. 



71. Arc tic tern. STERNA PARADIS^A. 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. 



