THE BIRDS OF BOULDER COUNTY 225 



[9. Gavia arctica — Black-throated Loon. 



The former record of this species too doubtful to be retained.] 

 37. Stercorarius parasiticus— Parasitic Jaeger. 



Mrs. Maxwell's December specimen the only Boulder County record. 

 40. Rissa tridactyla — Kittiwake. 



Mrs. Maxwell's December specimen the only Boulder County record. 

 54. Larus delawarensis — Ring-billed Gull. 



Common on the plains in migration. 

 62. Xema sabinii — Sabine Gull. 



Recorded from here by Cooke, and six reported on the plains during migration season 

 by Cowie, one of which he secured for the University. 

 77. Hydrochelidon nigra surinamensis — Black Tern. 



One in University collected by Bragg in 1904, on the plains. 

 125. Pelecanus erythrorhynchos.— American White Pelecan. 



Hunters say it has been occasionally taken on the plains in migration, but have no 

 dates. Doubtless of rare occurence now. 



130. Mergus serrator— Red-breasted Merganser. 

 Reported as a migrant by Rowland. 



131. Lophodytes cucullatus— Hooded Merganser. 

 I have seen but one taken here. 



132. Anas platyrhynchos— Mallard. 



Common on plains in migration and winters here (Cowie). Rockwell found it 

 common west of Lcngmont, December 30-31, 1906, and January 1, 1907. Probably a 

 number of our ducks nest here sparingly, but we cannot assume this. 

 135. Chaulelasmus streperus — Gadwall. 



Common on plains in migration. Rockwell found this and Nos. 137, 140, 141, 142, 

 149, in pairs near Niwot, May 20 and 28, 1904, so they likely nested there. 

 137. Mareca americana— Baldpate. 



Common on plains in migration. See remarks on No. 135. 



139. Nettion carolinensis — Green-winged Teal. 



Common on plains in migration, and some nest here (Cowie). 



140. Querquedula discors— Blue-winged Teal. 



Common on plains in migration, and some nest here (Cowie). See remarks on No. 

 J 35- 



141. Querquedula cyanoptera— Cinnamon Teal. 



Reported on plains in migration by Rowland, Cowie and others. See remarks on No. 

 J 35- 



142. Spatula clypeata — Shoveller. 



Common on plains in migration. See remarks on No. 135. 



143. Dafila acuta— Pintail. 



Common on plains in migration. Hunters reported them in early January, 1909. 



