184 UNIVERSITY OF COLORADO STUDIES 



Suborder Cepphi, Loons, etc. 



Family GAV1IDAE, The Loons 

 Gavia immer, Loon (7) 



Migrant; apparently rare; the records are from the Plains. One was taken 

 by L. C. Bragg, 1901 ; one seen by Henderson, May 7, 1905 ; there was a specimen 

 in possession of F. M. Manshardt taken March 10, 1908; and one was seen by the 

 writer on May 10 and n, 1912. 



Order LONGIPENNES, Long- winged Swimmers 



Family STERCORARIIDAE, The Jaegers, etc. 

 Stercorarius parasiticus, Parasitic Jaeger (37) 



There was one specimen in Mrs. Maxwell's collection taken near Boulder in 

 December some time previous to r874. Sclater records only three specimens for 

 Colorado. 



Family LARIDAE, The Gulls and Terns 

 Rissa tridadyla tridaclyla, Kittiwake (40) 



There was one specimen in Mrs. Maxwell's collection taken in Boulder County 

 in December; it is the only record for Colorado. 



Larus delawarensis, Ring-billed Gull (54) 



Migrant; probably rather common on the lakes of the Plains. Hunters 

 report it occasionally, and it is common at the Barr Lakes. Definite dates for 

 the county are May, 1902, and October 31, 1909 (specimens in the University col- 

 lection), and September 22, 1912 (3 birds seen by the writer). Gale listed it as a 

 "summer visitant" for "Boulder Valley." 



Xema sabini, Sabine's Gull (62) 



One specimen in the University collection was secured by James Cowie on 

 September 15, 1907, out of a flock of six. Recorded from the county by Cooke; 

 apparently rare in Colorado. 



Sterna forsteri, Forster's Tern (69) 



Migrant; probably occurs regularly in limited numbers on the lakes of the 

 Plains, as it is common at the Barr Lakes, where it breeds. Seen in the county 

 May 12 and September 15, 191 2, by the writer. 



Hydrochelidon nigra surinamensis, Black Tern (77) 



Migrant; common though not numerous about the lakes on the Plains. A 

 specimen in the University collection was taken in 1904. Noted by the writer in 

 the fall only, between August 6 and September 15. It is a common breeding bird 

 at the Barr Lakes. 



