314 APPENDIX C. — BIRDS. 



BIEDS, 



By spencer F. BAIRD. 



1. BuTEO BOREALis, Bp. — Red-tailed Hawk. 



FaUo borealis, Wils. VI. 72, pi. 52.— Aud. Biog. I. 265, pi. 51. 



Salt Lake. Found by Gambel in California. 



2. AcciPiTER Fuscus, Bp. — Sharp-shinned Hawk. 



Falco velox, Wils. Vll. 110, pi. 45, fig. 1 (young female). 

 Falco pennsylv aniens, Wils. VI. 13, pi. 16, fig. 1 (adult male). 

 Falco fuscus, Aud. Biog. IV. 522, pi. 374. 



Salt Lake. 



3. Athene hypugaea, Cassin. — Burrowing Owl. 



Strix hypugcea, Bp. Am. Orn. I. 72, pi. 7. 



Striz cunicularia, Aud. Biog. V. 264, pi. 432, f. 2. 



Athene socialis, Gambel, Pr. A. N. S. III. 47. 



Abundant in the valley of Salt Lake and on the plains east 

 and west of the mountains. 



4. SiALiA macroptera, Baird. — Long-winged Bluebird, 



Male.— Salt Lake City, March 18, 1850. 



A specimen of Sialia was procured by Captain Stansbury, 

 which, at first sight, was referred to S. arctica of Swainson. 

 On comparing it with others from Fort Union, the differences 

 were found to be sufficiently great to constitute a distinct species. 

 The Fort Union specimen was clearly referable to S. arctica of 

 Swainson shot at Fort Franklin, Great Bear Lake, so that it be- 

 comes necessary to impose a new name upon the one from Utah. 

 Not having at hand specimens from the Pacific coast, it is im- 

 possible to say to which species the birds described by Audubon 

 as S. arctica belong, (probably arctica.) 



The principal difference between the two allied species is to be 

 found in the longer wings, and much smaller and weaker claws, 

 with rather longer toes, of the aS'. macrojptera^ as will be sufficiently 



