290 Field Museum of Natural History — Zoology, Vol. IX. 



1884, one was seen by Dr. P. R. Hoy, at Racine, Wisconsin." (Bird 

 Migr. Miss. Valley, 1888, p. 55.) 



Genus LARUS Linn. 

 13. Larus hyperboreus Gunn. 

 Glaucous Gull. 



Larus glauciis Briinn., A. O. U. Check List, 1895, p. 16. 



Distr.: Arctic regions, south in winter to New England, New York, 

 and the Great Lakes. 



Adult in summer: General plumage, except back and wings, white; 

 back, pale pearl gray; wings, pearl gray; primaries, pearl gray, shad- 

 ing into white on the edges of the inner webs and at the tips. 



Adult in winter: Siinilar, but having the head and neck streaked 

 with pale gray. 



Immature birds have the upper plumage pale gray or whitish, 

 heavily marked and barred with pale brown and gray; under parts 

 ash gray or grayish white, often marked with buff. 



Length, about 27 to 32; wing, 17 to 18.70; bill, about 2.50. 



The Glaucous Gull is a rare winter visitant on Lake Michigan. 

 Both this and the Iceland Gull have the primaries white, pearl white, 

 or pale ash color, never marked with dark brown or black. 



"A rather rare winter visitant to Lake Michigan." (Nelson.) 

 "Occasionally visits Lake Michigan in winter." (Ridgway.) Mr. 

 Frank M. Woodruff states that he killed a bird of this species on Lake 

 Michigan near Millers, Indiana, on August 8, 1897, describing it as "in 

 the pure white plumage of the young of the second year." (The Auk, 

 Vol., XV, 1898, p. 61. ) "In the Milwaukee Public Museum are three 

 specimens procured at Milwaukee, January 8, 12, and 14, 1895." 

 (Kumlien and Hollister, Birds of Wisconsin, 1903, p. 9.) 



14. Larus leucopterus Faber. 



Iceland Gull. 



Distr.: Arctic regions, south in winter to New England and the 

 Great Lakes, and occasionally further south. 

 Adult: Similar to Glaucous Gull, but smaller. 

 Length, 24 to 26; wing, 15 to 16.60; bill, 1.60 to 1.75. 

 Apparently a rare winter visitant to Lake Michigan. 

 "Rare." (A. J. Cook, Birds of Michigan.) " An occasional winter 



