Il6 BIRDS OF COLORADO. 



limit in southern Colorado. F. M. Drew says that it is common 

 on the tributaries of the San Juan River, breeding in the pines 

 from 6,000 to 7,000 feet. (B. N. O. C. VI. 1881, 85.) In La 

 Plata County, Chas. F. Morrison found them not common and 

 took eggs in May at 8,500 feet. A most surprising occurrence 

 was the appearance of a small flock of these birds in the spring 

 of 1889 at Loveland, where they were seen by Prof. Wm. Osburn 

 and one secured April 25. At the request of the present writer, 

 the specimen has been lately re-examined and there is no doubt 

 of the identification. 



665. Dendroica nigrescens. Black-throated Gray War- 

 bler. 



Summer resident ; rare. A western species coming north 

 to north central Colorado and east to the base of the foothills, 

 but never common. Arrives early in May. Has been taken at 

 Silverton, 9,500 feet,' May 30, and at Idaho Springs, 7,800 feet. 

 May 23. Its breeding range in the State has not been satisfac- 

 torily determined. 



668. Dendroica townsendi. Townsend's Warbler. 



Summer resident; not uncommon. A western species 

 coming east regularly to the base of the foothills and a few 

 miles out on the plains. The most eastern record is that of 

 Capt. P. M. Thorne at Fort LyOn, one only seen. May 26, 1883. 

 Rare on the plains at any time and then only as a migrant, 

 passing north the latter part of May and returning in Septem- 

 ber. In the mountains it is rather common during the fall mi- 

 gration from 7,500 to 10,000 feet. Rather rare in summer, 

 breeding from 5,500 to 8,000 feet in western Colorado. No 

 record of its breeding east of the Rocky Mountains. 



674. Seiurus aurocapillus. Oven-bird. 



Summer visitant; rare or accidental. The only fully au- 

 thentic record for Colorado is the single specimen taken by Dr. 

 C. Wernigk at Denver in June, 1862. It will probably yet be 

 found as a rare visitant to northeastern Colorado, since it is not 

 uncommon a short distance from the State line. 



675a. Seiurus noveboracensis notabilis. Grinnell's 

 Water"Thrush. 



Migratory; rare. Recorded from Denver, Boulder, Neder- 

 land, Ivoveland and Fort Lyon, i. e., from the plains to 8,000 

 feet. Passes through Colorado the latter part of May. Not 

 known to breed. 



680. Geothlypis macgillivrayi. Macgillivray's Warbler. 



Summer resident ; common. Arrives early in May and 



breeds from the base of the foothills to 9,000 feet. Laying begins 



