BIRDS OF COLORADO. II5 



by the middle of May. Breeds from the northern United States 

 northward. Much less common during fall migration. 



656. Dendroica auduboni. Audubon's Warbler. 

 Summer resident; abundant. During the summer this is 



the most common Warbler among the higher mountains. Ar- 

 rives on the plains early in May and in migration is very com- 

 mon at the western edge of the plains and less and less common 

 eastward to western Kansas. Is known on the plains only as a 

 migrant. Extends into the mountains the middle of May and 

 by the last of the month has reached the upper limit of its 

 range. Breeds from 7,500 to 11,000 feet and is most common 

 above 9,000 feet. Laying begins from the last of May in south- 

 western Colorado to the middle of June in the north-central 

 part of the State. The last leaves the plains for the mountains 

 the last week in May. Begins to return in August; during Sep- 

 tember is common in the lower parks and appears on the plains. 

 Leaves the State in October. 



657. Dendroica maculosa. Magnolia Warbler. 

 Migratory ; rare. In migration extends westward to the 



western edge of the plains, where one was taken by Henshaw 

 at Denver May 17, 1873. Capt. P. M. Thorne has also taken 

 one at Fort Lyon May 17, 1884. Breeds in the northern 

 United States and northward. 



658. Dendroica rara. Cerulean Warbler. 



Migratory ; rare. The only Colorado record is the one 

 seen by Henshaw at Denver May 17, 1873. ^" eastern species 

 common in Kansas during migration and rarely breeding in that 

 State. 

 [659. Dendroica pensylvanica. ChesTnuT-sided Warbler. 



One was taken by Mr. Bond at Cheyenne, Wyo., May 23, 1889. (Auk, 

 VI. 1889, 341.) This is only just over the line from Colorado, and the bird, 

 which is a common species a little farther east, may have crossed Colorado or 

 may have passed westward up the Platte River.] 



661. Dendroica striata. Black-poll Warbler. 



Summer resident; rare. An eastern species coming rarely 

 but regularly west to the Rocky Mountains. Occasionally com- 

 mon in migration, both on the plains and at the base of the foot- 

 hills. The only record of breeding in Colorado, and the most 

 southern in the United States, is that of H. D. Minot who found 

 it as a summer resident at Seven Lakes, near Mauitou, at an alti- 

 tude of 11,000 feet. (B. N. O. C. V. 1880, 233.) Reaches 

 Colorado about the middle of May. 



664. Dendroica graciae. Grace's Warbler. 



Summer resident; common in extreme southwestern Colo- 

 rado. A southwestern species reaching its extreme northern 



