OF ARTS AND SCIENCES. 165 



previously noted, was again singing with all its springtime vig- 

 or about the camp. I also heard a few singing in early Sep- 

 tember, 1 90 1, while on a trip over this range. These I take to 

 be the resident birds still on their breeding grounds, as I have 

 never observed the migrants at low altitudes singing in fall. 

 Under the head of Migration, I have detailed some observations 

 on the interesting movements of the Black-poll Warblers, and 

 it may be again remarked that they appear to migrate along 

 the mountain tops in fall, keeping generally above 2,000 feet or 

 so, and uncommonly appearing in the valley bottoms at this 

 season among the White Mountains, though after the central 

 parts of the state are reached, they flood the low country as we 

 are accustomed to see in Massachusetts. In the lower part of 

 the state, the spring migration is over by early June, and the 

 fall migrants again appear in late August or early September. 

 Dates : May 8 to October 10. 



219. Denclroica blackburniae (Gmel.). Blackburn- 

 ian Warbler. 



A rather common summer resident of the sub-Canadian 

 woods, especially those of mixed hemlock and deciduous growth. 

 In the southern part of the state, Dr. W. H. Fox writes that it 

 breeds at Hollis, and it is well known to nest about Mt. Monad- 

 nock and northward along the ridge forming the eastern rim of 

 the Connecticut valley basin. In the White Mountain region, 

 it is common in the white pine and spruce woods up to about 

 3,000 feet, but above this level only a few scattering pairs occur. 

 Dr. A. P. Chadbourne ('87) records seeing a single bird at 

 3,800 feet on Mt. Washington on July 8, 1886. 



Dates : May 4 to September 10. 



220. Dendroica virens (Gmel.). Black-throated 

 Green Warbler. 



A very common spring and fall migrant and a common sum- 

 mer resident, breeding most plentifully in the pine and spruce 

 woods of the sub-Canadian area. In such growths, it is very 

 common in the White Mountains up to about 2,000 feet. A 

 few pairs penetrate still farther up the mountain sides into the 



