OF ARTS AND SCIENCES. 183 



quiet as the rising sun lit up more and more of the far side of the 

 notch, until finally by 8 : 30, its rays shone full into the cleft of 

 the mountain, and only a single bird was still calling from a 

 spot yet shaded by a protruding shoulder. 

 Dates : May 25 through September. 



251. Hylocichla ustulata swainsonii (Cab.). OUVE- 

 BACKED THRUSH. 



A rather common spring and fall migrant and summer resi- 

 dent. During the breeding season it is commonest in the damp, 

 cool undergrowth of evergreen and young second growth along 

 brooks, or wood-swamps of the sub-Canadian regions, where it 

 is found with the Winter Wren and Canada Warbler. It is 

 essentially a bird of the cool, moist thickets, and is found in 

 the White Mountains up to 4,500 feet. Above 3,000 feet or 

 thereabouts, on entering the upper Canadian zone, its numbers 

 become slightly less, and the few birds occurring above 4,000 

 feet are confined rather closely to the stream beds. This dis- 

 tribution, which has also been noted by Dr. A. P. Chadbourne 

 ('87), I was interested to observe among other places in the 

 mountains, while on a trip with Mr. V. D. Lowe in June, 1900, 

 through the Great Gulf of Mt. Washington. We camped at 

 Spaulding's Lake, a tiny sheet of water at the foot of the head 

 wall and at an elevation of about 4,500 feet. All about was a 

 thick growth of scrubby balsams and large alder bushes. Bick- 

 nell's Thrushes inhabited this growth on all sides well up onto 

 the walls of the gulf, and at all hours of the day were heard 

 calling. There was noted here but a single Olive-backed 

 Thrush, this being a fine male, who sang persistently from 3 

 o'clock in the morning until our departure, a few hours later, 

 secured from view the while by the thick balsam scrub at the 

 foot of the lake. A little farther down the brook, a second bird 

 was heard singing on that morning of June 2ist, but it was evi- 

 dent that these were the extreme outposts which at these upper 

 levels had invaded the Bicknell's Thrushes' territory. On the 

 lower mountain tops, Olive-backed Thrushes are not uncommon 

 in dry spruce thickets with the Hermits. South of the White 



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