BLACKBURNIAN WARBLER. 233 



The Blackburnian Warbler is one of the rarest and most 

 beautiful species of the genus, which from the ist to the 15 th 

 of May, or sometimes later, pays a transient visit to the Middle 

 and Northern States, on its way to its remote boreal place of 

 retirement for the breeding season. It is still more rarely seen 

 in the autumn, about the month of September, in its passage 

 to tropical America, where it winters, as may be presumed, from 

 its occurrence late in autumn about Vera Cruz, according to 

 Mr. Bullock. It is an exceedingly nimble insect-hunter, keep- 

 ing towards the tops of trees, scarcely uttering even an audible 

 chirp, and at this season no song as far as is yet known. 



On the Magdalene Islands in the Gulf of St. Lawrence, in 

 June, Audubon remarks that he heard the song of this beauti- 

 ful warbler, consisting of five or six loud notes, which it uttered 

 from the branches of a fir-tree while engaged in quest of its 

 prey. The nest found in Nova Scotia was made externally of 

 coarse materials and lined with silky fibres and delicate strips 

 of bark, over which lay a thick bed of feathers and horse- hair. 

 It was found in a small fork of a tree, 5 or 6 feet from the 

 ground, near a brook. Dr. Brewer also found a nest of this 

 species in Massachusetts. 



The very rare adult of the Hemlock Warbler was found by 

 Wilson in the Great Pine Swamp in Pennsylvania, and ap- 

 peared to take up its residence in the dark hemlock-trees of 

 that desolate region. It was very lively and active, climbing 

 among the branches and hanging from the twigs like a Tit- 

 mouse. It darted after flies to a considerable distance, and 

 beginning with the lower branches, hunted with regularity up- 

 wards to the summit of the tree, and in this way it proceeded 

 very industriously to forage through the forest till satisfied. At 

 intervals it stopped an instant to warble out a few low and 

 sweet notes, probably for the recognition or company of its 

 mate, which the discoverer, however, did not see. 



The nest of this species, according to Audubon, who discov- 

 ered it in the Great Pine Swamp, was made in a hemlock or 



