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THE BLUE-GREEN WARBLER. 



Syl via rarj, Wils. 



PLATE XLIX. Male. 



The Blue-green Warbler so resembles the young of the Azure War- 

 bler, that were not the form of its bill, and some of its habits, consider- 

 ably different, I should be tempted to consider it a mere variety of that 

 bird. It is equally rare in the Middle Districts, where I have shot only 

 a few, and these in the dark recesses of the G reat Pine Swamp. 



On its passage through the States, it is found in Louisiana, where it 

 appears in the beginning of April. This lateness of its arrival indicates 

 its coming from a great distance, most of the other species appearing 

 several weeks earlier. They seem to disperse soon after, as on their first 

 appearance several may be procured in one day, as well as during their 

 equally short stay in autumn, when, again, I have shot six or seven from 

 a single tree, on which they appeared as busily engaged as if so many Tit- 

 mice. I have met with them singly and far apart in Kentucky, in Ohio, 

 upon the Missouri, and along Lake Erie, but I have never found their nest. 

 In spring it has a soft and mellow song, which is not heard beyond 

 the distance of a few paces. It is performed at intervals between the 

 times at which the bird secures an insect, which it does with great ex- 

 pertness, either on wing, or amongst the leaves of the trees and bushes. 

 The tops of trees, however, appear to please them best, the reverse being 

 the case with the Azure Warbler. 



The Blue-green Warbler has a peculiar cunning manner of leaning 

 downwards to view a person, or while searching for an insect, and which 

 is very different from that of any other bird, although I am unable to 

 describe it. While thus leaning, it moves its head sidewise so very 

 slowly that the motion is hardly perceptible, unless much attention is 

 paid to it. After this, it either starts off and flies to some distance from 

 the observer, or darts towards the prey that had attracted its notice. 

 While catching an insect on the wing, it produces a shght cUcking sound 

 with its bill, and in this respect approaches the Vireos. Like some of 

 them also, it descends from the highest tops of the trees to low bushes, and 

 eats small berries, particularly towards autumn, when insects begin to fail. 

 Its flight is performed in zigzag lines of a few yards, as if it were 



