WARBLERS. 



101 



Fig. 4. Blue Yellow-tacked Wartler. (i) 



only a few breed, chiefly, probably, in the valleys of the Con- 

 necticut and Nashua rivers. Near Boston they are extremely 

 rare in summer, but are generally common in the second and 

 third weeks of May and September, during their migrations, 

 being, however, sometimes rare, and sometimes extremely 

 abundant. I can in 

 no way, I believe, bet- 

 ter describe their 

 habits than by detail- 

 ing the observations 

 which I made upon 

 them this spring 

 [1875], when they 

 were very numerous 

 in my immediate 

 neighborhood. They 

 came on the eleventh 

 of May, and did not 

 wholly disappear until the twenty-second of that month, after 

 which I saw none, except a few in autumn. They chiefly fre- 

 quented the budding maples, the orchard trees, and the shrubs 

 and bushes which were just pushing forth their young leaves ; 

 sometimes alone, more often in pairs, and less commonly in 

 small parties of three and four. They constantly skipped 

 from twig to twig, much as a Chickadee does, often turning 

 their heads in peculiar attitudes so as to reach the cran- 

 nies behind the buds, and occasionally even hanging head 

 downwards, the better to effect their purposes through their 

 constant activity. They would often take short flights into 

 the air in order to seize some passing insect, and then would 

 immediately return to their former avocations, usually on the 

 same tree. A great charm in the disposition of these pretty 

 and graceful little birds was their entire fearlessness of man, 

 which was so absolute that I many times was within two or 

 three feet of them, even when I was moving. The " Blue 

 Yellow-backs," while migrating, may also be found in the more 

 open and lightly timbered woodland, but seldom among the 

 pines. In their summer homes they inhabit both the ever- 



