272 Brewster, Notes on the Philadelphia Vireq \sM^ 



occurred to me that the notes of the Philadelphia Vireo are closely 

 similar to those of the Red-eye and that I had found the former 

 species in this very same piece of woods in 1879. No sooner 

 had this thought entered my mind, than I began to give critical 

 attention to the voice that continued to come almost unceasingly 

 from somewhere among the upper branches of the aspen. It was 

 exceedingly like that of Vireo olivaceus but pitched in a slightly 

 higher key, while the notes were less varied and separated by 

 decidedly wider intervals. One of them, moreover, was dissimilar 

 in form to anything that the Red-eye habitually utters. As I 

 noted these slight peculiarities it came back to me that they were 

 all characteristic of the song of the Philadelphia Vireo which, by 

 the way, I had last heard in 188 1, and hence did not remember 

 very vividly. All the while I had been momentarily expecting to 

 get a sight at the singer, or, at least, to ascertain his exact posi- 

 tion, for there was not a breath of wind and no bird, however 

 small, could have stirred among the ea,sily agitated leaves of the 

 aspen without betraying his whereabouts. The leisurely, halting 

 song, however, continued to afford the only tangible evidence that 

 a Vireo was concealed somewhere among the dense, deep green 

 foliage. After encircling the tree a dozen times or more, tilting 

 my head upwards until the muscles'of my neck ached intolerably, 

 I lost all patience and deciding that the bird must be sitting quite 

 motionless on some leafy twig — as Vireos will sometimes do for 

 many minutes at a time:, when singing in the heat of the day — I 

 collected a number of stones with the intention of throwing them 

 at random into the denser parts of the tree, hoping thereby to 

 dislodge the sluggish bird. Just as I was about to carry this plan 

 into effect it occurred to me that the males of certain of our New 

 England Vireos are given to singing on the nest while taking their 

 turns at incubating the eggs.^ This reflection caused me to drop 

 the stones and begin looking for a nest instead of a bird. A few 

 moments later I saw, through an opening in the foliage, in the 

 very middle of the tree, scarce ten feet below its topmost twigs 

 and fully thirty feet above the ground, a globular object of a light 



1 1 have never known the Red-eye to do this but it is a common if not 

 regular practice with the Warbling and Solitary Vireos. 



