grass, and blue-^rass split into fine shreds. In towns and near farm-houses, where the majority of nests 

 are built, pieces^f string and thread may be used in the foundation, together with various other sub- 

 stances too numerous and inconstant to mention. But wherever built, and of whatever materials, the 

 structure generally has a neat and compact appearance. The greatest external diameter of the nest, which 

 is about midway between the rim and bottom, varies, in different specimens, from two and one-half to 

 three inches ; external depth, from one and seven-eighths to two and one-fourth inches. The cavity at 

 the rim is very uniform in diameter, rarely varying more than one-eighth from two inches. Internal 

 depth varies from one and one-fourth to one and five-eighths inches; general average, one and one-half 

 inches. Usually the diameter of the cavity is a little greater half an inch below than at the rim. 



EGGS: 



The number of eggs in a full set varies from three to five. They are pure white, with from ten to 

 twenty spots, and as many speckles of chocolate-brown of different shades, confined chiefly to the base. 

 Some specimens have but one or two minute dots upon them; others sometimes have a blotch of light 

 brown; and still others are said to be immaculate. In long-diameter they measure from .70 to .78; in 

 short-diameter they measure from .51 to .60. Average of twenty-one specimens, .73 x .57. 



DIFFERENTIAL POINTS: 



While no rule can be given which will differentiate with certainty the nest and eggs of this species 

 from that of the Red-eyed Vireo, yet it may be stated, as a general fact, that the nest is more compact 

 and situated higher in the trees, and the eggs smaller and less spotted. According to Dr. Brewer, the 

 eggs are less spotted than those of any of the other Vireos. A careful reference to the materials and 

 dimensions, as well as locality and position, will usually determine the species. 



REMAEKS : 



Plate XXIII, fig. 1, illustrates a nest taken the twentieth of May, 1877, from a silver-poplar, 

 standing beside a country road. It was near the extremity of a limb, about thirty feet from the ground. 

 It contained four fresh eggs. The foundation of this nest is composed of flaxen fibres and grasses ; the 

 superstructui'e, of rfibres, gi'asses, bits of decayed weeds, and a downy substance from the poplar ; the 

 lining is made entirely of roller-grass. The external diameter is nearly three inches ; from the lowest 

 part of the rim to the bottom is about two inches; the cavity at the rim, two inches. It seemed unnec- 

 essary to figure more than two eggs, as they differ from each other so slightly ; the two represented 

 show the common sizes and markings. 



I have never noticed the male or female display any unusual amount of combativeness when the 

 nest is disturbed; but Mr. Charles Dury, of Avondale, has Avritten to me as follows: ^Tor years the 

 Warbling Vireos have nested in the silver-poplars, near the house. They are very energetic and happy 

 little birds, and very courageous and solicitous for the safety of their nests, darting at any intruder with 

 such violence as to quickly clear the pi'emises. When the female is sitting, should a Grackle or a Robin 

 come near, she will dart at it and sound the war-cry. Then instantly the male will join her, and the 

 trespasser will be quickly routed. From the vicious way they assert their rights, an old lady here calls 

 them the ' Warbling Viragos.' " 



The song of the Warbling Vireo may be heard in the neighborhood of the nest almost any hour 

 of the day. The male, as he moves from branch to branch, peering now for an insect on a leaf, now on 

 a twig, gives forth a sweet, flute-like melody, in striking contrast to the rattle of wagons, clatter of feet, 

 and hum of busy voices in the street beneath. While, in the country, where all is quiet, the music 

 charms the listener, and holds him a willing captive, as he endeavors to translate into English the words 

 set to the music of the busy little bird. 



94 



