grass, and blue-grass split into fine shreds. In towns and near farm-liouses, where the majority of nests 
are built, pieces of 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 arc 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 othei's are said to be immaculate. In long-diameter they measure from .70 to ,7S; 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 Yireo, 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. 
REMARKS : 
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 
superstructure, of fibres, grasses, 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 written to me as follows: “For 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 premises. When the female is sitting, should a Gfrackle 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 
