152 LAND-BIRDS AND GAME-BIRDS 
not gregarious, but are extremely affectionate toward one an- 
other, and peaceable in their relations to other birds. They 
are very musical, and warble cheerfully, energetically, and often 
very sweetly. They build small, cup-shaped, pensile nests, 
which are rarely softly lined. The eggs are four or five, and 
pure white, with a few small spots near the larger end, of some 
shade of brown. 
Our species have been divided into several subgenera, but I 
have here followed Dr. Coues in uniting them under one genus. 
I. VIREO 
(A) sorrrarius. Solitary Vireo. Blue-headed Vireo. 
(Rather rare in Massachusetts, especially as a summer-resi- 
dent.) 
(a). About 52 inches long. Olive-green above, and white 
beneath. Head, bluish-ash; eye-ring, and line to bill, white. 
Sides olive-shaded. Wing- and tail-feathers white-edged, and 
wings white-barred. 
(b). The nest of the Solitary Vireo is open and pensile, like 
those of the other vireos. It is placed, never far from the 
ground, in the fork of a horizontal branch, always in the woods, 
and sometimes in swampy ones. It is usually larger, and more 
loosely constructed of somewhat finer materials, than that of 
the “Red-eye” (c). One, now lying before me, is composed 
chiefly of thin strips of pliable bark, is lined with fine grasses 
and a very few roots, and is somewhat ornamented outwardly 
with plant-down, lichens, and bits of dead leaves. Audubon 
speaks of others as being lined with hairs, which I have never 
known to be the case. In Massachusetts, three or four eggs 
are laid in the first week in June. They average *77 X 58 of 
an inch, and are pure white, with a very few minute and gener- 
ally reddish-brown spots principally at the larger end. 
(c). The Solitary Vireos are less well known than our other 
vireos, since they are more given to solitude, and never fre- 
quent the immediate neighborhood of man. In this respect 
they resemble the White-eyed Vireos, but are much less com- 
mon here, for in the breeding-season the southern limit of 
