THE NtiSrS AND EGGS OF WAEBLING GKEENLETS 505 



crease in numbers until they are as abundant in the towns 

 as our own variety has long since become. They are already 

 numerous in all suitable situations, where their periods of mi- 

 gration and areas of distribution in the breeding season corre- 

 spond perfectly with those of the typical Eastern gilvus. Such 

 are my own observations as far as they go, and we have many 

 others, unnecessary to cite, to the same effect. 



Nor is there any appreciable distinction between the nests of 

 the two varieties or between their eggs. We know how much 

 alike the Vireos all are in these respects, and it would be sur- 

 prising if there were any difference between such closely- 

 related — in fact scarcely separable — varieties as the Warbling 

 and Swainson's Greenlets. Audubon has left us an account of 

 their nest-building, in which he describes with great particu- 

 larity the actions of a pair whom he watched for several days 

 whilst they were busied in the construction of their pretty pen- 

 sile fabrics. The nest is hung in a forked twig, and is peculiar, 

 in comparison with that of other Vireos, neither in this respect, 

 nor in materials nor workmanship; but it is commonly placed 

 higher up, sometimes fifty or a hundred feet from the ground, 

 right under the canopy of foliage of such large trees as the 

 elms, maples, and poplars, where it may sway in the breeze, 

 but is secure against ordinary accidents of the weather, and 

 remote from most enemies, the inevitable Cowbird alone ex- 

 cepted. Such high building, however, is not invariable, for Mr. 

 Ridgway speaks of several nests which he took in Utah, which 

 were built in aspens only about four feet from the ground. In 

 form, the nest is quite deeply cupped, with a somewhat con- 

 tracted brim, for the still greater safety of its precious freight, 

 firmly secured to its slender support, and with closely matted 

 walls. The eggs are usually four or five in number, pure white, 

 oftenest with the reddish- brown spots or even blotches, which 

 are the rule in this genus, but sometimes immaculate ; they are 

 nearly or quite three-fourths of an inch long, by a trifle over 

 half an inch broad, and of the ordinary shape. 



The Blue-headed Ctreenlet 



Vlreo solitarias 



Musclcapa soUtarla, Wite. " AO. IL 1810, 43, pL 17, f. 6 ".—Steph. Shaw's Gen. ZooL x. 1817, 



349.— £p. Journ. Phila. Acad. iv. 1824, 174. 

 Vlreo solitarius, Viettl. " N. D. d'H. N. xi. 1817, — '.—Bp. Journ. PhiltL Acad. iv. 1824, 175.— 



Bp. Ann. Lye. N. T. ii. 1826, ^0.—Aud. OB. i. 1831, 147, pi. W.—Nutt. Man. i. 1832, 305.— 



OrniJi. Oormm. Journ. Pljila. Acad. viL 1837, 193 ("Columbia River").- Up. CGL. 



1838, in.— Towns. Journ. Phila^ Acad. viii. 1839, ISi.—Aud. Syn. 1839, 160.— ^ud. BA. 



iv. 1842, 144, pi. 239.— Gir. BLI. 1844, im.—Qamh. Pr. Pliila. Acad. 1847, 159 (Call- 



