DISTRIBUTION OF THE BLUE-HEADED GREENLET 507 



from nostrils to and around (not behind) the eye, and dusky loral space. 

 Below pure white, the sides strongly washed with yellowish, with some 

 olive shading, the under wing- and tail-coverts quite yellowish. Quills and 

 tail-feathers blackish, strongly edged with white or with the color of the 

 back, or both, and the tips of the greater and middle coverts the same, 

 forming two conspicuous wing-bars. Bill blackish-plumbeous, not always 

 paler below; feet plumbeous; iris brown. Length about 5; extent, 8^; 

 wing, 2f ; tail, 2 ; bill about $ long, nearly half as deep at the base. 



Immature specimens are rather brighter-colored. At any season there 

 may be rather less contrast than as above indicated between the color of the 

 back and head, either owing to a slight ashy dorsal wash as in spring ex- 

 amples, or to an olivaceous shading of the head in others. But there can 

 be no difficulty in recognizing the species by the characters above given. 



THE movements of the Blue-headed Vireo are somewhat 

 difficult to trace with entire precision, and the mode of 

 its dispersion in this country has been much in question. The 

 bird appears to be of rather irregular or uncertain distribution, 

 quite common in some districts, and rare in others which seem 

 equally suited to its requirements. Its history has never yet 

 been fully presented, and it is only within two or three years 

 that some important advices, before wanting, have come to 

 hand, with respect more particularly to its occurrence in the 

 Colorado Valley, where it was long supposed to be absent, 

 though known to occur both in Texas and California. With 

 the materials now at our disposition, however, the history of 

 the species may be attempted with some confidence. 



It was first described in 1810 by Wilson, who figured a speci- 

 men taken in October near Philadelphia, and saw altogether 

 no more than three individuals, though he also inspected a 

 drawing of one made in Georgia, where the bird was considered 

 to be rare. He simply remarks that it is a rare species and a 

 silent solitary bird, giving no further indication of its habits, 

 but surmising that it may have its headquarters in some por- 

 tion of the country unknown to him. Nothing whatever was 

 added to this meagre account until Audubon in 1831 gave some 

 further particulars, though in the mean while various compilers 

 and " systematizers " treated of the species. The short notice 

 in NuttalPs 'Manual 7 is entirely drawn from these two sources. 

 Audubon's account, though extended and circumstantial, and 

 including an unmistakable description of the bird, is to be taken 

 neverthelesss with some allowance for confusion of memory or 

 other source of error. He represents the bird as an abundant 

 inhabitant of the cane-brakes of Louisiana, in which he says 

 it breeds. But, as both Mr. Gentry and Dr. Brewer have 



