WHITE-EYED VIREO 231 



the four extremes measure 21.8 by 14.5, 18.8 by 15.2, 17.1 by 13.5, and 

 17.3 by 12.7 millimeters. 



Incubation. — The duties of incubation are shared by both sexes, 

 and the period has been set at 12 days and at IG days; probably the 

 average period is somewhere between these limits, as it is with other 

 vireos. Aretas A. Saunders (1015), who watched a nest from the 

 time the first egg was laid until the eggs hatched, determined that 

 the period was 15 days. He learned to recognize the sexes by their 

 different behavior and by the song of the male. He says : 



The two birds showed marked individualitj' in the matter of t'enrlessness, the 

 male being much more so than his mate. * * * Frequent visits to tlie nest 

 found sometimes one bird and sometimes the other incubating. The female 

 always left the nest when I was several feet away and scolded me from a dis- 

 tant point in the thicket. The scolding usually brought her mate to the vicinity, 

 and he never failed to take up his position on the eggs immediately unless my 

 hand was actually on the nest. As time went on his courage increased until 

 he would actually peck at my fingers before leaving. * * * [On one] oc- 

 casion the bird pecked vigorously at our fingers, and absolutely refused to 

 oblige us by getting off. We finally had to remove him forcibly. He showed 

 such resistance to tlils that we could do it in no way except to grasp him by 

 the bill and thus lift him off. 



We seem to have no data on the development of the young, nor any 

 information as to their care and feeding, but it seems fair to assume 

 that the male does his share of this work, as he does in nest-building 

 and incubation. Apparently only one brood is raised in a season in 

 the North, but probably at least two in the South. 



Plumages. — The young white-eyed vireo in ju venal plumage is much 

 like the adult, but the upperparts are duller and browner, dull brown- 

 ish olive-green ; the line over the eye and the orbital ring are grayish 

 white or brownish v/hite, instead of yellow ; the underparts are dull 

 grayish white, buffy on the throat, and strongly washed on the sides, 

 flanks, and crissum with j^ellowish or buffy; the iris is grayish or 

 brownish, and does not become white until the next spring. 



Dr. D wight (1900) says that the first winter plumage is acquired 

 "by a complete postjuvenal moult beginning about the middle of 

 August. The juvenal dress is worn much longer than that of the 

 other Vireos, becoming rapidly ragged from the thicket-loving habits 

 of the species and thus probably its complete renew^al is a necessity." 

 But he says that he is not sure that the complete postjuvenal molt 

 occurs in all specimens. Mr. Forbush ( 1929) says that the postjuvenal 

 molt is incomplete, as with other vireos, involving the body plumage 

 and the wing coverts, but not the rest of the wings or the tail. I am 

 inclined to think that Forbush is probably right, for I can find no 

 birds renewing wing or tail feathers at the postjuvenal molt in a 

 considerable series that I have examined. 



The first wdnter plumage is practically the same as the winter 



