282 BULLETIN 19 7, UNITED STATES NATIONAL MUSEUM 



not quite sure, but think that she did the same with him. * * * 

 My Yellow-throats were very faithful to their young, of which there 

 were three. The male fed them as attentively as did the mother. On 

 July 7, nearly a month from the beginning of the brooding, the first 

 young bird left the nest. It seemed to take good care of itself, keep- 

 ing to the trees, and the next day the other two followed it." 



He discovered great clutching power in the feet of one of the young 

 that he picked up on the lawn. This w^as evidently of great service 

 to the young while tossed about in the nest, for he says : "Through 

 many thunder storms which came to us in that month of June I have 

 seen that slight branch from the body of the elm whip in the blast 

 as if it would be torn from its setting in the great trunk. The nest 

 would be top-down and driven every way, and yet never a fledgling fell 

 from its place. No wonder there had come a development of clutching 

 power!" 



Plumages. — Dr. Dwight (1900) says that the natal down of the 

 yellow- throated vireo is drab, and he describes the juvenal plumage 

 as "above, smoke-gray. Wings and tail black, edged with olive-gray, 

 the secondaries and tertiaries with olive-green (the two inner ter- 

 tiaries white edged), the greater and median coverts with dull white 

 forming two wing bands. Below, silky white, the chin, throat and 

 sides of head pale canary-yellow, the orbital ring, ocular region and 

 superciliary stripe still paler." 



A partial postjuvenal molt, involving all the contour plumage and 

 the wing coverts, but not the rest of the wings or the tail, occurs in 

 July and August. This produces the first winter plumage, which is 

 practically indistinguishable from that of the adult. The upper- 

 parts are now bright olive-green, the wing bars are pure white, and the 

 throat and breast are bright canary yellow. 



The sexes are much alike in all plumages, but the female is usually 

 somewhat paler than the male in adult plumage. There is appar- 

 ently no spring molt, and wear and fading are not pronounced. 

 There is a complete postnuptial molt late in summer, mainly in 

 August. 



Food. — Reporting on the contents of 160 stomachs of the yellow- 

 throated vireo, collected during the months of April to September, 

 inclusive, Dr. Edward A, Chapin (1925) says: "The yellow-throated 

 vireo cats comparatively little vegetable food, practically none during 

 April and May, none during June and July, less than 2 percent in 

 August, and less than 9 percent in September. The average for the 

 year is only 1.74 percent. Among the items specifically determined 

 were sassafras berries and seeds of wild grapes. No cultivated fruit 

 of any kind was found." 



The animal food was made up of 95.82 percent insects, 2.38 percent 

 spiders, and 0.06 percent other animal matter. 



