VIRGINIA'S WARBLER 123 



A partial prenuptial molt occurs between February and May, mainly 

 about the head, during which the chestnut crown patch is at least par- 

 tially assumed and the young birds become almost indistinguishable 

 from adults. There is, however, considerable individual variation 

 in the advance toward maturity. 



Subsequent molts consist of a complete postnuptial molt in July and 

 August, and a partial prenuptial molt in early spring. The adult 

 male in the fall is browner above and on the flanks, and the yellow on 

 the chest is duller than in the spring, while the chestnut crown patch 

 is concealed by brownish gray tips. The female, also, is browner than 

 in the spring, with little if any yellow on the chest and with the crown 

 patch similarly concealed. In spring birds there is much individual 

 variation, perhaps owing to age, in the amount of yellow on the breast, 

 throat, and chin. Some females are nearly as brightly colored as are 

 the duller males, some have very little yellow on the chest and some 

 lack the chestnut crown patch. 



Food. — Our information on the food of Virginia's warbler is limited 

 to the observation of Bailey and Niedrach (1938) who saw a pair of 

 these warblers feeding their young on the caterpillars that eat the 

 foliage of the trees and shrubs on their nesting grounds. It is sig- 

 nificant that after these caterpillars are no longer available the warbler 

 leaves its breeding haunts and moves down into the foothills, perhaps 

 in search of other food; and it would be interesting to learn what 

 that food is. It has been seen foraging on the ground, as well as in the 

 foliage, and flying up into the air to capture insects on the wing. 



Behavior. — Virginia's warbler is a shy, retiring species, spending 

 most of its time not far above the ground in the thick underbrush, 

 where it is not easily seen, as its colors match its surroundings. It is 

 also very lively and active, almost constantly in motion, except when 

 it mounts to the top of some dead bush or small tree to sit and sing. 



Voice. — Dr. Chapman (1907) quotes C. E. Aiken as follows: "The 

 male is very musical during the nesting season, uttering his sioee 

 ditty continually as he skips through the bushes in search of his 

 morning repast ; or having satisfied his appetite, he mounts to the top 

 of some tree in the neighborhood of his nest, and repeats at regular 

 intervals a song of remarkable fulness for a bird of such minute 

 proportions." Henry D. Minot (1880) calls the "ordinary note, a 

 sharp chip; song, simple but various (deceptively so) ; common forms 

 are che-we-che-we-cM-we-che-we, wit-a-wit-wit-ioit (these terminal 

 notes being partially characteristic of Helminthophagae) and che-we- 

 che-'we-Ghe-we,che-a-che-a-c7ie'\ Dr. Linsdale's (1938) comments on 

 singing males follow : 



The song varied from 7 to 10 notes, being usually 8, and it occupied about 

 3 seconds. At the beginning the notes were slow and they came more rapidly 

 at the end. About half a minute elapsed between songs." Another bird "sang 



