WOOD THRUSH 113 



bird would often lift and flutter its wings rapidly when approached 

 by the parent with food, at the same time uttering rapid, squeaky 

 calls. 



Plumages. — The newly hatched wood thrush is clothed in natal 

 down. The juvenal feathers are a continuation of this down, which is 

 carried out on the tip of the new feathers and is finally rubbed off. 

 The down is still present when the young leave the nest. The loss of 

 the down is the postnatal molt. The juvenal plumage is the first 

 complete plumage of the bird following the natal down and is acquired 

 by the growth of new feathers. Sheaths are short and are lost 

 quickly, as a bird when ready to leave the nest has no sheaths on the 

 short body feathers. Therefore, when sheaths are found approxi- 

 mately six weeks later, they are known to be those of new feathers. 

 Then, at six weeks the juvenal plumage is lost by an incomplete post- 

 juvenal molt in which the body feathers are lost but not the flight 

 feathers, neither in wings nor tail. This molt brings the bird into its 

 first winter plumage. 



The first nuptial plumage is supposedly acquired by abrasion or 

 feather wear accomplished by casting the points of the feathers. 

 This takes place on the wintering grounds before spring migration. 



The postnuptial molt is complete, both body and flight feathers 

 being lost. Specimens were found in molt at the end of July. These 

 birds were practically "bob-tailed." At this time the birds are secre- 

 tive in habits, of necessity. 



Wetmore (1936) states that a female weighing 60.4 grams had 

 2,075 feathers, which weighed 3.2 grams. 



Brackbill (1943) banded a partially albino female wood thrush. 

 It had a white feather in the crown, some white feathers among the 

 upper tail coverts, and four white rectrices. The eyes were normal. 

 No sign of the inheritance of this character could be noted in any of 

 the two broods of three young. 



Food. — Thrushes are insectivorous but are fond of fruit. The 

 U. S. Fish and Wildlife Service supplied the following data on the 

 food of this species, based on 179 stomachs examined. These birds 

 were taken from 19 States, 5 from Ontario, Canada, and 19 from the 

 District of Columbia. They were unequally distributed over nine 

 months of the year, the months of May and July yielding more 

 specimens. 



In the 179 examinations, 62.25 percent of the material consisted of 

 animal matter and 37.75 percent vegetable matter. Of the latter, 

 3.49 percent was cultivated fruit and 31.2 percent wild fruit. In 

 general, this bird is beneficial, although 2.17 percent of its food is 

 composed of useful Coleoptera, 8.38 percent of Arachnida, and 3.49 

 percent of cultivated fruit, making a total of 14.04 percent of food 



