OLIVE-BACKEU THRUSH. 673 



like notes may be lieard echoing through the wooded glens which was at one time their 

 only place of resort. Now, however, they frequent small groves in the vicinity of houses, 

 and on account of protection thus afforded them are rather increasing in numbers. The 

 nest is built the last of May and 1 have found newly hatched young as early as June 4th. 

 As a rule the Wood Thrush makes no attempt at concealing its nest placing it in the fork 

 of a bush or low tree in open siglit. Tlie birds sing more frequently in the morning and 

 evening and when so engaged is often perched in some elevated situation. In the autumn 

 of 1867 the Wood Thrushes remained in Massachusetts as late as October 10th, but I think 

 that they usually migrate somewhat earlier than this. 



TURDUS SWAINSOMil. 

 Olive- backed Thrush 



Turdus swainsonii Cab, in Tschudi, F. Peruana, 1844^6, 188. 



DESCRIPTION. 

 Sp. Cii. Form, not very robust. Bill, rather short and stout. Tongue, narrowing towards the ter- 

 minal half ; bifid and fringed for about one-third its length. Breadth of sternum generally exceeding the 

 depth of the marginal indentations. Color. Adult. Above, uniform olivaceous brown, varying somewhat 

 in intensity. Under parts, white, with the chin, throat, upper part of breast, ring around eye, sides of head, 

 and a stripe in front of eye, decidedly tinged with rufous. The throat and breast are also spotted with dark 

 brown and olivaceous. These spots, which vary in number and size, are darker on the upper, and lighter on 

 the lower part of the breast. Flanks, olivaceous. Under tail coverts, pure white, with the edges occasion- 

 ally tinged with olivaceous. Under side of tail and of wings, olivaceous, with a pale buff bar starting from 

 the inner edges of the latter and extending across them. Iris and feet brown. Bill, dark brown, with the 

 base of the lower mandible pale yellow. Young, with two bars on the wings formed by the yellswish tips of 

 the coverts. Lesser wing coverts with light central stripes to the feathers. The extreme ends of the wing 

 and tail feathers are sometimes narrowly tipped with white. The bars on the under sides of the wings are 

 more extended and better defined than in the adult. Nestling plumage The following description is taken 

 from a young bird in this plumage, kindly loaned me by my friend, William Brewster, and it is the only one 

 I over saw in this stage. General colors above and below, similar to the adult. The center of each feather 

 on the entire upper portion, however, has a stripe of rufous, which widens at the extremity. The triangular 

 spots on the wing coverts are much more prominent in this stage than in the last. The spots on the breast 

 are somewhat broader, on account of the webs of the feathers not being as closely blended as in the adult. 

 The bar beneath the wmg is perhaps wider, the colors being more diffused. The bill and feet are paler. 



OBSERVATIONS. 



This species may be distinguished from all others, excepting T. aliciae, for which see description, by the 

 uniform olivaceous color of the back and tail. T. fuscescens is uniform on the upper parts, but the color is 

 reddish. T. swainsonii differs from T. pallasii, another closely allied species, in having the back and tail 

 uniform ; the tail of T. pallasii being much more rufous than the back. The Olive-backed Thrush is dis- 

 tributed, during the breeding season, throughout that section of North America that lies between latitude 

 44 degrees and the Arctic circle. A few winter in Florida, but the greater part pass into South America. 



DIMENSIONS. 



Average of twenty-eight specimens. Length, C>M to 7.76 ; stretch, 10.50 to lli.OO ; wing, 3.00 to 4.4U ; 

 tail, 3.00 to 4.00 ; bill, .47 to Sm ; tarsus, 1.14 to 1.50. 



