1S84.] BiCKNELi, Oil tlic S/ni^rii/a- 0/ /Uri/n. 217 



prise and chas^rin I discovered that it jiroceeded from the Hooded 

 Warbler, wliich had been constantly about me, l)ut which I had 

 never suspected to possess such versatility. 



Myiodioctes canadensis. Canadian Fi.vcatciiing 

 Wahbi.eij. 



Myiodioctes pusillus. Black-capped Flycatching 

 VVarblek. 



Both these species are in full song^ while passing in the spring, 

 but I have never heard either sing on the opposite migration in 

 the autumn. Then they appear w'ith perfected plumage and 

 usually with considerable fat. 



Setophaga ruticilla. American Redstart. 



In some years I have found this species songless soon after the 

 beginning of jnly. In seasons when it thus early becomes silent 

 singing is resumed in the first part of August, and continues for 

 two or three weeks. But the period of July silence is inconstant, 

 and sometimes singing is little interrupted through the month. 

 When this is the case singing seems to cease finally at the end of 

 the month or early in August, and is followed b}' no supplemen- 

 taiy song-period. It is not probable that these indications of my 

 records have resulted from incomplete observations ; for records 

 of the time of singing and silence of other birds go to show that the 

 singing of a species in what is normally its central time of silence 

 is at the expense of later song ; and that the supplementary song- 

 period is sometimes thus wholly sacrificed. My dates of last 

 songs are limited by the third week of August, except in one 

 exceptional instance when one of the birds was heard to sing on 

 September 5. In the summer a song is commonly heard from 

 the Redstart which is weaker and otherwise difierent from the 

 normal, and which is probably produced by immatui-e males. 



Vireo olivaceus. Red-eyed Vireo. 



A most untiring vocalist, maintaining song almost uninterrupted- 

 ly through the summer, and only relinquishing it in September — 

 from the ist to the loth. My records fail to show any regular 

 time of silence before this : but singfino; is at a low ebb about 



