138 University of California Publications in Zoology [Vol. 30 



at intervals during the summer. After the middle of August they 

 were more frequently encountered, migrating through the poplar 

 woods in company with other warblers. Last definitely recognized on 

 August 28, though others may have been included with "orange- 

 crowned warblers" seen on August 31. 



Nine specimens were collected (nos. 44904-44912), five' breeding 

 adults, three in juvenal plumage, wholly or partly, and one immature 

 female in first winter plumage, taken August 28. A young bird 

 collected August 21 is still mostly in juvenal plumage. 



In my opinion orestera is a valid subspecies, and on the basis of 

 the characters ascribed to it by Oberholser (1905, p. 243). It is 

 slightly duller colored than lutescens, much brighter yellow than celata, 

 and of greater size than either. The juvenal plumage of orestera, as 

 shown by young birds from the Atlin region, is gray ; juvenal lutescens 

 is yellow. 



It will be of interest to ascertain the dividing line between the 

 breeding ranges of celata and orestera in the north. This is some- 

 thing that is as yet but imperfectly understood, and it will be a difficult 

 line to draw^ Atlin specimens of orestera are not typical of that sub- 

 species in that they are smaller (or at least shorter winged) than those 

 from more southern points. This may, perhaps, be evidence of inter- 

 gradation toward celata. 



Vermivora peregrina (Wilson). Tennessee Warbler 



Breeds in small numbers in the lowlands of the Atlin region. 

 Three specimens were collected (nos. 44913-44915), an adult male on 

 June 29 and two females on tftily 14, all in poplar woods. The species 

 was not otherwise positively identified. 



Dendroica aestiva aestiva (Gmelin). Eastern Yellow Warbler 



Common in the lowlands of the Atlin region, and here, as in most 

 places, showing a predilection for willow copses. First arrival noted 

 May 31, last seen August 26. 



Eleven specimens were collected (nos. 44916-44926), three adult 

 males, two adult females, three males aiid one female in juvenal 

 plumage, male and female in first winter plumage. I refer these birds 

 to the eastern subspecies, Dendroica aestiva aestiva, as the form they 

 most nearly resemble. Such variation as is exhibited from the average 

 of aestiva is shown in a slight darkening of the dorsum, in which 



