BLACK-POLLED WARBLER 393 



The observations and dates of the spring and fall migration made 

 by M. B. Trautman (1940) at Buckeye Lake, Ohio, are typical of 

 the midwestern section of the migration route. He writes as follows : 



The black-poll warbler was among the last of the warblers to make its appear- 

 ance in spring. The latest date for spring arrivals was Jlay 15. In the average 

 year a few could be seen daily after May 15, and by May 18 the species was 

 common. At the peak of migration, between May 18 and 27, 10 to 40 birds could 

 be observed daily. The species then generally disappeared suddenly, for by 

 May 29 all except a few stragglers had departed. 



The first southbound transients were seen between August 31 and September 

 14, and the species was always rare until September 15. An increase became 

 apparent by September 17, and from then until October 10 it could be regularly 

 recorded. The peak of migration came between September 25 and October 10, 

 and then 10 to 150 individuals could be daily observed. A sharp decrease in 

 numbers took place between October 10 and 15, and by October 23 the species 

 was usually absent. « * * 



The black-poll and bay-breasted warblers were close associates during migra- 

 tions. Both were late spring and fall transients, both chiefly inhabited trees, and 

 their maximum numbers during migrations were almost equal. 



In Maine and Massachusetts the main migration wave of blackpolls 

 comes late in May, but a few forerunners can be expected during the 

 second week of the month and a few exceptionally early records have 

 been made during the first week. It is the only one of the transient 

 warblers that remains until June, and in some years a few belated 

 stragglers linger after the second week in southern Maine. It nests 

 in the northern part of the state. 



In autumn the blackpolls arrive in force in September, with some 

 foreruimers appearing late in August. They are with us through 

 September and much of October; in Massachusetts dates of last ap- 

 pearances have been reported for November, and one was seen as 

 late as December 17, 1939, at Plum Island, Mass., by Kichard Stackpole 

 (1939) and others. 



Nesting.— T\\Q, blackpoll is a bird of the northern spruce forests; 

 in fact, the spruce seems to be an essential requirement for its nesting 

 site. At Kent Island, Bay of Fundy, New Brunswick, I have seen 

 9 nests, all in small white spruces and all located within the narrow 

 range of 2 to 7 feet from the ground and built snugly against the 

 trunks of the trees. The somewhat bulky structures were well sup- 

 ported in each case by one or two horizontal branches. Most of these 

 New Brunswick nests were well concealed from view by canopies of 

 overhanging branches. A typical nest had an outside diameter of 

 414 inches and was 3 inches in depth. The internal dimensions 

 of the cup were 2 inches wide and V/o inches deep. The foundation 

 was made of small twigs and sprays of spruce, pieces of bark, dried 

 grasses, and weeds mixed with bits of moss, lichens, and wool. The 



