VOl i907 IV ] Wood, Autumn Warbler Migration. 325 



north but they took the opposite direction. On the same date 

 another flock came due east and reached the south end of a large 

 woods. They worked through it to the northern margin and back 

 to the starting point ; thence, across the open country about S. 25° W. 

 From the first week in September there are always late warblers, 

 that is, birds passing days behind the bulk of their species. As 

 the season advances these naturally increase in numbers as more 

 species become affected. After early September single birds or 

 small companies are met with that have come to realize they are 

 due miles to the south, and I doubt if they are in any way influenced 

 from their purpose by convenient food supply, characteristic social 

 tendency or geographical conditions. I spent many hours with the 

 Black-throated Blue Warblers in October. They were neither 

 uneasy nor migrating and assisted me as decoys. They always 

 had a friendly call note for passing warblers, but with decreasing 

 effect as the month advanced. A warbler, bent on business, does 

 not fly from tree to tree but takes spurts of about 100 yards and, 

 after hastily snatching a morsel or two of food, repeats the operation. 

 One or two of the Black-throated Blue Warblers would reply to 

 the first far away note of an approaching warbler and the bird 

 would be sure to pass through or above the flock, exchanging 

 greetings but seldom stopping. This often afforded me a quick 

 wing shot but if not, I could sometimes intercept the bird at the 

 woodland margin, as I knew the point where it would leave, and 

 all such warblers remain longer in the last tree than anywhere 

 while passing through the woods. A late Black-poll once joined 

 a passing flock of Robins but they were going west and the warbler 

 soon turned to the south. All warblers seem to me somewhat 

 indifferent to cold, but snow inspires alarm in even the latest, and a 

 general rapid southward movement — the Myrtle excepted. 1 Of 

 the warblers noted October 14, three species were passing more 

 than a month later than the bulk of their kind. In a measure, 

 this is owing to early species getting into flocks of the later kinds 

 and being influenced by them. Another apparent reason is the 



1 They care nothing for the snow in spring if the mercury is above freezing and 

 the food supply not affected. The only Blue-winged Warbler seen this year was 

 located by its song and in a blinding snow storm in early May. I also followed and 

 watched five other species during that storm and they totally disregarded it. 



