THE OOLOGIST 



151 



ing July 4, and this species first 

 reaches the West Indies the second 

 week in August. My personal obser- 

 vation of their movement here ex- 

 tends from July 4 to October 7. What 

 possible physical condition or pres- 

 cience could maintain so uniform a 

 southward movement over such a 

 long period, and through seasonal 

 changes, and all it implies, as corn- 

 comprehended by a comparison of 

 July with October? Why should they 

 migrate at all? Why has not nature 

 modified these warblers to the condi- 

 tion of Chickadees? Perhaps the Myr- 

 tle Warbler is leading and the others 

 following a gradual modification in fa- 

 vor of permanent northern residence. 

 A few Myrtles winter at least as far 

 were probably resident in South 

 America and later all wintered there, 

 and at some distant period may be- 

 come entirely resident on their pres- 

 ent breeding grounds. 



My observations of the local move- 

 ment inclines me to believe that the 

 majority of warblers follow the water- 

 ways, probably because the bordering 

 timber is the most suitable and food 

 more abundant. This refers mainly 

 to the earlier birds traveling by easy 

 stages and not handicapped for time. 

 On occasions they do not hesitate to 

 take a northerly course, if the wood- 

 lands are more congenial to their 

 tastes, but that they retain a correct 

 sense of the direction is plainly shown 

 when a point is reached where further 

 progress would impair the southward 

 movement. This belief is based on 

 observations in Grosse Pointe Town- 

 ship and vicinity where there are no 

 water-ways bordered by timber. Here, 

 on September 3, I discovered a large 

 company of mixed warblers in Gratiot 

 Twp. and followed them about N. 4.", 

 degrees E. across Grosse Pcinte Twp. 

 and Village of Grosse Pointe Farms 

 to the shore of Lake St. Clair. From 

 this point all suitable territory lay to 



the north but they took he 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 degrees 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 ad- 

 vances these naturally increase in 

 numbers as more species become af- 

 fected. 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 in- 

 fluenced from their purpose by con- 

 venient food supply, characteristic so- 

 cial tendency or geographical condi- 

 tions. I spent many hours with the 

 Black-throated Blue Warblers in Oc- 

 tober. They were neither uneasy nor 

 migrating and assisted me as decoys. 

 They always had a friendly call note 

 for passing warblers, but with de- 

 creasing effect as the month advan- 

 ced. 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 

 more Black-throated Blue Warblers 

 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 af- 

 forded me a quick shot but if not, I 

 cculd 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 war- 

 bler soon turned to the south. All 



