324 Wood, Autumn Warbler Migration. [julv 



and had the bird been released after that period it probably would 

 have perished from loss of that mysterious guidance to the south, 

 but, opposed to this, we find the latest warblers the most eager 

 to accomplish their journey. To my mind the early migration 

 demonstrates an instinctive movement. Nothing would seem 

 more natural than the warblers retreating after experiencing actual 

 contact with cold or lack of food, but the first birds are on their 

 way long before the least intimation of cold and while food is 

 abundant. I have seen several small flocks of juvenile Redstarts 

 migrating July 4, and this species first reaches the West Indies the 

 second week in August. My personal observation of their move- 

 ment here extends from July 4 to October 7. What possible 

 physical condition or prescience could maintain so uniform a 

 southward movement over such a long period, and through seasonal 

 changes, and all it implies, as comprehended by a comparison of 

 July with October? Why should they migrate at all? Why has 

 not nature modified these warblers to the condition of Chickadees ? 

 Perhaps the Myrtle Warbler is leading and the others following a 

 gradual modification in favor of permanent northern residence. 

 A few Myrtles winter at least as far north as Maine. At one time 

 they were probably resident in South America and later all wintered 

 there, and at some distant period may become entirely resident on 

 their present breeding grounds. 



My observations of the local movement 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 woodlands are more 

 congenial to their tastes, but that they retain a correct sense of 

 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 Township 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. 45° E. across Grosse 

 Pointe Twp. and Village of Grosse Pointe Farms to the shore of 

 Lake St. Claire. From this point all suitable territory lay to the 



