l6 MEMOIRS OF THE NUTTALL ORNITHOLGICAL CLUB. 



often the greatest difficultly in securing such representatives of even tlie 

 commonest species. 



My experience with species which come from further north is that the 

 first fliglits are composed largely, and often entirely, of old birds. The 

 reason why this fact has been overlooked, or even positively' denied by so 

 many observers, becomes apparent when we consider tlie dates at which 

 even the earlier autumnal migrants are said to reach Massachusetts from 

 the north. Almost without exception the time is fixed somewhere in Sep- 

 tember, and I venture to say that the majority of New England collectors 

 still believe that September i inarks about the beginning of the autumnal 

 migrations. This impression has resulted from the fact that our collectors 

 are usually absent at the mountains or seashore during August. Even if 

 obliged to pass the dog daj's nearer home, they rarely think of taking the 

 field at a time when it is supposed that there is nothing of value to be had 

 there. The weather is hot and enervating, the foliage is at its densest, 

 "birds are silent and hard to find, and most of them in such ragged 

 plumage that they are worthless as specimens." 



Now the simple truth is that the migrations of most of our small birds 

 begin early in August. During the last two weeks of that month there are 

 usually several real " rushes," when the woods throughout Eastern Massa- 

 chusetts are filled with such northern species as Tzirdiis szt'oinsoni. Sitia 

 canadensis, Dendroica coroiiata, D. maculosa, D. blackburniie, D. cas- 

 tanea, Sylvania pusilla, S. canadensis, Sciurus noveboracensis , Empidonax 

 jlaviventris, etc. 



In these August fliglits I have always found a large percentage of, and 

 in some cases nothing but, old birds.* Towards the close of the month the 

 proportion of young to adults increases daily, and after September i it is 

 rare to find more than one or two old birds in even the largest mixed flocks. 



There are apparent exceptions to this rule, a marked one being Oporornis 

 agilis. This species arrives at Cambridge about September 12, and during 

 the remainder of the month is so abundant in the Fresh Pond swamps that 

 from ten to twenty specimens may be often found there in a single day. The 

 adults, however, are so very uncommon that I have never known them 

 represent more than five per cent of the total number of individuals. They 

 do not seem to be more numerous in the earlier flights than towards the close 

 of the month, and I am very sure that they cannot be found in this locality 

 before the yotmg begin to appear. Nevertheless I believe (although I have 

 no proofs of such a theory) that they, in common with the adults of other 



*Neai- Cambridge, Mass.. on August 23, 1884, I met with a flock of about twenty Dendroica 

 coronata, all adults, in various stages of moult. Thej of course came from further north, as 

 the species does not breed in Massachusetts. Who has ever found such a flock in September? 



