29O Kopman, Warbler Migration in La. and Miss. [fal^ 



New Orleans are entirely inapplicable to the same birds as occur- 

 ring in the piney country about Bay St. Louis. Species that ar- 

 rive in numbers and with regularity at both places in spring and 

 fall arrive at practically identical times, but there is a consider- 

 able number of birds which will be found in important numbers 

 at one of these points at one season and not be found at the 

 other. And this difference is of much more significance than 

 might seem at first. New Orleans is on a rather low, alluvial 

 plain, a country in large part swampy, with few characteristic tree 

 growths except the water oak, the live oak, the tupelo gum, and 

 the bald cypress. Bay St. Louis, on the other hand, is about fif- 

 teen miles east of the western limit of the piney belt in its coast- 

 ward extension (the delta and immediate valley deposit of the 

 Mississippi covering the lands about New Orleans that otherwise 

 would be pine-bearing). Bay St. Louis, moreover, is on rather 

 high ground, completely of white sand and red and yellow clay 

 formations, and has a highly characteristic tree and shrub flora, 

 of which the pines are most conspicuous. It can be seen, there- 

 fore, that many important distinctions in the avifauna are to be 

 found when we compare the two districts. Some birds that 

 migrate with regularity through the country about Bay St. Louis 

 in spring, put in an appearance at New Orleans only occasionally, 

 and vice versa. In the present instance, the trouble is that by far 

 the larger part of the data have come from New Orleans, and the 

 Bay St. Louis data, especially in regard to spring, have been used 

 to supplement our reports for the New Orleans district. But the 

 story of the migrations told us by the New Orleans records, is 

 much more than supplemented, in many cases, by the observa- 

 tions made on the Mississippi coast. There are things brought 

 out in the records from that district which we should never have 

 discovered from the returns at New Orleans. In other words, the 

 Bay St. Louis district is part of a distinct faunal area, and in its 

 bearings to migration as well as to every other phase of bird-life, 

 should be treated as such. 1 



1 Some of the differences between the avifauna of the fertile alluvial of 

 southeast Louisiana and that of the pine districts to the north and east in 

 Louisiana and Mississippi were pointed out by me in an article in ' The Gulf 

 Fauna and Flora Bulletin,' Vol. I, No. 2. 



