4 Beyer, Allison, Kopman, Birds of Louisiana. [jan 



ramification of its sluggish bayous, and the impenetrability of its 

 cypress fastnesses need hardly be reiterated wherever the literature 

 of the time is known. In the particularly water-broken territory 

 in the region of the lower Mississippi, however, there are features 

 worth notice from a distributional standpoint. The region under 

 immediate consideration lies between the 89th and 92nd degrees 

 of west longitude and between the 29th degree of north latitude 

 and a line following rather closely the northern shores of Lakes 

 Pontchartrain and Maurepas, westward to about New Iberia, in 

 central southern Louisiana. Such a line gives about the extreme 

 southern breeding limit of the Baltimore Oriole, the Yellow- 

 throated Vireo, and the Yellow Warbler. Continued still farther 

 westward, to Lake Charles, in southwest Louisiana, this line in 

 its full extent will give about the beginning of the rise to the high- 

 lands of the State, which are pronounced at such points as Coving- 

 ton, Baton Rouge, and Opelousas. New Orleans, on the other 

 hand, is in the very heart of the typical low alluvial plain. 



The marshes of southeast Louisiana extend in from the coast 

 for varying distances, according to the conformation of the 'lakes,' 

 and the courses of the streams. Whether the 'lakes' are salt or 

 fresh depends, of course, upon the distance from the sea, and the 

 volume of the streams with whose outflow they come into contact. 

 The 'lakes' are merely the remains of former marginal bays, and, 

 at present, the streams not only flow into them, but, in a majority 

 of cases, flow out of them again. Lake Pontchartrain, though 

 landlocked except for several small outlet channels, is compara- 

 tively salt. Some of those now a considerable distance inland, on 

 the other hand, exhibit no salinity whatever. Just as between the 

 fresh 'lakes' and the salt 'lakes,' no sharp line can be drawn, so 

 between the latter and the ordinary inlets and bays of the Gulf, 

 no exact distinction can be made. The consequent variability of 

 the character of the marsh is readily appreciated. 



It will be seen also that this variability is important in determin- 

 ing the comparative abundance of water birds in different localities 

 of a region which casual inspection might pronounce uniform. 

 As the seasons change, and with them the nature of avian require- 

 ments, certain species in this region show varying choices of local- 

 ities. Moreover, different individuals of the same species appear 



