19CXS ] Beyer, Allison, Kopman, Birds of Louisiana. 5 



in the State in various roles according to the season, and conse- 

 quently their dispersion throughout this region will show much 

 variation. These remarks apply especially to the Terns, the 

 Herons, and the Rails, and to such semi-aquatic species among 

 the higher orders as the Red-winged Blackbird and the Seaside 

 Sparrow. 



A feature of the immediate delta and southeast coast region of 

 interest is the presence of hundreds of islands, some purely marshy, 

 some more or less sandy, a few formed chiefly of shells, and still 

 others formed entirely from the muddy deposits of the Mississippi, 

 according, in each case, to the relative influence exerted by the 

 building operations of the sea and by those of the river. The 

 character of these islands is of great importance in studying the 

 distribution of the terns on the coast, and is a subject that has 

 scarcely been touched yet from a careful ecological standpoint. 



The chief shrubby and arboreal growth of these islands is wax 

 myrtle and dwarfed live oaks. The fishermen of the region often 

 speak of 'mangrove,' but they use the word as a generic term. 

 Prof. S. M. Tracy, expert of the U. S. Department of Agriculture 

 and resident on the Gulf Coast, tells us that he has never found 

 the mangrove on the islands about the mouth of the Mississippi, 

 and that he doubts exceedingly its occurrence so far north. 



In the main body of the marsh — what, in fact, might be called 

 mainland — the occurrence of thickets and ' islands ' of wax myrtle 

 and small live oaks is characteristic. The more important growth, 

 along some of the streams and about the borders of the 'lakes,' is 

 chiefly cypress; these cypress brakes are outrunners of the swamps 

 further inland. 



At the latitude of New Orleans, except for the little marshy 

 corner of the State on the east, and one or two similar small regions 

 to the west, the continuity of the swamp woodland is practically 

 unbroken, except for the water surfaces. Here again, however, 

 there are small but important distinctions to be made. Owing to 

 the continual elevation of the flood plain of the Mississippi, dis- 

 tricts along the bank of the river have been raised entirely above 

 the level of Standing swamp water, while water from overflow has 

 been made the rare exception by the levee system. Consequently, 

 there is a considerable amount of comparatively dry woodland in 



