IV-107 



and the trials of several other groups, such as the egrets, have 

 received periodic publicity. Among the bird life most threat- 

 ened by changing environmental conditions, especially in the 

 estuaries, are the larger fish-eaters of the Nation's coast. 



The brown pelican has already disappeared from the Gulf coast 

 of Alabama, Mississippi, Louisiana, and Texas, where it was a 

 common sight prior to 1960. This disappearance coincided with 

 the heavy fish kills of 1960-1964 in the Lower Mississippi River, 

 which were caused by excessive residues of pesticides. One 

 theory proposed that the dead and dying pelicans observed during 

 that period had accumulated lethal dosages (Figures IV. 2. 9). 

 This assumption, however, was not verified and another theory 

 used to explain the lack of any recovery was the destruction of 

 nesting grounds in black mangroves by the severe cold. 



The 80 species of waders, which include the egrets, storks, 

 herons, ibis, and spoonbills, are predominantly residents of the 

 southern United States, particularly in Florida. The recent 

 drought and man-made changes in the Everglades have drastically 

 reduced the number of these species in Florida. For some species, 

 this represents a serious setback in their gradual recovery from 

 near extinction at the hands of the plume hunters. Waders else- 

 where on the southern coast have also diminished in numbers, 

 apparently because of irresponsible shooting and man-made envi- 

 ronmental changes. 



