490 WEB-FOOTED BIRDS. 



above the back. They breed on trees, on desert shores, or on elevated 

 rocks ; the eggs are only one or two. 



The birds of this group are chiefly tropical, and are formed of but 

 two species, one of which is also doubtful. They are analogous in 

 form and habits to the rapacious birds, especially the Eagles, which 

 they seem to represent among the aquatic tribes. 



