Although crocodiles 

 shallow grass beds, 

 their util ization of 



5.5 Birds 



undoubtedly feed in 

 little is known of 

 this habitat. 



to sieze 



swiiiining 



The seagrass beds of south Florida 

 are used heavily by large numbers of 

 birds, especially the wading birds, as 

 feeding grounds. This heavy utilization 

 is possible because of the relatively high 

 proportion of very shallow grass bed habi- 

 tat. There are few studies of the utili- 

 zation of seagrass beds by birds, al- 

 though there are extensive lists of birds 

 using temperate seagrasses and aquatic 

 plants (McRoy and Helfferich 1980). Birds 

 known to use the seagrass habitat of south 

 Florida and their modes of feeding are 

 listed in Table 9. 



Three common methods of feeding in 

 birds are wading, swimming, and plunging 



from some distance in the air 

 prey. The most common of the 

 birds is the double-crested cormorant 

 which pursues fish in the water column. 

 Cormorants may be found wherever the water 

 is sufficiently deep for them to swim, and 

 clear enough for them to spot their prey. 

 The osprey and the bald eagle sieze prey 

 on the surface of the water with their 

 claws, while the brown pelican pluges from 

 some distance in the air to engulf fishes 

 with its pouch. The value of the seagrass 

 meadows to these birds is that prey are 

 more concentrated in the grass bed than in 

 the surrounding habitat, thus providing an 

 abundant food sourer. 



The extensi' e shallow grass flats are 

 excellent foraring grounds for the larger 

 wading birds 'figure 21). The great white 

 heron is common on the shallow turtle 

 grass flats on the gulf side of the lower 

 Keys. The great blue heron is common 



Figure 21. Shallow seagrasses adjacent to red mangrove roots, 

 ing area of small and medium sized wading birds. 



54 



This is a common feed- 



