partitioning, white ibis are more 

 mobile and flexible than wood storks 

 in their nesting and foraging habi- 

 tats and requirements, but both are 

 nonetheless dependent on seasonal 

 water level fluctuations. 



Unfortunately this comparison 

 is both very incomplete and includes 

 only two of many wading birds appar- 

 ently utilizing the same resource. 

 No doubt a fascinating mosaic of 

 resource partitioning exists among 

 the variety of species exhibiting 

 superficially similar "niches". The 

 general trend in nesting of wading 

 birds is to utilize the freshwater 

 wetlands during wet years but to 

 fall back on the more stable produc- 

 tivity of the mangrove zone during 

 dry years (Odum et al. 1982). 



Of the 25 species of probing 

 shorebirds that are reported from 

 the mangrove zone only two, the wil- 

 let and the clapper rail, are year 

 round residents. The clapper rail 

 and black necked stilt breed in the 

 mangrove zone while the remaining 22 

 species are transients (Odum et al. 

 1982). In general, the mangrove 

 zone is limited in its availability 

 of suitable habitat for these birds; 

 they prefer a variety of more open 

 habitats such as marshes and sandy 

 beaches. 



Surface and diving birds of the 

 mangrove zone include 19 species of 

 ducks, 2 grebes, 1 loon, 2 cormo- 

 rants, 3 gallinules, and 2 pelicans. 

 Table 33 summarizes the feeding 

 habits of some of these birds. 



Many of these birds are perma- 

 nent residents that feed as well as 

 nest in the mangrove zone. However, 

 exclusive use of mangroves by this 

 guild of birds is not the rule. The 

 anhinga prefers freshwater habitats, 

 while almost all of the other birds 

 utilize either the offshore or 



interior wetlands as well as the 

 estuaries (Odum et al. 1982). 



Table 33. Trophic relations of 



surface and diving birds 

 in the mangrove zone. 



Aerially searching birds in- 

 clude 11 species of gulls and terns, 

 the black skimmer, the belted king- 

 fisher, and the fishcrow. Owing to 

 their generally similar modes of 

 feeding and food sources, most of 

 these birds are in the primary to 

 middle carnivore range. The gulls 

 tend to eat more of a variety of 

 prey, including insects, snails, 

 crabs, and fish, while the terns and 

 others rather exclusively dine on 

 small fish (Sprunt 1954, Odum et al. 

 1982). Nesting colonies of these 

 species in Florida are generally 

 restricted to the more open mangrove 

 keys and islands of Florida Bay and 

 the Florida Keys. 



Birds of prey reported from the 

 Florida mangrove zone number 18, 

 though not all are permanent resi- 

 dents. Of these, 7 are considered 

 mangrove dependent based on their 

 food habits. Osprey, bald eagle, 

 and the magnificent frigate bird 

 rely heavily on a fish diet, while 

 the peregrine falcon and the merlin 

 are known to take shore birds as 



162 



