CHAPTER 9. COMMUNITY COMPONENTS - BIRDS 



9.1 ECOLOGICAL RELATIONSHIPS 



Because mangroves present a more 

 diverse structural habitat than most 

 coastal ecosystems, they should harbor a 

 greater variety of birdlife than areas 

 such as salt marshes, mud flats, and 

 beaches (MacArthur and MacArthur 1961). 

 The shallow water and exposed sediments 

 below mangroves are available for probing 

 shorebirds. Longer-legged wading birds 

 utilize these shallow areas as well as 

 deeper waters along mangrove-lined pools 

 and waterways. Surface-feeding and diving 

 birds would be expected in similar areas 

 as the wading birds. The major difference 

 between mangrove swamps and other coastal 

 ecosystems is the availability of the 

 trunks, limbs, and foliage comprising the 

 tree canopy. This enables a variety of 

 passerine and non-passerine birds, which 

 are not found commonly in other wetland 

 areas, to use mangrove swamps. It also 

 allows extensive breeding activity by a 

 number of tree-nesting birds. 



The composition of the avifauna com- 

 munity in mangrove ecosystems is, in fact, 

 highly diverse. Cawkell (1964) recorded 

 45 species from the mangroves of Gambia 

 (Africa). Haverschmidt (1965) reported 87 

 species of birds which utilized mangroves 

 in Surinam (S. America). Ffrench (1966) 

 listed 94 species from the Caroni mangrove 

 swamp in Trinidad while Bacon (1970) found 

 137 in the same swamp. In Malaya, Nisbet 

 (1968) reported 121 species in mangrove 

 swamps and Field (1968) observed 76 from 

 the mangroves of Sierra Leone (Africa). 



Use of mangrove ecosystems by birds 

 in Florida has not been recorded in de- 

 tail. Ninety -two species have been ob- 

 served in the mangrove habitat of Sanibel 

 Island, Florida (L. Narcisse, J.N. "Ding" 

 Darling Natl. Wildlife Refuge, Sanibel 

 Is., Fla.; personal communication 1981). 

 Robertson (1955) and Robertson and Kushlan 

 (1974) reported on the entire breeding 

 bird fauna of peninsular south Florida, 

 including mangrove regions. Based on 

 limited surveys, these authors reported 

 only 17 species as utilizing mangroves for 

 breeding purposes. Because their studies 

 did not consider migrants or non-breeding 



residents, a significant fraction of the 

 avifauna community was omitted. 



Based on information gleaned from the 

 literature, we have compiled a list of 181 

 species of birds that use Florida mangrove 

 areas for feeding, nesting, roosting, or 

 other activities (Appendix D). Criteria 

 for listing these species is the same as 

 that used for listing reptiles and amphi- 

 bians (see Chapter 8 of this volume). 



Often references were found stating 

 that a given species in Florida occurred 

 in "wet coastal hammocks", "coastal wet 

 forests" or the like, without a specific 

 reference to mangroves. These species 

 were not included in Appendix D. Thus, 

 this list is a conservative estimate of 

 the avifauna associated with Florida man- 

 grove swamps. Sources for each listing 

 are provided even though many are redun- 

 dant. Food habit data are based on Howell 

 (1932) and Martin et al. (1951). Esti- 

 mates of abundance were derived from bird 

 lists published by the U.S. Fish and 

 Wildlife Service for the J.N. "Ding" 

 Darling National Wildlife Refuge at 

 Sanibel Island, Florida, and by the Ever- 

 glades Natural History Association for 

 Everglades National Park. Frequently, 

 species were recorded from mangrove swamps 

 at one location, but not the other. 



We have divided the mangrove avifauna 

 into six groups based on similarities in 

 methods of procuring food. These groups 

 (guilds) are the wading birds, probing 

 shorebirds, floating and diving water- 

 birds, aerially-searching birds, birds of 

 prey, and arboreal birds. This last group 

 is something of a catch-all group, but is 

 composed mainly of birds that feed and/or 

 nest in the mangrove canopy. 



9.2 WADING BIRDS 



Herons, egrets, ibises, bitterns, and 

 spoonbills are the most conspicuous group 

 of birds found in mangroves (Figure 14) 

 and are by far the most studied and best 

 understood. Eighteen species (and one 

 important subspecies) are reported from 

 south Florida mangroves. 



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