Bancroft et al. (1994) examined general foraging distribution data from systematic aerial 
surveys, specific foraging distribution data obtained from following flights, habitat data from 
the USGS orthophotomaps, hydrological data from gauges and aerial surveys, and colony 
location, size, and sucess data from three recent studies were analyzed. Nesting great egrets 
and white ibises typically foraged within 9 and 10 km, respectively, of their colonies. 
Historically, these species bred in large, mixed-species colonies in the mangrove zone of 
Everglades National Park, whereas currently they breed in much smaller colonies in the water 
Conservation Areas. Examination of the formation, growth and decline of a colony in the Water 
Conservation Areas during the drought year 1989 showed that initially the nesting birds were 
feeding close to the colony. As the area dried out, the overall foraging distribution shifted well 
south of the colony. The compartmentalization of the Everglades may have decresed the ability 
of forage fish to migrate through the system, especially into the deeper sloughs during the dry 
season, thus decreasing the productivity of these areas for nesting wading birds. 
Ogden (1994) examined patterns of nesting for five species of colonial wading birds in the 
central and southern Everglades for two periods: an early drainage period (1931 - 1946) and a 
late drainage period (1974 - 1989). Parameters examined were (1) numbers of birds nesting in 
each colony, (2) locations of colonies, (3) timing and nesting, and (4) colony success. The five 
species analyzed were great egret, tricolored heron, snowy egret, white ibis, and wood stork. 
For all species except the wood stork, the locations of the largest colonies changed between 
periods from a headwaters subregion located at the lower end of the Shark River Slough to a 
central Everglades subregion located north of Everglades National Park. Reductions in the 
number of nesting birds and changes in the location of major colonies appear to correlate with 
the reduction in the total area of wetland foraging habitat, an increased frequency of extensive 
dry outs in the lower Shark River Slough marshes, and the relocation of the longer hydroperiod 
marshes into the Water Conservation Area impoundments. 
6.10. Fires in the Everglades National Park 
Fire and water are the two major natural factors affecting the environment of south Florida. 
Fires are part of the natural cycle of terrestrial and wetland communities, and are a natural 
means of maintaining specific ecosystems (Hofstetter, 1984). Fires are part of the recycling of 
nutrients. Fires prevent the invasion of grasslands by woody plants, and when fire is excluded, 
community succession continues, eventually ending with the climax community for that region. 
For southern Florida, the climax community is hardwood hammock. Natural fires are caused by 
lightning and are a wet season phenomenon. Lightning may also trigger fires during the dry 
season. These can be extensive and can consume peat, sawgrass and forest. The frequency of 
fires resulting from incendiary activities has increased in recent years. The largest fires in the 
Everglades National Park have been incendiary dry season fires. A detailed description of the 
effects of Everglades fires on the vegetation and animals of the Park can be found in Hofstetter 
(1984). 
Fire records for the Everglades National Park, from 1948 through 1979, are reported in 
Taylor (1981). Number of fires and acres burned by year are listed in Table 13. The records 
contain 913 fire reports of which 682 reports cover 451,082 burned acres in Everglades 
National Park, and 251 reports cover 480,080 burned acres in the Everglades Fire Protection 
Zone outside the park. The recorded fires are categorized as human-caused, lightning-caused, 
or prescribed management fires. Total acres burned by each fire type are presented by year 
and month of occurrence. The number of human-caused fires was found to be highly correlated 
with water levels at Taylor Slough Bridge and with precipitation at Royal Palm. Extreme fire 
years, when 20,000 to 100,000 acres may burn, follow an average interval of 6 to 8 yrs; 
moderate to severe fire years, when 10,000 to 20,000 acres may burn, occur on a 3.2- to 
4.3-yr interval. The Everglades National Park has been divided into three fire management 
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