STATUS: Species of Special Concern
DESCRIPTION: A medium-small heron, mostly dark slate-blue on head, neck, upper wings and upper body. The chest is purplish, in sharp contrast to a white belly and undertail. Adults show distinctive yellow-brown plumes across the lower back, while immature plumaged birds are quite reddish-brown on the head, neck and wings. The tricolored heron is a particularly slim, long-necked species that stands about 60 centimeters high, and has a 1 meter wingspread.
HABITAT AND DISTRIBUTION: The tricolored heron is closely associated with wetlands throughout Florida, but is most common in estuarine habitats. This species, like most waders, nests on islands or in woody vegetation over standing water. Nests are often located in mangroves, Carolina willow, buttonbush, marsh elder, wax myrtle, pond apple, or similar woody plants characteristic of interior wetlands or estuaries. Tricolored herons nest north along the Atlantic Coast to Massachusetts, and westward in coastal lowlands around the entire Gulf of Mexico. Tricolored herons nest throughout Florida, most commonly in estuarine colonies along the peninsula, less commonly west of the Apalachicola drainage. The species can be found throughout Central America, the West Indies, and the remainder of the United States.
LIFE HISTORY AND ECOLOGY: Tricolored herons feed either singly or in flocks with other species of waders in a wide variety of shallow aquatic sites, both freshwater and estuarine. Tricolored herons nest in colonies with other nesting waders. The number of pairs of tricoloreds in a mixed species colony varies considerably, from a very low figure represented by as few as 1 or 2 pairs in large interior colonies, which may be dominated by cattle egrets, up to 95 percent of the nesting birds in some mangrove island colonies in Florida Bay. Nesting in Florida is initiated as early as February, or as late as July. Most nests contain 3 or 4 eggs. The percentage of active nests that are successful in producing young varies considerably between colonies and years, depending on levels of predation, food availability, and other factors. Tricolored herons feed primarily on small fish, and to a lesser extent on crustaceans and aquatic insects. Tricolored herons employ a variety of hunting techniques, but the most often search for prey by standing motionless, slowly walking, or running in shallow water.
BASIS OF STATUS CLASSIFICATION: In the early 1930s the tricolored heron was considered to be the most abundant heron in the state, with a bird population of approximately 500,000. By the 1970s the number of tricoloreds that nested in extreme south Florida had been greatly reduced and the population throughout the state has generally declined over the last two decades. Because of this and recent trends in destruction of wetlands in Florida, the tricolored heron was classified as a "species of special concern" by the state in 1979.
HABITAT GUIDELINES: Protection of this species consists of providing an effective zone that buffers the nesting sites. This "buffer zone" may extend into upland habitat. The extent of these buffers is based on existing State and/or Federal guidelines, or reflect the recommendations of the Florida Game and Fresh Water Fish Commission.
Any activity proposed within a buffer zone would be subject to review. Activities that could be allowed in the buffer zone would be those activities which would not have any long term detrimental impact on the nesting birds. The following would be considered when making this determination: (1) the type of activity or construction planned and its' long term impacts; (2) the nature of the natural community that makes up the buffer zone (does it provide a visual barrier for any proposed nesting activities?); and (3) the timing of the proposed construction (does it occur outside the nesting season?).
RECOMMENDATIONS: The number of tricoloreds that nest in Florida seems to be proportional to the acreage of productive wetlands, thus the shrinking statewide population of this species presumably represents adjustments by the birds to habitat loss. Halting this trend obviously calls for protection of remaining wetlands, and maintenance or re-establishment of adequate groundwater levels. Important nesting colonies throughout the state should be identified, and monitored, in an attempt to determine the number of tricolored herons remaining in Florida, and where the particularly serious declines are occurring.
Ogden, J.C. 1978. Louisiana heron. Pp. 77-78. In H.W. Kale, II, (ed.), Rare and Endangered Biota of Florida. Birds. University Presses of Florida, Gainesville, FL.
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