STATUS: Species of Special Concern
DESCRIPTION: The little blue heron is a medium size wading bird about 60 centimeters in length; the sexes are similar. The head and neck of adults are purplish-maroon. The rest of the plumage is slate-blue. The distal third of the bill is black. The remainder of the bill and orbital skin are dark grey and the iris is yellowish. The legs are greenish-grey. During the breeding season, the basal portion of the bill and orbital skin are cobalt and long lanceolate plumes become prominent in the crest, lower neck, and the back. The plumage of juveniles is white with slate-grey tips on the primaries. Subadults begin to acquire the dark plumage during their first winter and become pied or calico plumaged.
HABITAT AND DISTRIBUTION: In Florida, little blue herons occur in shallow freshwater, brackish, and saltwater habitats. Their nesting vegetation varies considerably, breeding in cypress, Carolina willow, red maple, buttonbush, red mangrove, cabbage palm, and Brazilian pepper. Little blue herons breed along coastal and adjacent states from Massachusetts to Texas. They also breed in South America. The largest breeding colonies appear to be on the coast and associated islands. Little blue herons, especially juveniles, are noted for their postbreeding dispersal.
LIFE HISTORY: The breeding season in Florida lasts from February to September. Little blue herons nest in both mixed species and single species colonies. Few subadults (pied or calico plumage) breed during their first year, totaling only about 2 percent of the breeding population. The little blue heron exhibits the typical pairing sequence of ardeids. The male sets up a territory and begins displaying. After accepting a female, the male collects twigs and presents them to the female, who constructs the nest. The eggs are pale bluish-green, averaging about 3 per clutch. The fledgling rate is about 2 young per nest. Little blue herons seem to prefer freshwater habitats for foraging, even when they breed on coastal islands. Prey items consist of small fish, frogs, and invertebrates.
BASIS OF STATUS CLASSIFICATION: Population estimates in Florida indicates a decrease in numbers over the past few decades. Because of this and recent trends in destruction of wetlands in Florida, the little blue heron was classified as a "species of special concern" by the Florida Game and Fresh Water Fish Commission 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: Both federal and state laws protect little blue herons. Establishment of sanctuaries and wetland preserves are needed to protect breeding and foraging habitats. Long-term studies on the possible adverse effects of the Cattle Egret (Ardeola ibis) on little blue heron breeding areas may be useful in assessing available habitat. Reproductive rates and population dynamics in both freshwater and marine environments should be monitored closely during the next few decades to establish overall population trends.
Rodgers, J.A., Jr. 1978. Little blue heron. Pp. 72-73. In H.W. Kale, II, (ed.), Rare and Endangered Biota of Florida. Birds. University Presses of Florida, Gainesville, FL.
Content updated Date July 20, 2004