Tricolored Heron Life History

Habitat

Tricolored Herons use coastal estuaries, saltmarshes, mangroves, and lagoons during the breeding season. They typically breed on islands with small trees or shrubs. Outside of the breeding season they use coastal areas as well as freshwater marshes, lake edges, canals, and ditches.

Food

Tricolored Herons forage for small fish such as topminnows and killifishes in open or semiopen brackish wetlands. They are skilled at stalking, chasing, and standing-and-waiting to capture small fish. Before striking, they draw in their neck and crouch down so low that their belly often touches the water. Their foraging style is generally more jittery and active than some other herons, chasing after fish with wings flapping or pirouetting with sharps stops and turns. Similar to Reddish Egrets, they also bend forward and push their wings over their head to entice fish to enter the shade provided by their wings.

Nesting

Nest Placement

Tricolored Herons are colonial nesters, often nesting with other herons and egrets. They typically breed on islands or higher ground with dense vegetation. Males tend to pick a spot in a shady and dense tree or shrub up to 13 feet above the ground or water.

Nest Description

The male collects large twigs and builds a loose platform before pairing. After pairing the male brings more twigs to the female, who rearranges them into a bulky platform. Some females line the nest with finer twigs and cordgrass.

Nesting Facts

Behavior

Tricolored Herons gracefully walk through wetlands as other herons do, but they also run after fish with sharp turns and stops, balancing with their wings. They tend to forage alone or at the edge of flocks of wading birds. Although they are solitary foragers, they nest in colonies often with other herons and egrets. At the colony males are aggressive toward all individuals that come near the nest site, but gradually let a female enter during courtship. Aggressive posturing includes calling, stretching the neck straight up, fluffing up the crest feathers, holding the wings below and away from the body, fighting and jabbing in midair, and shaking twigs. Males court females near the nest site. Males bow down, grab a twig, and then stretch the head straight up while snapping the bill. They also fly in a circle around the nest territory, making deep wingbeats that create a deep whomp sound. Once paired, the arriving bird often greets the other with feathers raised, pointing its bill skyward and then down at the nest while passing a twig to its mate. Pairs form a monogamous bond for the breeding season and perhaps longer.

Conservation

Tricolored Herons are common and their populations were stable from 1966 to 2015, according to the North American Breeding Bird Survey. The 2002 North American Waterbird Conservation Plan estimates a U.S. breeding population of fewer than 194,000 birds. It lists the Tricolored Heron as a species of high conservation concern. In 2015,Partners in Flight ranked them an 11 out of 20 on the Continental Concern Score, which means it is not on the Watch List and is a species of low conservation concern. Discrepancies in population estimates could be due to survey method and difficulty in detecting this dark heron by aerial surveys. The status of Tricolored Herons varies by state and region. In the central Everglades in Florida, the number of breeding pairs decreased by 75% from 1996 to 2002 and 2007 to 2010, prompting the Florida Fish and Wildlife Conservation Commission to list the Tricolored Heron as state threatened. But in several mid-Atlantic states populations increased from 1940 to 1970 after the construction of intracoastal waterways that provided more nesting habitat. Reduced flows of freshwater in the Everglades are likely responsible for population declines there. In other areas habitat loss may be contributing to declines, but increases in aquaculture farming along the coast can also place Tricolored Herons at greater risk of being shot or falling victim to bird repelling techniques. Still in other areas, increases in artificial wetland habitat through dredging may benefit Tricolored Herons by providing additional nesting locations.

Credits

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Frederick, Peter C. (2013). Tricolored Heron (Egretta tricolor), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, USA.

Lutmerding, J. A. and A. S. Love (2016). Longevity records of North American birds. Version 2016.1. Patuxent Wildlife Research Center, Bird Banding Laboratory, Laurel, MD, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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