birds in tree

Statewide Survey of Nesting Reddish Egrets

by Andrew Cox


Birds in tree
Photo by Anne Macias, BBRWS Photographer

The reddish egret is North America’s rarest (and coolest) heron, with an estimated global population size of 3,500-4,250 breeding pairs.  A coastal specialist that nests on islands in estuarine and marine waters, the species was extirpated from Florida in the early 20th century due to plume hunting.  It subsequently rebounded and can now be found nesting on the gulf coast from Cedar Key south to Marco Island, throughout the Florida Keys, and on the east coast at Merritt Island National Wildlife Refuge.  The rarity of the species and potential recent declines across its range have led FWC to partner with Audubon Florida and the Avian Research and Conservation Institute on a two-year project to identify the most important breeding locations, estimate the number of breeding pairs in Florida, and learn more about the species’ nest-site selection habits in Florida.

In 2015, we intensively sampled 12 breeding sites to assess the accuracy and precision of several survey techniques.  We also scouted extensively for nesting birds throughout the Florida Keys in preparation for the actual survey.  We found that detectability was an issue during ground-based counts with this dark-plumaged, sub-canopy nesting species.  We also documented substantial breeding asynchrony in Florida Bay, precluding the use of a commonly implemented counting method that requires all nesting pairs to be incubating eggs.  These results have helped us refine on our sampling strategy for the upcoming breeding season when we will implement the statewide survey.

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