Reddish Egrets in Florida Bay Facing Uncertain Future

As the sun rises over Florida Bay, so do thousands of birds that rely on its shallow waters and mudflats to forage for fish or invertebrates. On a typical day, you may see Ospreys, White Ibises, and Roseate Spoonbills, to name a few. However, if you are lucky, you may spot a more elusive resident lurking in the mangroves or prancing in the shallows: a Reddish Egret. 

Considered North America’s rarest heron, the most recent IUCN Red List Assessment (2020) estimates the Reddish Egret to have a global population of just 5,000-9,999 mature individuals. Not surprisingly, research on this species is limited and ongoing. The biologists at the Audubon Everglades Research Station (AERS) in Tavernier, Florida are determined to understand these mysterious birds better. To achieve this, the wading bird team can often be found climbing mangroves and surveying remote parts of the Everglades as they look for their nests across 60 different Florida Keys. 

Distribution  

Reddish Egrets are generally found year-round in southern Florida, Cuba, the Bahamas, and along the coasts of Texas and Mexico. Despite their widespread range, they remain rare sights due to their low numbers and patchy population distribution. As a habitat specialist, the Reddish Egret is restricted to undisturbed coastal saline habitats such as lagoons, beaches, marshes, islands, and tidal flats for nesting and foraging. To forage successfully, they seek out water levels ranging from 5 cm to 20 cm deep. Their foraging strategy—capturing fish while leaping with their wings held above their head—is most effective in shallow waters.

Many of Florida’s Reddish Egrets reside in Florida Bay, a lagoon that makes up one-third of Everglades National Park and is located at the very southern tip of the Florida mainland, situated between the Everglades and the Florida Keys. It is made up of mudflats exposed at low tide, intermixed with pockets of deeper water and seagrass beds. 

Florida Bay receives fresh water flowing down through the Everglades, mixing with tidal saltwater from the Gulf and the Atlantic, creating a nutrient-rich lagoon that supports biodiversity hotspots. Combined with numerous untouched, protective mangrove islands, the bay is an ideal place for a Reddish Egret to call home and an excellent location for the wading bird team to focus their research efforts.

Life History and Breeding

The highest concentration of Reddish Egret breeding pairs occurs along the Gulf Coast, where an estimated 2,820 pairs breed across eastern Mexico, Texas, parts of Louisiana and Alabama, and southern Florida. Nest site selection is primarily influenced by proximity to suitable foraging habitat, which they return to each year. As a result, breeding pairs nest in the same general geographic area across years, although they do not necessarily return to the same site. Their nests are found in variable locations, including rocky scrapes, mangrove trees, and marsh grasses.

The Audubon Everglades Research Station tracks Reddish Egret nests from the building stage up until the fledglings leave the colony, which is roughly a four-month-long process.

Month 1: Reddish Egrets lay and incubate eggs. They have an average clutch size of 3.1 eggs and an incubation period of 26-29 days.

Month 2: After hatching, young remain in the nest for about 24 days. During this time, they lose their down coating, grow regular feathers, and develop scales on their legs. By the end of this month, they are walking and exploring the branches around their nest.

Month 3: Reddish Egrets start learning to fly about 45 days after hatching. They remain in the colony while they refine their flying skills and continue to rely on mom and dad for food. 65 days after hatching, Reddish Egrets are fully independent, and young of the year can be seen foraging for themselves.

Month 4: Reddish Egrets depart their natal colony at 12 weeks old.

Reddish Egrets become sexually mature at three to four years of age. They have delayed sexual maturity compared to most herons and egrets, many of which reproduce at one to two years old. Research suggests they live up to 12 years in the wild.

Migration

Research on Reddish Egret migration is limited and conflicting; however, current data suggest that migratory behavior varies across their geographic range. In areas where there is ample space and foraging habitat available year-round, Reddish Egrets rarely migrate. Comparatively, in areas where resources are limited seasonally, Reddish Egrets are categorized as a partial or semi-migratory species. This means that only a portion of the population migrates, with resident individuals maintaining a physiological, social, or environmental advantage that allows them to remain year-round in their territory. Partial migration is a common evolutionary strategy for species that live in unpredictable habitats, such as coastal wetlands.

Satellite tracking data and band resight reports have shown that non-resident Reddish Egrets fall into one of two groups: short-distance and long-distance migrants. Unlike the Canada Goose or Sandhill Crane, migrating Reddish Egrets do not fly in large groups across established routes. Migrating birds settle where they can establish personal territories, resulting in routes that seemingly end at random locations with some overlap. There are a handful of known spots where Reddish Egrets flock in the winter, such as Tamaulipas, Mexico; however, for the most part, wintering locations vary between individuals. By studying where and when migrant birds settle for winter, biologists can map the distribution of periodically available, resource-rich areas.

Audubon's wading bird team primarily focuses their studies on Reddish Egret nesting, as the colonies in Florida are not currently known to migrate. The Reddish Egrets in Texas, however, provide a good example of partial migration strategies. The Laguna Madre, a large, hypersaline lagoon in Texas, boasts the largest population of breeding Reddish Egrets in the world. Short-distance migrants typically travel from the upper Laguna Madre to the lower Laguna Madre and vice versa. Long-distance migrants, however, typically settle either individually or in small groups outside of the state. 

Below is a map showing the winter locations of long-distance migrants from the Laguna Madre reddish egret colony. Note the multi-directional dispersal.

Conservation Concern

A 2022 assessment identified climate change and coastal engineering and development as the top threats facing Reddish Egrets worldwide. Across most of its range, sea level rise would eliminate valuable foraging habitat due to erosion, wind, and inundation. Furthermore, increased storm frequency and intensity physically damage nesting habitat, taking years to reverse. 

While individual flighted Reddish Egrets tend to survive intense weather events, hurricane season aligns with the end of the breeding season. Consequently, recently hatched nestlings or young birds learning to fly cannot escape and frequently do not survive these storms. Increased coastal infrastructure results in direct loss or alteration of nesting and foraging habitat. Activities such as dredging, shoreline armoring, shipping, and construction change the hydrology of the landscape, release contaminants, and decrease water quality of the wetlands Reddish Egrets rely on. Unlike some of the effects from climate change, coastal development and engineering irreversibly damage their habitat.

Conclusion

The Reddish Egret, with its low population numbers and stealthy behaviors, continues to keep researchers on their toes. Researchers believe that more satellite tracking studies are essential to understand their population dynamics and guide best conservation practices. Amongst all of the uncertainty, however, birders and biologists alike know one thing: if a Reddish Egret graces you with its presence, it is going to be a great day.

References

1. BirdLife International. Egretta rufescens, Reddish Egret. The IUCN Red List of Threatened Species; 2020. Report No.: T22696916A154076472. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T22696916A154076472.en
2. Cornell Lab of Ornithology. Reddish Egret Range Map. All About Birds Cornell Lab of Ornithology; 2025. https://www.allaboutbirds.org/guide/Reddish_Egret/maps-range
3. Wilson TE, Wheeler J, Green MC, Palacios E, editors. Reddish Egret (Egretta rufescens) Conservation Action Plan. 1st Reddish Egret Conservation Planning Workshop; 2012 Oct; Corpus Christi, TX. Reddish Egret International Working Group; 2014. https://www.conservationstandards.org/wp-content/uploads/2020/10/REEG_plan_final_single-2.pdf
4. Hill A, Green MC. Reddish egret (Egretta rufescens) in the lower Florida Keys. J. of Heron Biol. and Conservation. 2011;1(6):1-5. https://www.heronconservation.org/media/JHBC/vol01/01_06_Hill_and_Green.pdf
5. Collins SA, Selman W, Green MC, Strong WT. Reproductive ecology and nest success of reddish egrets (Egretta rufescens) on a natural marsh island in southwestern Louisiana, USA. Waterbirds. 2021;44(1)1-12. https://doi.org/10.1675/063.044.0101
6. Green MC, Demarest DW, Tarbox BC, Cox A, Franco JG, Torres SN, Stone KL, Vermillion WG, (editors). Conservation Action Plan for the Reddish Egret (Egretta rufescens), 2022 Update. 2nd-4th Reddish Egret Conservation Planning Workshops; 2018; Merida, MX. 2019; Cameron, LA. 2019; Cedar Key, FL. Reddish Egret International Working Group; 2022. Conservation-Action-Plan-for-the-Reddish-Egret-2022-update.pdf
7. Cox WA, et al. Distribution and population status of nesting reddish egrets (Egretta rufescens) in Florida. Florida Field Naturalist. 2019;47(1):1-14.
   https://digitalcommons.usf.edu/ffn/vol47/iss1/1
8. Koczur LM, Ballard BM, Green MC, Hewitt DG, Henke SE. Breeding ecology and habitat use of North America’s rarest Ardeidae: the reddish egret Egretta rufescens. Avian Conservation and Ecology. 2018;13(2):10. https://doi.org/10.5751/ACE-01258-130210
9. Reddish Egret (Egretta rufescens). Texas Parks and Wildlife Department; 2004. https://tpwd.texas.gov/huntwild/wild/species/reddishegret/
10. Koczur LM, Ballard BM. Drivers of partial migration in the reddish egret Egretta rufescens. J. of Avian Biol. 2024;2024(1-2):e03133. https://doi.org/10.1111/jav.03133
11. Basille M. Partial migration of a large wading bird in a highly unpredictable environment. Mathieu Bastille Lab at University of Florida; 2018 Aug 9. https://mablab.org/talk/picardi_2018_neworleans/
12. Picardi S, Frederick PC, Borkhataria RR, Basille M. Partial migration in a subtropical wading bird in the southeastern United States. Ecosphere. 2020;11(2):e03054. https://doi.org/10.1002/ecs2.3054
13. Geary B, Green MC, Ballard BM. Movements and survival of juvenile reddish egrets Egretta rufescens on the Gulf of Mexico coast. Endang Species Res. 2015;28(2):123-133. doi:10.3354/esr00682