By Renée Wilson, Audubon Florida
Environmental conditions are changing in the Everglades. This is especially the case in Florida Bay, where 90% of Florida’s roseate spoonbills once raised their young. But rising water levels are pushing roseate spoonbills to nest farther inland and farther north.
Audubon has studied roseate spoonbills since 1934. Because the spoonbills are considered an indicator of overall Everglades and Florida Bay health, Audubon staff at the Everglades Science Center in Tavernier continually monitor their location and nesting success using bird banding, GPS tags and camera traps. While the issues cannot be addressed by science alone, sharing this data with advocates and policymakers is the key to a more resilient future for Florida’s birds.
Rising seas
Forty years ago, only a handful of roseate spoonbills made their nests anywhere but Florida Bay — this species has had a clear relationship with water conditions in the River of Grass for centuries. But deeper waters hinder their foraging efficiency, threatening the health of their chicks.
Each summer, fresh water from rainfall flows across the Florida mainland, delivering nutrients to and raising water levels in Florida Bay. As the winter “dry” season sets in, typically by the end of January, levels would historically fall to better foraging depths for roseate spoonbills to find food.
Shallow waters concentrate fishy prey well within reach of their snapping, spoon-shaped bill, making it possible to catch enough food to raise a family before spring rains return and raise water levels again.
For roseate spoonbills to maintain a stable population, each nest must fledge at least one chick. However, water levels in South Florida have been rising steadily — since 2000, water levels have risen nearly five inches.
“Spoonbills require water depths no greater than 20 cm to forage effectively due to their body size,” explains Alexander Blochel, senior biologist at the Everglades Science Center. “However, their optimum water level is around 13 cm, as this is when the fish they prey on become easier to catch,” he added.
How birds are affected
Staff recorded 1,250 nesting pairs of spoonbills in Florida Bay in 1979, which dropped precipitously to 600 nesting pairs by 1989. These numbers bumped up slightly in the early 1990s but eventually declined to an abysmal 400 nesting pairs by 1994. By 2010, fewer than 100 nesting pairs of this emblematic species occurred in Florida Bay.
While these numbers seem bleak, many spoonbills have moved to different foraging and breeding areas around Florida and beyond and are doing quite well. For example, Audubon Florida staff monitoring the Richard T. Paul Alafia Bank Bird Sanctuary in the Tampa Bay region, which is leased from and managed in collaboration with the Mosaic Company and Port Tampa Bay, counted nearly 100 roseate spoonbill chicks that fledged from approximately 50-75 nests nearby.
To combat these challenges, Audubon works to protect a variety of habitats for roseate spoonbills and other vulnerable wading bird species as climate change and other threats affect their nesting, breeding and feeding grounds. Audubon also continues to develop innovative strategies for understanding how climate change and other threats impact Florida’s birds. Our data informs policies and projects aimed at protecting vulnerable species like roseate spoonbills to ensure their survival for future generations.
By 2028, Audubon will work with policymakers at the local, state, national and international levels to meet the goals established in our policy agenda to advance and fund conservation and climate initiatives.
Renée Wilson is senior communications coordinator for Audubon Florida. This piece was originally published at https://www.audubon.org/florida/news/are-rising-sea-levels-impacting-roseate-spoonbills-florida-bay. Banner image: A roseate spoonbill forages near the mangroves in the Everglades. (Photo: Renée Wilson/Audubon Florida).
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