By: Riley Gonzalez
Environmental Communicator at the University of Florida Thompson Earth Systems Institute
Published May 2022
Perhaps one of the most emblematic species of Florida's changing environment is the endangered Everglades snail kite.
In the Central and South Florida wetlands, the snail kite can be seen gliding over the Everglades sawgrass on the hunt for its next meal. While its striking red eyes and sharply curved bill may make the bird appear frightening to some, there's no need to fear, the snail kite’s diet mainly consists of just one thing — apple snails. Many animals rely on a wide-ranging diet to ensure adaptability and survival, but the snail kite is a case of specialization to the extreme. Even so, our changing planet has allowed these birds of prey to find an abundance of food outside their normal range of habitat. In fact, the snail kite was recently observed nesting north of Orlando for the first time in 98 years.
Hurricanes, changing water levels, and habitat degradation can impact the bird's nomadic behavior, making it a perfect example of how wildlife can help us take the pulse of our planetary health.
Scientists have warned us of the oncoming dangers associated with climate change and human impact on the environment. Current predictions estimate that in South Florida the sea level will rise 11 inches by 2040. Hurricanes, another major issue for the Sunshine State, are predicted to intensify in the coming years. Although these changes are already unfolding, many people are fortunate enough to not feel the effects in their day-to-day lives.
Meanwhile, behaviors are changing briskly within the animal kingdom. Studying wildlife behaviors such as species distribution, breeding ranges, and migration routes can help scientists understand the ways our planet is transforming. Animals are constantly interacting with their environment to fulfill their needs, so observing them helps us understand which locations are struggling and why. While there are numerous different scientific tools used to collect ecological data, sometimes the best indicators of environmental health are the animals themselves, commonly referred to as indicator species.
If you spend time at Paynes Prairie, you may have noticed the recent addition of snail kites to the area's booming bird population. Over 300 species of birds frequent the park, but the snail kite was not a typical visitor until the past few years. Record-breaking storms and hurricanes such as Irma, which made its way up the Florida peninsula in 2017, brought high waters to the prairie basins in North Florida.
The extra rain increased prairie water levels significantly, creating an ideal habitat for invasive apple snails, which are larger than Florida's native apple snails, yet just as tasty to the snail kites. While invasive species are usually thought of as nothing but trouble, the invasive apple snail's growing population has lured hungry snail kites to the north. This twist of events brought on by Hurricane Irma appears to be a win for the snail kites, but their victory may not last.
“The problem with snail kites relying on invasive apple snails is that invasive species can have a kind of boom-bust population model," explained Andrew Kratter, the ornithology collections manager at the Florida Museum of Natural History. "They come in and their population booms like crazy and then eventually something counteracts that: competition, parasitism, something usually knocks it back.”
In other words, the birds may be enjoying their feast of snails now, but the offer is only valid while supplies last.
The expansion of snail kites to more northern parts of Florida is not necessarily a problem. This kind of dispersal can actually be beneficial for gene flow and population growth. Although snail kite populations are rebounding in the North, their departure from southern Florida reflects problems in the area. In the past, Lake Okeechobee has hosted over 100 snail kite nests, but in 2018 and 2019 there were none.
Florida biologists have carefully studied the snail kite for decades and observed an undeniable relationship between water levels and the bird's population numbers. The rate of successful nesting has dipped as low as 17% in drought years such as 1974, and on the reverse, risen close to 90% during years with optimal water conditions.
The complete absence of snail kites from Lake Okeechobee is a warning sign that water management in the area is struggling. In Alachua County, storm waters once helped create an ideal habitat for snail kites and apple snails, but a decrease in rain now has water levels lowering once again, and scientists are concerned about how the species will respond.
“There's a long history of knowing that water levels closely affect snail kite survival, reproduction, and movement," said Ellen Robertson, a postdoctoral researcher of wildlife and climate issues at Oklahoma State University. "Precipitation events are projected to get more extreme, through extreme flooding and extreme droughts, which will strongly affect snail kites.”
The birds' population numbers have fluctuated a lot — reaching dramatic lows in the 70s largely due to human development encroaching on wetland habitats. Then, conservation efforts helped them stabilize in the early 90s. Soon after that, their population took another dive due to further habitat degradation and periodic drought from 1996 to 2008.
“We can take the temperature, or we can measure the sea level, but we don't know how that's going to affect biology. One of the easiest ways to know what's going on is to go out and see what's happening to birds.”
The snail kite’s story can tell us a lot about what's going on in Florida’s environment. As the Everglades water woes continue even in the midst of large-scale restoration efforts, the snail kite still struggles to maintain a stable population in South Florida. And in North Florida, snail kite populations are recovering again thanks to an invasive species of snail. But, as the prairies slowly drain, snail kite populations could go down again as quickly as they shot up.
“We can take the temperature, or we can measure the sea level, but we don't know how that's going to affect biology," Kratter said. "One of the easiest ways to know what's going on is to go out and see what's happening to birds.”
But the snail kite is just one example of an indicator species. Countless other species of birds, reptiles, mammals, and everything in between, can serve as bellwethers of changes in their environment just as the snail kite does.
And, anyone can play a role in furthering our understanding of wildlife and environmental issues. Apps such as iNaturalist have created a community of citizens and biologists working together to document and identify numerous species of plants, animals, and insects. Users can upload a photo of their specimen along with its location, and receive help identifying the species in order to further their knowledge about the local environment. In turn, many researchers, conservationists, and scientists use the data from iNaturalist to answer important questions about the environment.
A similar but more specialized app, eBird, allows birdwatchers to contribute to growing wildlife databases. For those interested in an even more hands-on approach, citizen science projects may be the way to go. Citizen science, also commonly referred to as community science, is when members of the public collaborate with scientists to collect and analyze data on the natural world. These projects can range from tracking butterfly migration to monitoring water conditions. Not only does participating in community science help further the public's understanding of environmental issues, but it also enables scientists to collect large amounts of data more efficiently.
No one can say for certain what is coming next for the Everglades snail kite, but any Floridian can play a role in tracking sightings of these birds, as well as their new favorite snack, the apple snail.
Endangered since 1967, the snail kite has fought hard to have a stable population, but still, they remain vulnerable to hydrological issues, temperature changes, and habitat degradation. The snail kite's growing population in the north has been great news for Alachua County birdwatchers, but prairie water levels are known to fluctuate significantly, and may not be able to host the species forever. Even with ideal wetland management, there's no telling what may happen to the snail kites' unreliable and invasive favorite food. Whether the snail kite extends its stay in Paynes Prairie or returns to the south, these birds are certainly a species worth keeping your eye on.
This story is part of the UF Thompson Earth Systems Institute's student-produced Earth to Florida newsletter that curates the state’s environmental news and explains what’s going on, why it matters and what we can do about it.
The University of Florida Thompson Earth Systems Institute is advancing communication and education of Earth systems science in a way that inspires Floridians to be effective stewards of our planet.
Credits:
Photography by Nick Wallis Written by Riley Gonzalez