The email was from a friend, Tom: a sorta-kinda birder, someone more serious about photography than identification. “This can’t be what I think it is, can it?” he asked, referring to an attached photo. “It sure looks like a Limpkin, but the field guides say they’re not found outside of central Florida, and I took this near Baton Rouge, Louisiana.”
Field guides are always in flux because bird populations are dynamic. But few species have rendered even the most recently updated app obsolete as quickly as have Limpkins—those odd, not-quite-rails of deep swamps and wetlands, their dark brown plumage spangled with silvery white, named for their ostensibly limping gait. While Limpkins are widespread from southern Mexico and the Caribbean through much of Central and South America, in the United States they were long restricted to central and southern Florida—as my friend correctly thought. Yet Tom’s ID was spot-on. What he didn’t realize is that he was witnessing a small part of one of the most extraordinarily rapid range expansions ever made by any native North American bird.
A century ago, Limpkin sightings were so rare north of Florida that the handful in Georgia and of scattered vagrants farther north were considered noteworthy. The waders were by and large a Florida specialty because that’s where their primary food, the Florida apple snail, was found. Limpkins themselves were considered a good meal, leading to a dramatic population decline. “The flesh of the limpkin is much esteemed,” ornithologist Arthur C. Bent lamented in 1926, noting that they had “practically disappeared from all regions within easy reach of civilization.” A 1932 review of Florida’s birdlife said that Limpkins, which had been abundant, were scarce or absent in many former strongholds in the wake of the dredging and draining of the state’s wetlands. Their numbers rebounded with protection and habitat restoration, but Limpkins remained tightly wedded to Florida and the range of its native apple snail for many decades to follow.
Within the past decade, this once uncommon, range-limited, generally nonmigratory species has undergone an astounding change in fortune. Its ballooning population rapidly colonized westward to Louisiana and deep into Texas, and then exploded outward in unprecedented waves of seasonal vagrancy that have carried these birds of the Deep South as far north as eastern Canada during warmer months. At first it seemed like a onetime phenomenon, the kind of unusual sighting that would be broadcast on rare bird alerts and draw dozens or hundreds of birders to see it. But it now appears it could be the new annual norm, one that has sparked a sudden rush of interest in a species that was largely overlooked for a long time—and has folks wondering what Limpkins will do next.
I
f Limpkins were children, they’d be labeled fussy eaters. It’s not that they can eat only one thing, just that they very much prefer to, thank you. Limpkins will take various smaller snails and freshwater mussels, and even on occasion lizards, frogs, and crayfish. Yet they’re so focused on apple snails that their long, decurved bills have a peculiar, slightly sideways bend to the right at the tip of the lower mandible that helps them pry open the right-handed curve of the shells.
But there are apple snails, and there are apple snails. By the late 20th century, several kinds of invasive apple snails were beginning to show up in Florida, most ominously the island apple snail, which is native to southern South America. Most likely introduced through imports sold to aquarium hobbyists, it’s also known as the giant apple snail, and it’s a whopper: up to five or six inches in diameter and three or four times heavier than Florida’s native apple snail. It’s also wildly more fecund, producing up to 2,000 eggs every week or two, instead of the native’s 30; those eggs, bubble-gum pink and laid above the water’s surface, are protected by a neurotoxin potent enough to cause skin irritation in humans if handled. What’s more, island apple snails breed year-round, are able to breathe air when the water levels drop, and tolerate a much wider range of conditions. By the early 2000s the invasive mollusk was taking over wetlands across the state at densities much higher than the native species.
The appearance of these giant invasive snails caused a conservation panic, because the Florida apple snail was also the sole food of the endangered Snail Kite. The raptor’s population had crashed to fewer than 800 individuals in 2008 as drought took a toll on native snails. The invasives were so large and heavy that kites, especially young ones, had trouble holding, carrying, and opening them—a difficulty that experts warned could spell local extinction for the highly specialized species. Yet in barely 10 years the birds evolved longer and heavier legs, bigger body mass, and more robust beaks to handle the beefy new food source. What had seemed a disaster became a bonanza. Fed by the new snails, bigger kites flourished, and the population spiked to roughly 3,000 adults in Florida by 2023.
With all the attention focused on Snail Kites, few people were thinking about Limpkins—which isn’t anything new. Limpkins, as they say, get no respect. One of the challenges I ran into while reporting this story is the apparent lack of actual Limpkin experts; the absence of almost any peer-reviewed research is a reflection on what, apparently, has long been considered a rather boring species. The Limpkin account in the online Birds of the World—usually the most authoritative and up-to-date resource for North American birds—hasn’t been revised since 2002, perhaps because until recently there wasn’t much new to be said.
But just as the new snails were ushering in salad days for Snail Kites, the same thing was happening under the radar for Limpkins, which seemingly had no problem with the larger prey. As island apple snails expanded in number, Limpkins did, too. Propelled by a swelling Florida population, Limpkins began heading for the far horizon, following the invasive snails out of the Panhandle.
W
hile Limpkins had occasionally strayed from Florida in the past, showing up as far afield as Nova Scotia, they had never made it to Louisiana. So when Christmas Bird Count (CBC) participants found four Limpkins there in December 2017, it caught the attention of Robert C. Dobbs, nongame avian ecologist for the Louisiana Department of Wildlife and Fisheries.
“Birders were obviously excited, but it was boat-accessible only, really hard to get to and few, if any, folks that I recall actually tried to chase them down,” Dobbs says. But a few weeks later, he says, two Limpkins were spotted in a marsh near Houma, just off the road and easy to observe, and more than 100 birders flooded in to add a new species to their state lists. What’s more, the birds immediately settled down and produced the state’s first breeding record that spring.
By 2021 the Limpkin had become such a ubiquitous, ho-hum presence east of the Atchafalaya River that the state records committee, which tracks rare bird sightings in Louisiana, took it off the review list. It was perhaps the fastest a bird has gone from newly added to the official Louisiana list to a collective shrug, Dobbs says. “And then in 2022, they just seemed to really blitzkrieg the western part of the state,” he says. Even when birders weren’t seeking them out, like when they were conducting CBCs, Limpkins showed up. In that same time frame, Limpkins also staked a claim in Texas, nesting outside Houston and popping up along the major river systems like the Trinity and Brazos up toward Dallas and all the way north to Oklahoma.
Hot Limpkin Summer was followed by Bonkers Limpkin Winter.
With Limpkins beginning to breed in Gulf states beyond Florida, and their numbers steadily growing across the South, eBird trend data suggest that the U.S. population increased by more than 50 percent between 2012 and 2022. Maybe it was the pressure of all those extra birds, but suddenly the cork popped, and the region wasn’t big enough for them anymore. The pace and intensity of their vagrancy, which had already been increasing, ratcheted up. In 2021, Limpkins were spotted for the first time in Arkansas, in Tennessee, on the Maryland–West Virginia border—and in Minnesota, a real mind-blower at a solid 1,500 miles from central Florida.
Then, in 2022, Limpkins simply exploded across the eastern two-thirds of North America. Birders reported hundreds of sightings in a vast region from tidewater Virginia in the east, north to New York—and within sight of birders in Ontario—west to Michigan and Wisconsin, and south through eastern Iowa, Nebraska, Kansas, and Oklahoma down to Texas. “Hot Limpkin Summer,” birders dubbed it, as state after state—nine in all—racked up records for first sightings week after week across the country. But it didn’t end. Hot Limpkin Summer was followed by Bonkers Limpkin Winter. And 2023 saw even more of the brown swamp-dwellers showing up, this time as far north as southern Ontario (a provincial first) and Nova Scotia (a third record) and west into Colorado (also a first, along with inaugural Limpkins in New Jersey and Pennsylvania). Limpkins are making leaps and bounds largely in the summer, likely because warmer conditions suit the subtropical birds, while the winter records from up north are generally Limpkins that showed up before the mercury dropped and tried to overwinter.
Nate Swick, education and digital content coordinator for the American Birding Association, has been trying to keep up with it all, though he admits it’s become a blur. Swick produces the ABA’s weekly online summary of rare bird sightings across North America, and for a while it seemed as though it was all Limpkins, all the time. “It’s been quite the absolutely wild phenomenon, and an ongoing one,” he says. “I can’t think of another bird that has gone from red-letter rarity to just passé in such a short amount of time. Even Great-tailed Grackles were not like this, or White-winged Doves,” two species that also expanded their range tremendously, but over the course of decades. It took western House Finches half a century to expand across the Great Plains after being released in New York in 1939. With Limpkins, “it’s been almost instantaneous, and it’s been wild to watch,” says Swick.
While Limpkins haven’t crossed any new borders so far this year, Swick ventured some predictions on the states that might be next. The birds have flirted with the South Dakota line, and he thinks New Mexico is primed for its moment in the spotlight. Maybe even Québec, he says, if Limpkins get in a late summer run up along the Great Lakes.
“It hardly feels appropriate to refer to Limpkins as ‘vagrants’ in many regions of the continent now,” says Tim Healy, a New York birder who has been keeping close tabs on the Limpkin’s movements, and to whom I am grateful for his careful tabulation of all these records. He also points out that in 2023, every state and province that had ever hosted a Limpkin in the past had at least one again, evidence of how both pervasive and sustained this phenomenon had become.
L
impkins aren’t moving willy-nilly. As Swick and others have pointed out, they seem to be using major river systems like the Mississippi as their route north into the continental interior. And while island apple snails may have ignited the Limpkin boom, they are not its only fuel. The birds have expanded beyond the cold-sensitive island apple snail’s range, which currently does not—and is not projected to—extend farther north than North Carolina.
While island apple snails may have ignited the Limpkin boom, they are not its only fuel.
While apple snails are their staple, Limpkins will eat pretty much anything with a shell, and it turns out lots of food is available in northern rivers and wetlands—including a plethora of invasive mollusks that may be providing ready-made meals as they go. These include the Chinese mystery snail, a small apple snail lookalike that’s common in waterways in southern Canada and the northern United States, and Asian golden or basket clams, now abundant in rivers and streams across the country. New York’s first Limpkin, which showed up in November 2022 along the Niagara River, was feeding on brown-lipped snails, a species native to Europe but now common in the Northeast.
Invasive snails might be a boon for Limpkins and kites, but no one sees the incursion as a net ecological gain. Research shows that island apple snails, for instance, have an outsize negative effect on wetland vegetation compared with native plants—perhaps not surprising given their much greater size. Cayla Morningstar, a U.S. Geological Survey biologist, says that while the snails will eat harmful invasive plants like hydrilla and water hyacinth, they aren’t picky: “They eat any aquatic plant really that’s around; they can decimate entire areas of plants.” One study found that the snails caused a so-called phase shift in a wetland, changing what had been clear water dominated by submerged aquatic vegetation to open, turbid water dominated by algae, dramatically reducing its biodiversity.
What’s more, there are concerns they could pose a serious agricultural problem, as other introduced apple snails do on rice fields in parts of Asia. In Louisiana and Texas, farmers drill-plant rice on dry land instead of flooded fields, which seems to be minimizing problems with that crop. But invasives are clogging the traps that farmers use to harvest crawfish from flooded fields that are often rotated between rice and crawfish crops. “The amount that they’re pulling out of these crawfish traps—it’s pretty catastrophic,” Morningstar told me, sharing photos of hundreds of pounds of bagged snails. So far, there seem to be few control options in crawfish ponds other than trying to prevent the snails from moving into uninvaded areas.
Could Limpkins provide some measure of containment? “When we first saw Limpkins, we were all, like, ‘Hey, yeah, this could be a natural biocontrol,’ without having any idea of whether that was actually a biologically feasible scenario or not,” Dobbs says. Now enough Limpkins are nesting in Louisiana that they could investigate that question.
On the flip side, Limpkins breeding well north of the island apple snail’s range may pose a new conservation conflict. As many birders have observed, Limpkins like to eat freshwater mussels, which are the most endangered group of North American wildlife; 65 percent of the roughly 300 species are considered imperiled, thanks to centuries of water pollution and damming. Dobbs is aware of at least one anecdotal account of a Limpkin preying on a state-listed mussel species of conservation concern in Louisiana. And while the larger, slower rivers and swamps that Limpkins prefer have fewer of the rarest species, if the birds become more regular in smaller, upland waterways that hold many of the listed species, they may become an issue.
With lots of potential Limpkin food far from their original Florida home, some people who see the ease with which the birds occupied hundreds of miles of new breeding territory along the Gulf have started wondering how long it may be until they try breeding in the north. There has always been a suspicion that some Limpkins in northern Florida, especially females, undertake seasonal movements south at the end of the breeding season, and there may even be an annual migration between Florida and Cuba. If the DNA for such small migrations is already baked in, what are the chances they might begin to make bigger leaps, flying north to nest and then retreating south again in autumn?
F
ar from being a boring bird, the Limpkin is a species crying out for some serious scientific study. Dobbs says he kicks himself for not starting a rigorous effort as soon as Limpkins showed up in Louisiana, mapping their expansion and population growth. But another part of this story may yet unfold. Dobbs points out that when two different species of invasive apple snails were introduced to the Pacific coast of Mexico in the late 20th century, Limpkins started moving rapidly north to exploit them—followed, 5 or 10 years later, by Snail Kites: “Thinking about the timeline, maybe we should be looking for Snail Kites here right now.”
Tyler Beck isn’t so sure. He’s the wetland avian habitat specialist for the Florida Fish and Wildlife Conservation Commission and oversees its Snail Kite work. Researchers have found that kites have expanded their range roughly 175 miles north from their previous limit in the Kissimmee River Valley into places like Paynes Prairie south of Gainesville, an area where the raptors were known to have nested nearly 60 years ago. Beck says that while he could envision them reclaiming areas like Big Bend at the juncture of the Panhandle where they nested historically, “I don’t think we’re going to see them into Arkansas or anything like that.”
For one thing, kites need more than just apple snails; their nesting requirements are more finicky than a Limpkin’s. Snail Kites require healthy, shallow wetlands with isolated patches of vegetation that allow them aerial access from above to tend to their young. “I think they could potentially expand their range somewhat more,” Beck says, “but I don’t think it’s going to be to the extent that Limpkins have.”
He may be right, but the kites will have the final say. In April, North Carolina recorded its third sighting, and Tennessee recorded its first in May. In July one showed up for the first time in—wait for it—Louisiana. If there’s a lesson in all this, it’s that we underestimate the adaptability and dynamism of birds again and again. Many species, for instance, are responding to a warming climate by shifting their ranges, with Roseate Spoonbills and Wood Storks finding new homes north of Florida. Endangered Southwestern Willow Flycatchers have undergone genetic changes that make them more tolerant to the wetter and more humid conditions their Southern California population is experiencing. This resilience doesn’t mean we can ignore habitat destruction, the spread of invasive species, and other threats, but it does provide hope that birds can survive—and even thrive—amid the changes, especially with our help.
Beck certainly finds the Limpkin turnaround impressive. Until recently, Florida classified them as a species of special concern and, at one point before the invasive snail appeared, considered beefing up their level of protection to threatened. But governmental gears move slowly, and by the time Beck was reviewing the proposal to list them as threatened, he was “seeing them everywhere and seeing reports of them in crazy places,” he says. “And I’m, like, I think I’m wasting my time reviewing this because I think they’ve totally turned the page on this. We have the opposite story now.”
Florida delisted Limpkins in 2017. It’s not every potentially threatened bird that essentially saves itself, even with an invasive assist.
This story originally ran in the Fall 2024 issue. To receive our print magazine, become a member by making a donation today.
