Expanding at a Snail’s Pace

The Magee Limpkin feeding on a snail in the genus Pluerocera.

In early July 2019, a juvenile Limpkin turned up outside of Akron, Ohio, superseding the species’s most northerly US record from Maryland in June of 1971 by nearly 250 miles. News of the state record spread throughout the birding community, and by nightfall, a binocular-clad crowd had gathered around the suburban pond where the young bird was calmly feeding on snails. Reports soon flooded in that this was no isolated incident, either. Just a few days earlier, another bird had been seen in Mentor, Ohio. One month later, a third Limpkin was reported from Magee Marsh, and in mid-October, a fourth from Mentor’s Veteran Memorial Park.

Range Map of the Limpkin in North America (Source).

The Limpkin (Aramus guarauna) is the only member of its genus Aramus. Cross the long legs and serpentine neck of a heron with the skulking gait and plump body of a rail and you will have something that quite resembles a Limpkin. These brown and white birds are inhabitants of southern swamps from Florida to Central and South America where they specialize on apple snails (Pomacea sp.) and other freshwater mollusks. With such a specialized diet, it’s a small miracle that the Limpkin has survived the draining and dredging of its wetland habitat.  Limpkin population trends are poorly understood, but the species appears to be stable in Florida. Recent declines in the northern portion of its range may represent a contracting distribution, and historical records suggest the Limpkin once inhabited Mississippi, Texas, and much of Georgia. 

Sightings of Limpkins north of Florida and extreme southern Georgia are rare, but records of vagrant Limpkins reaching northern latitudes date back to 1950s when an injured bird was found in Nova Scotia, Canada. Sightings of Limpkins in northern latitudes are typically one-offs and are short-lived. The Magee Limpkin on the other hand, has been seen on and off for nearly five months. 

Ohio isn’t the only state in 2019 to see its first Limpkin record. In August, Illinois’ first confirmed Limpkin was spotted on a lake near the city of Olney. In 2017, Louisiana had its first Limpkin record when a group of four appeared in December. The following month, a pair successfully reproduced for the first time in the state. This represents breeding nearly 350 miles west of the nearest confirmed breeding record. Two years earlier, Georgia had its first state breeding record near Albany. Decade long surveys suggest that vagrant Limpkins have been turning up with increasing regularity since the early 2000s. Alabama, Georgia, and South Carolina have seen the bulk of these vagrants, but Limpkins have found their way to Maryland, Virginia, North Carolina, Tennessee, Mississippi, and now Louisiana, Illinois, and Ohio.  

A bird turning up outside of its natural range is nothing special. Major weather events like hurricanes can blow birds off course, landing them in states where they have rarely or never been recorded before. In 2013, a Brown Pelican, a native of the Atlantic, Pacific, and Gulf coasts, awed birders when it spent the summer along Lake Erie after being swept up by a low pressure system. It represents only the third record of a Brown Pelican in the entire state.

For recently fledged birds, migration has a steep learning curve. Juvenile Scissor-tailed Flycatchers follow their parents as they use visual, magnetic, and celestial cues to navigate. These internal compasses allow them to travel from the prairies of central North America to the southern Caribbean and back each year. During these travels, juveniles can often become disoriented, landing them well outside the usual range for their species. Migration is not all learned either. Sometimes, a genetic mutation can cause a bird's internal navigation system to go haywire. This may partially explain why scissor-tailed flycatchers (as well as many migratory species) occasionally deviate from their set migratory trajectory and have been sighted across North America from Alaska to Nova Scotia. 

Then there are the dispersers, which Joseph Grinnell described as “the exceptional individuals that go farthest away from the metropolis of the species; they do not belong to the ordinary mob that surges against the barrier, but are among those individuals that cross through or over the barrier.” Dispersers travel farther than 90% of the population and are responsible for the rapid colonization of human-introduced species like the European Starling and House Finch. How else would birds that rarely travel farther than 50 km in a lifetime colonize eastern North America from one, small founding population in just a few decades? 

Due to its exploratory nature, dispersal is a highly risky endeavor, and many birds do not survive their forays into unknown territory. In 2018, a juvenile Great Black Hawk, a species native to central and South America, was found in Maine. It represents the first and only record of a Great Black Hawk in the US. Just why this bird traveled from the tropics to the northern forests is a mystery. The hawk was able to sustain itself on a diet of gray squirrels throughout the summer, but as winter encroached, the tropically-adapted bird suffered severe frostbite and later died in a rehabilitation center.  

When successful, dispersal acts as a positive feedback loop for population growth. Lucrative years of reproduction increase the odds some juveniles will be genetically predisposed to wander. Establishment of new populations by a few lucky dispersers bypasses the slow expanse of home range leapfrog that most individuals employ to avoid inbreeding. Newly colonized habitats are not subject to the same limiting resources that stall population growth, allowing a rapid expansion of the species across a wide geographic area. 

So what is responsible for Ohio’s sudden Limpkin mini-invasion? Limpkins are non-migratory birds, and the first sighting in early July and August precede the hurricane season. Following sightings have not been linked with any major storm events. A single Limpkin might indicate a faulty navigation system, but mutations are rare events and are unlikely to account for the multiple Limpkin arrivals in northern states. Juvenile birds dispersing from their natal territories seem the most likely explanation.  

Range of the native Florida Apple Snail (Pomacea paludosa). (Howells 2006).

Limpkins are closely tied to the distribution of their primary prey, the Florida Apple Snail (Pomacea paludosa). Florida Apple Snails are the only native apple snail in the continental United States and make up over 70% of the Limpkin’s diet. Extending from peninsular Florida to the panhandle to the southern edge of Georgia, the Florida Apple Snail matches the distribution of the Limpkin almost perfectly. Extensive wetland loss during the 20th century greatly reduced the density of native apple snails and contributed to Limpkin population declines and local extinctions. Today, the Florida Apple Snail is considered an indicator species for successful wetland restoration. 

A large invasive Island Apple Snail from Arthur R. Marshall Loxahatchee National Wildlife Refuge in Florida.

In the late 70s, several species of non-native apple snail, including the Island Apple Snail (Pomacea maculata), became established in the US. Due to this snail’s greater size and fecundity, it has been able to outcompete the native Florida Apple Snail and has spread from North Carolina to Texas and across much of the southeastern US. 

Range of introduced Island Apple Snail (Pomacea maculata formerly P. insularum). (Byers 2013).

Invasive apple snails are veracious consumers of aquatic vegetation and pose a serious threat to agriculture and native ecosystems. As they consume algae, these snails bioaccumulate toxins that make them a health hazard to both humans and wildlife. Snail neurotoxins have been linked to Avian Vacuolar Myelinopathy (AVM), a lethal neurologic disease found in waterbirds and raptors. Snails can also carry rat lungworm (Angiostrongylus cantonensis), a parasite that causes eosinophilic meningitis in humans.

The invasive P. maculata is a tropical species, and while it is currently limited to a handfull of southern states, climate change is poised to expedite its invasion. On average, ten new P. maculata populations are discovered each year. Many biologists feared that the replacement of the native Florida Apple Snail with its larger, tropical relative would spell doom for apple snail specialists like the Limpkin and the endangered Florida Snail Kite (Rostrhamus sociabilis). These larger snails are harder for juvenile Snail Kites to handle, reducing their ability to forage and, in extreme cases, leading to starvation.

Snail Kite from Loxahatchee. 

What is truly remarkable, however, is that these hardy invasive snails seem to be supplementing the declining native P. paludosa and have jump started Limpkin and Snail Kite population growth. Both species have been documented readily feeding on invasive snails, and the latter may even be adapting to this novel prey (Snail Kites are increasing in body size and bill length). The introduction of P. maculata into novel watersheds has been directly linked with Limpkin range expansion. Limpkins were once exceedingly rare in Lake Seminole, Georgia, but following an unprecedented increase in P. maculata, some twenty birds were recorded in 2017. The first Limpkins to breed in Georgia did so within 5 km of the first P. maculata colony to become established in the state. Nearly all vagrant Limpkins in Georgia, South Carolina, and Alabama have turned up in watersheds that have known populations of invasive apple snails. 

So there we have it; a growing population in the stronghold of their range has allowed Limpkins to disperse into new regions of the country. Even the small, imperiled population of Snail Kites seems to be following this trend. In October, the first record of a juvenile Snail Kite was reported from Presque Isle, Pennsylvania. But will these birds survive in the northern latitudes? Ohio has no native or invasive apple snails. While we do have our own introduced species of large snail, the Chinese Mystery Snail (Bellamya chinensis), our winters can drop well below freezing for months on end. Establishment of a new Limpkin population in the northern US is extremely unlikely. The best we can hope for at the moment is that our vagrant birds will leave for the winter, and if Limpkin populations continue to grow and expand in the southern US, Limpkins may become increasingly common Ohio vagrants.

Limpkin from Loxahatchee feeding on a mollusk. 

References

Bloom, P. H., Scott, J. M., Papp, J. M., Thomas, S. E., & Kidd, J. W. (2011). Vagrant western Red-shouldered Hawks: origins, natal dispersal patterns, and survival. The Condor, 113(3), 538-546.

Byers, J. E., McDowell, W. G., Dodd, S. R., Haynie, R. S., Pintor, L. M., & Wilde, S. B. (2013). Climate and pH predict the potential range of the invasive apple snail (Pomacea insularum) in the southeastern United States. PLoS One, 8(2), e56812.

Cattau, C. E., Fletcher Jr, R. J., Kimball, R. T., Miller, C. W., & Kitchens, W. M. (2018). Rapid morphological change of a top predator with the invasion of a novel prey. Nature Ecology & Evolution, 2(1), 108–115. https://doi.org/10.1038/s41559-017-0378-1

Cattau, C. E., Martin, J., & Kitchens, W. M. (2010). Effects of an exotic prey species on a native specialist: Example of the snail kite. Biological Conservation, 143(2), 513–520. https://doi.org/10.1016/j.biocon.2009.11.022

Chaine, N. M., Allen, C. R., Fricke, K. A., Haak, D. M., Hellman, M. L., Kill, R. A., ... & Uden, D. R. (2012). Population estimate of Chinese mystery snail (Bellamya chinensis) in a Nebraska reservoir.

Cottam, C. (1936). Food of the limpkin. The Wilson Bulletin, 48(1), 11-13.

Dobbs, R. C., Carter, J., & Schulz, J. L. (2019). Limpkin, Aramus guarauna (L., 1766)(Gruiformes, Aramidae), extralimital breeding in Louisiana is associated with availability of the invasive Giant Apple Snail, Pomacea maculata Perry, 1810 (Caenogastropoda, Ampullariidae). Check List, 15, 497.

Greenwood, P. J., & Harvey, P. H. (1982). The natal and breeding dispersal of birds. Annual review of ecology and systematics, 13(1), 1-21.

Horgan, F. G., Stuart, A. M., & Kudavidanage, E. P. (2014). Impact of invasive apple snails on the functioning and services of natural and managed wetlands. Acta Oecologica, 54, 90-100.

Howells, R. G., Burlakova, L. E., Karatayev, A. Y., Marfurt, R. K., & Burks, R. L. (2006). Native and introduced Ampullariidae in North America: History, status, and ecology. Global advances in the ecology and management of golden apple snails, 73-112.

Kennedy, T. L. (2009). Current Population Trends of the Limpkin (Aramus guarauna) in Florida. Florida Scientist, 72(2), 134.

Marzolf, N., Smith, C., & Golladay, S. (2019). Limpkin (Aramus guarauna) establishment following recent increase in nonnative prey availability in Lake Seminole, Georgia. The Wilson Journal of Ornithology, 131(1), 179-184.

Mills, E. L., & Laviolette, L. (2011). The Birds of Brier Island, Nova Scotia. Nova Scotian Institute of Science.

Mouritsen, H. (2001). Navigation in birds and other animals. Image and Vision Computing, 19(11), 713-731.

Posch, H., Garr, A. L., & Reynolds, E. (2013). The presence of an exotic snail, Pomacea maculata, inhibits growth of juvenile Florida apple snails, Pomacea paludosa. Journal of Molluscan Studies, 79(4), 383-385.

Rawlings, T. A., Hayes, K. A., Cowie, R. H., & Collins, T. M. (2007). The identity, distribution, and impacts of non-native apple snails in the continental United States. BMC Evolutionary Biology, 7(1), 97.

Ricciardi, A. (2015). Ecology of invasive alien invertebrates. In Thorp and Covich's Freshwater Invertebrates (pp. 83-91). Academic Press.

Smith, C., Golladay, S., Waters, M., & Clayton, B. OF LIMPKINS AND APPLE SNAILS: INVASIVE SPECIES, NOVEL ECOSYSTEMS, AND AN UNCERTAIN FUTURE.

Veit, R. R. (2000). Vagrants as the expanding fringe of a growing population. The Auk, 117(1), 242-246.

Wilcox, R. C., & Fletcher Jr, R. J. (2016). Experimental test of preferences for an invasive prey by an endangered predator: implications for conservation. PloS one, 11(11), e0165427.

Fires, Fields, Turtles, and Trees

“Do you have muck boots with you?” Todd asked.  I kicked myself.  When packing for my Magee Marsh trip, I had neglected to bring either my boots or waders.  Would they be necessary to look for snakes, I inquired?  “Depends on whether you want to see spotties or not,” he said with a winky emoji.  My eyes widened and my pace quickened.  I hadn’t even considered looking for spotted turtles.  Finding my first Blanding’s turtles (and a mating pair at that) had seemed like a dream come true.  Now I was confronted with an opportunity so good I couldn’t pass it up.  Luckily, Todd had a pair he could lend me.  I raced back to my car, leaving the birds behind (again).  

Todd was out front loading his van as I arrived.  His open trunk was filled with boots, aquatic measuring equipment, and books from recent trips afield.  A wetsuit hung drying on his back fence near a sign that designated his garden the winner of the “best native wildflower planting.”  As a lecturer at the University of Toledo, Todd is an educator at heart.  His hands-on, in-your-face enthusiasm is contagious.  

The complexities of the ecosystem are what really get Todd excited.  He has managed everything from wet prairies and watersheds to local fish species and endangered mussels.  Todd was an excellent guide through the unfamiliar (to me) landscape of northwestern Ohio, pointing out fascinating hydrological phenomena and natural history at every turn. 

“See that field?” He gestured to a small woodlot along the road no bigger than my suburban backyard.  Widely spaced trees allowed a dense understory of vegetation to grow.  “Over 30 state listed plant species can be found right there,” he said.  

Most wouldn’t think of Toledo as a land of extremes—or that some of the rarest ecosystems on earth sit just west of the city.  Stretching over 180 square miles across three Ohio counties (and one Michigan county) the Oak Openings is perhaps the most unique part of the state.  Here, vast sand barrens intersperse with mesic prairies and oak flatwoods.  As many as 145 state listed plant species have been recorded from the Openings, including our only native cactus (Opuntia humifus).  

Wild Lupine (Lupinus perennis), a rare Ohio plant found only in the Oak Openings.

These rare ecosystems are maintained by annual cycles of extreme wet and extreme dry.  The secret lies in the sand.  The Oak Openings look as if someone dropped a little piece of the Mojave Desert into Ohio.  These rolling dunes are actually ancient sandbars, first deposited by a late-glacial precursor to Lake Erie between 11,000 and 9,000 years ago.  The sand can be 50 feet thick in some places, obscuring another important geologic layer: the till.  This impermeable clay holds any water that soaks through the porous sand.  Oak forests grow in uplands where the sand is thick and dry, while emergent open-canopy wetlands form where the till sits just below the surface.

The need for boots was immediately apparent as Todd and I stepped off the road.  The trail quickly opened up into a wide expanse of whispering Bluegrass, submerged in ankle-deep water.  We sloshed along, peering intently into every grassy hummock, hoping to catch the inky glint of a yellow polka-dotted shell.  Spotted turtles don’t typically bask on exposed logs like the more common painted turtle.  Instead, they bask nestled among vegetation, slipping into the shallow water at the first sign of trouble.  When the wetlands dry up by late summer, a complex network of underwater turtle highways are revealed.  Turtles not traversing their typical routes disappear into the muck without a trace, making them near impossible to find—unless you’re lucky enough to step on one.  “If you feel a rock beneath your foot,” Todd said, “it’s not a rock."

A female spotted turtle.  Note the pinkish-orange chin.

Once a common species throughout the state, spotted turtles (Clemmys guttata) have declined across the east coast and the Great Lakes region.  Ohio has lost close to 90 percent of its original wetlands, including most of the suitable spotted turtle habitat.  These turtles rely on wetlands to overwinter, moving into upland woods by late spring and summer.  The prime time to look for spotties is April and May while they are still basking near their aquatic hibernacula.  Once the temperatures start to heat up, these turtles become harder and harder to find as they spread out into the surrounding landscapes.

Todd called to me from several yards away.  I ran as best I could through the ankle-deep water, heart pounding at the thought of my first spotty.  Todd had bumped a small female with his boot, exposing the turtle’s hidden basking spot within the grass.  Held firmly but gently in his hands, the little turtle didn’t seem the least bit concerned.  She looked around bright-eyed and curious, legs waving as if walking in slow motion.  I was immediately struck by just how tiny this turtle was; she could fit comfortably in the palm of my hand.  Adult spotted turtles max out at around four inches in carapace length, making them one of our smallest native species.  

I was beyond delighted.  We took copious photos before releasing her back into the shallow water.  An hour later, I stumbled upon another, larger female basking out in the open.  We could tell these turtles were female for two reasons: one, the classic flat belly (males have a concave plastron) and two, her chin was a soft pinkish-orange.  Male spotted turtles have a much darker black or brown chin. 

As we half hiked, half sloshed our way back towards the vehicle, my foot brushed something hard.  Looking through the vegetated water, I was just able to make out a strip of bone nestled in the sediment.  My mind jumped to the sun-bleached shells of long-dead box turtles and snapping turtles that I’ve been lucky enough to stumble upon in the past.  I flipped the object over and was surprised to find a black plastron.  I knelt and plucked the small shell from the water.  Surprise number two: clenched between my thumb and index finger, a very much alive spotted turtle squirmed for freedom.  The large, keratin scutes that normally cover the animal’s back had completely fallen off, revealing the smooth bone beneath. 

A male spotted turtle missing the scutes along its back

It is unclear just what would could cause this kind of bizarre and dramatic disfigurement in a spotted turtle's shell.  It is possible this turtle survived being caught in a controlled burn that scorched just the outer layers of keratin and left the rest of the animal unharmed.  Alternatively, it could be suffering from some other physical trauma, exposure to toxins, malnutrition, or a bacterial or fungal infection. The fungus, Fusarium semitectum, is known to cause skin lesions and scute necrosis in desert tortoises.  Regardless of its ultimate cause, this deformity is symptomatic of many larger issues impacting the habitat these turtles call home. 

"A few years ago, this whole wetland would have been overrun with buckthorn," Todd explained.  Despite its natural appearance, the Oak Openings is anything but pristine. Human impacts are evident everywhere you look.  Settlers cut down the old growth oak stands and drained and channelized the groundwater in an attempt to farm the sandy soil.  Agriculture proved unprofitable, but the damage was done. As the surrounding areas developed, suppression of fires and a lower water table transitioned many natural openings into closed canopy forests. Even where the ground held enough water to exclude trees, introduced plants like buckthorn and cattails turned the once diverse fields of grasses, sedges, and rushes into mono-cultures. 

Intensive management is now necessary to maintain the Oak Openings’ unique ecosystems.  A strict regimen of selective cutting, herbicide use, and prescribed burns are integral to the plant and animal communities that depend on open habitat.  Without these scheduled burns, many native species, from butterflies to birds, would disappear. Spotted turtles would quickly become a distant memory.

Three spotted turtles by mid-afternoon was better than I could have hoped for, but I couldn't help but notice that another wet meadow species was conspicuously absent.  “There used to be massasaugas here?” I asked, knowing that the pygmy rattlesnake had been extirpated from all the lake counties thanks to human persecution.  “Yup,” Todd replied forlornly, “they were last recorded here in 1981."

Spotted turtles don’t suffer from the same violent disdain as snakes, but they face their own gauntlet of human mistreatment.  Plenty are killed on roads each year by oblivious drivers. Roadways and development have heavily fragmented the Oak Openings, splitting off habitats the turtles depend on.  Spotteds not killed crossing are commonly scooped up by star-struck drivers and taken home to waste away in captivity.  The pet trade is one of the biggest threats to the persistence of spotted turtle populations.  Black-market poaching focuses on adults (often gravid females) and can quickly collapse healthy turtle populations. 

Upwards of 500 breeding adult turtles is considered a viable population.  Many Ohio locality records are known from just one individual turtle, and groups of as many as 50 are still not considered sustainable long-term.  Being such a long-lived vertebrate, it can take decades before local extinctions are realized.  The Oak Openings is home to some of the larger remaining populations of spotted turtles in Ohio, but this rare wetland-loving woodland-dweller can still be found in isolated prairie remnants, bogs, and fens from northern to southwestern Ohio.  Their numbers are often so low that detecting them can be tricky, but given space, respect, and a little human help, they will hopefully persist long into the future.

Thanks for reading.
RBW  

Wind-swept Rattlesnakes

It was overcast.  Thinly veiled streaks of formless, gray-blue clouds stretched to the horizon.  The rapidly warming day was quickly approaching the perfect basking conditions that I’d been waiting for all morning.  I was feeling optimistic and energized.  The spring semester had just finished and I’d soon be heading to New Hampshire for a position at the Hubbard Brook Experimental Forest in early June.  That meant I had all of May at my leisure to pursue wildlife.  I wasn't about to waste a single minute that could be spent birding or herping.  

As I approached my destination, twenty five mph winds began to pick up.  The bare branches of trees and newly-emerged roadside greenery swayed and creaked as I gripped my steering wheel to steady myself.  Wind is generally not a friend to wildlife watchers.  It keeps the birds away and the herps under cover.  Old trees, aptly named “widow makers,” are of real concern.  Luckily, I was headed to one of Ohio’s last remaining Prairie remnants in Northwestern Ohio where the sparse trees pose little danger.  What I was there to look for, however, is another story entirely.   

I parked along a gravel ditch just as a small tree shuddered and gave way across the street.  The wind whipped across the open landscape, rustling through the grass as though hundreds of snakes were sliding all around me.  I suddenly began to understand the overwhelming sense of dread that ophidiophobes must experience when encountering a snake.  I strapped a pair of protective gaiters around each of my ankles.  There could be a concealed rattlesnake below any tuft of grass, and I wouldn't be able to see it or hear it over the gales.  

I’ve looked for Ohio’s two endangered rattlesnake species many times, but the smaller of the two has always eluded me.  Eastern Massasauga Rattlesnakes (Sistrurus catenatus) inhabit the wet meadows, bogs, and mesic prairies from New York to Ontario and as far west as Iowa and Missouri.  In Ohio, they were once considered commonplace across most of the glaciated half of the state.  Direct persecution, habitat loss, collection, and road mortality have reduced their 28 county range down to just nine remaining counties.  The eastern massasauga faces similar declines across eastern North America.  These snakes were recognized as nationally imperiled in the 70s and are thought to be extirpated from 40% of their original localities.  

Eastern Massasauga Rattlesnakes inhabit lowlands during the spring and fall, relying on crayfish burrows for cover and hibernation sites.  Water just below the surface that never freezes is a must.  If the frost layer penetrates the ground, the snakes will not survive.  Loss of suitable overwintering habitat or modifications to the water table quickly decimates massasauga populations.  Ohio alone has lost 90% of its original wetland habitat.  These snakes persist in landscapes that pose particular difficulty to agriculture, and were subsequently left relatively unchanged.

Uplands are just as important to massasauga ecology.  During the summer months, snakes move into upland forests to forage.  These landscapes are often unprotected or heavily developed, resulting in population declines even when the adjacent wetlands are protected.

With each step, water bubbled up through every crack and burrow in the mud.  I hadn’t walked one hundred meters from my car when I froze. Sitting coiled in a tight bun atop an elevated pile of dry prairie grass was a massasauga rattlesnake.  My heart raced as I took a few steps back and freed my camera from my pack.  I crept around the motionless rattlesnake, it’s dark body burning into my retinas.  Upon closer inspection, it became clear that this snake was not black, but tan with dark brown blotches; its triangular head and unblinking eyes were clearly visible through the tall grass.  Stretched out, the sauga would probably measure over two feet (these pigmy rattlesnakes max out at just under three feet).

I kept a respectful distance, well outside of the snake’s strike range, but I still didn’t want to startle the sleeping viper.  As I moved for a clearer shot of the head, the snake suddenly became aware of me.  Striking or even rattling unless thoroughly provoked is almost unheard of.  Massasaugas typically remain motionless, allowing the threat to pass by unawares.  Perplexing, the massasauga twitched in agitation with an almost copperhead-style movement as it coiled its neck and raised its buzzing tail.  I was shocked.  I’ve encountered timber rattlesnakes at closer range and never had one so much as tongue flick.  I stepped away, allowing the snake plenty of room to escape.  Butt still buzzing, the sauga slipped below the tangles of grass and out of sight.  I suddenly felt very glad I was wearing gaiters.  

I am confident that this uncharacteristic encounter was down to individual personality.  Carl Brune often tells the story of two eastern hog-nosed snakes he hatched from eggs.  One sibling would play dead whenever approached, while the other would only flare its hood and hiss.  Snakes are as much individuals as you or I.  

During the course of my search, I encountered three more massasaugas.  Two never budged as I watched and photographed them.  The third was found out on the crawl, and while it did coil up upon my approach, it never rattled or gave the faintest impression that it felt threatened.  After a few minutes, it slowly turned away and drifted off into the tall grass.  

After that first encounter, I was primed to be a bit jumpy.  I was scared half to death when a snake came lunging out of the tall grass in full strike, mouth agape.  After the initial shock wore off, I looked down to see a large, but utterly harmless, eastern gartersnake.  “What are you doing??” I said aloud, holding back laughter.  I plucked the grumpy garter from the grass and placed him off the trail.  Snakes, venomous and nonvenomous alike, have no interest in biting if they don’t have to.  All they want is to be out of harm's way.  Sadly, senseless killing by ignorant or fearful snake-haters continues.  It is not unheard of to discover a dead sauga with its rattle cut off—as a trophy.

Even where massasauga populations appear stable, a new threat has emerged on the scene.  In 2006, a fungal pathogen called Ophidiomyces ophiodiicola was discovered in Timber rattlesnakes.  This fungus targets wild and captive snakes, primarily rattlers and colubrids, in eastern North America and Europe.  It penetrates the epidermis though any small wound and causes lesions and blisters to form across the snake's head and body.  The origin and dispersal mechanism of this fungus are unknown, but it can survive in the environment without a host for some time.  Whether this fungus was introduced or a native turned virulent, it appears to work in tandem with other environment stressors like habitat modification and climate change.  Some snakes may be able to shed repeatedly to keep the fungus at bay, but many succumb as the infection attacks the deeper layers of skin, muscle, and bone.  Massasaugas are particularly vulnerable to this Snake Fungal Disease, and their already dwindling populations are being pushed closer toward extirpation by its spread.

I've visited many historical localities where the tufts of wiregrass and crayfish burrows no longer harbor wild massasaugas due to poaching and habitat modification.  Without their swamp rattlers, these wet meadows, fens, bogs, and prairies feel eerily empty.  It would be an irreparable shame to see the littlest of Ohio's vipers disappear from its final strongholds.

Thanks for reading!
Keep living the field life.
Ryan

An "Aberrant Eastern Gartersnake"

Plains gartersnakes (Thamnophis radix) are a common species from south central Canada through the Great Plains to Texas and Oklahoma.  Across this expansive range, their populations can reach densities of 300 individuals per acre.  They are not a rare snake by any stretch of the imagination.  In Ohio, however, the entire range of this species is restricted to just one county within one prairie remnant (and not even the entirety of that).  Ohio plains garters are snakes out of time.

5,000 years ago, the climate in Ohio was very different than it is today.  The Xerothermic period, as it is called, was significantly dryer and hotter by as much as five degrees Celsius with 25% less rainfall.  For several thousand years, Ohio’s climate closely resembled modern day Kansas.  This warm, dry period was marked by an expansion of western biota into the state.  Flora and fauna that we associate with the great plains, found suitable habitat in this “prairie peninsula.”  When the climate shifted again (to the cooler, wetter present), the prairies receded, leaving behind a few isolated prairie pockets where clay soils inundate the landscape for much of the year (such as on ancient riverbeds), preventing the expansion of forests.  Today, agriculture has reduced the 12,000 ha of contiguous wet prairie across northwestern Ohio to a few thousands disjunct hectares.  

The entire Ohio Plains Garter population is so localized that these snakes were not verified in Ohio until 1945.  Even the great herpetologist, Roger Conant, who collected the first specimen in 1931, mistook the washed-out DOR (dead on road) snake for an “aberrant eastern gartersnake.”  This is the ultimate case study in local abundance.  While these snakes would have originally inhabited a larger expanse of the available prairies in Ohio, habitat loss and land-use changes have reduced their already limited populations by as much as 94% in some areas.  Where they still occur, there can be hundreds per acre.  However, the sympatric eastern gartersnake (Thamnophis sirtalis sirtalis) outnumbers the plains by about ten to one.  If I had any hopes of finding a plains, each and every striped snake I discovered would have to be thoroughly examined.

A terrestrial crayfish burrow 

In preparation for a long week of finals, my girlfriend, Julia Joos, and I decided to take a weekend herping trip to unwind.  We arrived in northwestern Ohio in the evening, anticipating an early morning search the following day.  The weather, however, had other ideas.  That night brought storm clouds and frigid temperatures that stuck around until late afternoon.  The clouds finally burned off just a few hours before sunset.  We hoped the timid sunshine and mild temperatures would be enough to entice the snakes to bask. 

The flat expanse of fields and croplands intermitently bisected by roads might not look like much to the passing observer, but I could tell right away that this habitat was great.  Hollow mud chimneys—the entrances to the burrows of the terrestrial crayfish species Falicambarus fodiens—were everywhere.  These burrows are not only a sign of high water quality and good soil chemistry, they also provide the snakes with refugia during inactive times of the day and year.  Modify the water table or introduce pollutants that wipe out the crayfish, and the snakes will invariably disappear along with them.  

In early spring, the vegetation is still brown and brittle, weighted down from months of snowpack.  With their lateral stripes, gartersnakes camouflage perfectly among the criss-crossing network of dried reeds.  I hiked quickly, scanning the ground and listening for rustling movement.  Julia was more careful.  She found the first snake of the day in a spot I had tromped right over.  It was an eastern gartersnake, still muddy from the crayfish burrow it had recently emerged from.  During the next hour, we found half a dozen more garters, but none were quite what we were looking for.  I finally resolved to photograph one of the more colorful individuals coiled up among the mud and grass.  As I set up my camera, Julia called out from just over my shoulder.

“Oh, here’s another one!” she said.  I turned around to see a large gartersnake coiled among the grass.  “Nope!” I laughed, “that’s our radix!”  Had I not been looking for the subtle defining characteristics of the plains garter, I easily could have passed this snake by.  Even through the snake’s mud-dusted scales, I could tell its stripes were unusually black.  The dead giveaway that this was our plains garter, however, was the yellow-orange stripe running the length of the garter’s back.  Out of the hundreds of variations of the eastern gartersnake that I have seen over the years, none have had a stripe quite that color.

The garter cooperated nicely, coiling in front of us and tongue flicking.  After a few shots the snake decided it had had enough, and zipped away through the grass.  The purpose of those stripes becomes clear when a garter flees through a vegetated landscape.  longitudinal stripes make it significantly harder to judge the snake's speed, length, and direction.  The plains garter seemed to almost meld with the landscape it so depends on. 

A juvenile plains gartersnake (Thamnophis radix)

On a return visit to the area a few weeks later, I was lucky enough to find a juvenile plains gartersnake, a good sign that these endangered snakes are breeding.  Despite the perilous predicament these snakes find themselves in, very little management is directed towards their conservation.  Reintroduction efforts through captive breeding have been underway for years, but these snakes still face a host of threats in their final stronghold.  The landscape they call home is primarily managed for waterfowl hunting.  Scheduled mowing of their field habitat has been shifted to coincide with snake inactivity, but individuals are still occasionally killed.

Like that first specimen found by Conant in the 30s, road mortality is one of the easiest ways to discover this species.  I found a large adult T. radix, carelessly crushed by a speeding vehicle as the harmless snake attempted to cross between habitat patches.  Even though plains gartersnakes are common across the great plains, the disjunct populations in Ohio, Missouri, and Illinois all represent unique genetic lineages.  They are important contributions to the biodiversity of our state and to the persistence of these remaining prairie patches.