Photo By Michael Strasser | Fred Ossman, Fort Drum wildlife biologist, has spent the past two springs...... read more read more
FORT DRUM, N.Y. (June 14, 2018) -- Fred Ossman, a wildlife biologist with the Fort Drum Natural Resources Branch, has spent much of his time this spring “chasing wood turtles” – trekking through woodlands and paddling up and down streams in the post’s training areas.
The wood turtle is a species of special concern in New York – meaning, they are not currently listed for federal protection as an endangered species but are likely to be considered threatened. So, for the past 14 months – weekdays and weekends, sometimes sunup to sundown – Ossman has been learning everything he can about the wood turtles that live on the post’s training areas.
Ossman began working for the Natural Resources Branch in 2009, and he said that until he began this project, the data they had on wood turtles were mostly anecdotal reports and photographs collected from survey crews in the late 1990s and early 2000s.
He said that under the Convention on International Trade in Endangered Species (CITES), the wood turtle is listed under Appendix II, which means they are not in danger of becoming extinct, but without proper management, it is likely they may be listed as such in the future.
“The wood turtle will be up for consideration in 2023 as a threatened species,” he said. “The information I gain here will allow us to develop a conservation and management action plan so we can potentially increase the population numbers while protecting our wood turtle population that we do have. With this proactive management, Fort Drum can be squared away, and this will keep us ahead of the power curve in the event this species is given federal protection.”
Jason Wagner, Fort Drum Natural Resources Branch chief, said that being proactive with data acquisition will mean less challenges later if any requirements are imposed by the U.S. Fish and Wildlife Service.
“If we didn’t do this now, and waited for the Service to tell us what to do, we would have significant challenges while we figured out how any requirements might impact military training,” he said. “If the turtles spent all of their time in the streams, there would be no impact, because Soldiers spend little, if any time, within the stream during training. But since wood turtles are found in the woods, that’s where there would be impact to training, between turtles nesting and Soldiers and Humvees driving around. So, Fred has the lucky job of spending his time running up and down the streams chasing turtles.”
The work entails more sleuthing than chasing. Ossman carefully scours forests, stream banks and areas of land where wood turtles are most likely to hibernate, mate and nest. When he finds a wood turtle, he secures a small radio transmitter on its shell with a waterproof epoxy. The transmitters will function for at least 660 days, and to track their locations, and discern movement patterns and habitat preferences. Ossman uses a portable antenna along with the radio receiver made by Advanced Telemetry System.
“It’s a very simple technology that has been used for many years for everything from whales to turtles, birds and bats,” he said.
The transmitter emits “beeps” to indicate proximity to the wood turtle’s location, which is also indicated by the number of bars displayed on the screen – much like a phone tracks the strength of cellular service. Ossman will swing the antenna around until he finds the right direction to move, even if that sometimes means walking through thick brush – which can be a struggle getting the antenna through – to get there.
So far, the data he is accumulating using simple, predictive models is showing a fairly robust wood turtle community at Fort Drum – at least in the areas they have been able to survey, Ossman said.
“What the baseline data will tell us are things like the average home ranges of males and females, how far from the banks of the creeks they travel, their movement patterns and how their conservation efforts could conflict with military training,” he said. “So far, I don’t think it conflicts. Even though they’re a scattered population, data derived so far appears favorable to both the turtle and the mission. The numbers don’t look too bad right now.”
Sometimes what Ossman learns can be surprising even to him. He said that over the Memorial Day weekend, one female turtle was recorded to have moved upstream for about two and a half miles.
“For a turtle that’s pretty fast,” he said. “It’s surprising that she moved that far – to nest, I’m assuming. Wood turtles can move around with some speed; they’ve got very strong legs for their size, and they’re excellent climbers.”
Currently, he is tracking eight turtles – five female and three male – but he had hoped for a much larger number. Until recently, Ossman was tracking a ninth wood turtle (a female) until it was found dead on a dirt road near a bridge. He recovered the smashed transmitter, and while a road mortality is a regrettable incident, Ossman said that it was fortunate the turtle was not carrying any eggs.
“This will be my eighth field season at Fort Drum, and I’ve never seen a roadkill wood turtle and, of course, it had to be one that I was tracking,” Ossman said. “It was my favorite one too.”
Ossman tracks the turtles at least once every week to get a visual on them, and some he will locate on a daily basis to see if they made any big moves.
“Sometimes it’s just a spot-check to see if they are still in the same area, or else I’m on foot attempting to look for them,” he said. “There are days where we spent the better part of a day looking for a specific turtle and never finding it, probably because it was in the water and we couldn’t get a good visual on it.”
Ossman said that when wood turtles hibernate, they tend not to move too far from that site. When they do, it is probably the result of flooding or ice floes that dislodge them, predators or other animals moving into the area. He doesn’t suspect that the noise from military training disturbs the wood turtles. In fact, the one female that was killed on the road had made its hibernacula (place of hibernation) in a stream directly below a fixed artillery site.
“She didn’t move at all,” he said. “She tucked herself up under an old beaver dam and slept the winter away. They don’t hear like us, but they do pick up the low intensity soundwaves. If there’s a lot of activity in an area, we might detect them another time up to a kilometer or more away where they’ll find a new area, nice and quiet, and hang out there.”
When a wood turtle isn’t hibernating, it is likely to be found foraging in the forested uplands and field edges, basking on the crest of a stream, or in the water. So, when Ossman isn’t trekking on land, he takes a poke boat – a half canoe, half kayak hybrid – onto the streams.
“Coasting down the creek banks and grabbing them while they’re basking out in the sun is about the only way to find them this time of year once the leaves are fully grown out,” he said. “Although, in mid-May through June, the fields where the females are nesting are still pretty short. They seem to like the short grass fields early in the season when the vegetation is shorter, but during the warmer months they tend to retreat to the upland forests or taller vegetated fields containing plants like the goldenrod.”
Wood turtles do not reach sexual maturity until 14 to 18 years of age, producing only four to 10 eggs per year. Females may not mate every year. Ossman said that a species of this nature tends to have a lop-sided population demographic – more adults and few juveniles.
“I have gotten three or four I have seen documented, so it’s nice to know that at least a few of them are making it toward adulthood,” he said. “It’s been calculated by several authors that 90 percent, at a minimum, to 99 percent of all eggs are depredated by predators.”
The most common predators are raccoons, skunks, fox, crows and ravens.
“It’s easy pickings, and the nests can be fairly easy to find by scavengers,” Ossman said. “Turtle hatchings are called nature’s potato chips. The biggest predators out here are probably snapping turtles and otters. Snapping turtles will actually take an adult’s legs out with their claws. Otters may do that too, although otters tend to seek more plentiful prey species such as fish, mollusks and crayfish.”
Ossman said that he and his interns discovered a site with 11 nests depredated by predators last year.
“That was disheartening to see all those nests destroyed, but that was an unknown area that I didn’t know wood turtles had been using, moreover, that there could be up to 11 more female wood turtles in the general area,” he said.
This, and other nesting sites found, beginning with the 2017 field season, contributed a great deal of valuable information toward the development of a conservation plan, he added.
Another component of his project is to find the nests of the female turtles and incubate their eggs back at his office. This increases their survivability rate significantly when he returns them to the nesting area.
He also supported an Eagle Scout project a few years ago where Scouts placed anti-predator nesting structures in the training areas that should have promoted greater reproduction rates for the wood turtles. Ossman said he observed a female turtle investigate the structure several times, but she hadn’t felt comfortable enough to nest inside of it.
“That’s disappointing,” he said. “We have turtles, all the time, nesting just outside of them, but never inside. I’m not sure if it is because of the material that we used or because the structures are still relatively new and wood turtles have not yet become accustomed to them.”
Instead, and what Ossman will be working toward, is developing at least three conservation areas with anti-predator devices.
“It’s creating, essentially, protected nesting areas that are well off the road and closer to the environment that they like,” he said. “Portions that are the most attractive for nesting will have electrified wire set up and charged to keep predators out during the nesting season. I hope to have them up and running by this time next year.”
Ossman said that the idea is to discourage depredation by improving their chances of survival into the reproductive years, which should increase the population.
“Unfortunately, again, they don’t become reproductively mature until they are of 14 to 18 years, and I’ll be long retired,” he said. “I’ll have to read about it to see if this worked, which in itself depicts how vulnerable these populations are to depredation and other forms of mortality, as well as habitat loss.”
The wood turtle’s primary defense mechanism may be its ability to conceal itself in its environment.
“They put a lot of stock into their camouflage,” Ossman said. “Their shell looks just like a piece of bark, and once they pull themselves inside they will just hunker down. It’s amazing how they can just disappear under the leaf litter or a few sticks on the ground. You could be just about ready to step on one, and it will not move.”
That is how Ossman found one, accidently hitting it with the side of his boot. Even when the antenna picks up a turtle’s location, getting eyes on it can become an exercise in futility.
“I had the antenna inches away from a wood turtle before and still couldn’t see it until we were on our hands and knees,” Ossman said. “We started feeling around for it and found it just underneath the thatch. I wouldn’t have seen it until she turned her head and I saw that big, orange chin emerge from the leaves and sticks.”
“One of our females always go deep in the thick alder stands by the creek, and several times we stopped trying to find her just to preserve our equipment,” he added. “My interns and I were getting beat up trying to get through it. It’s not uncommon to come out of the field with a whole lot of scrapes and cuts.”
Ossman said that he prefers to keep his distance from the wood turtle when possible.
“I’ve found if you push them too much, they probably will take off,” he said. “Otherwise, they don’t usually move too far away until it is time to hibernate. If they move more than five meters, especially away from the stream, I will mark that point because what I want to calculate the most is how far up into the training areas do they go. We could use that for analysis to see if there’s any conflict with military training.”
Ultimately, Ossman said he would like to advance this beyond a pilot study – regardless if the wood turtle is listed as an endangered (threatened) species – and have college or university student researchers continue the project.
“I would eventually like to turn this over and get some real scientific results done, beyond the modeling and statistics I can do,” Ossman said. “Because of my other responsibilities, I can’t do this all the time. Probably after June, I will only be able to get out here once or twice every week or 10 days just to check on locations, taking a GPS point when any turtle moves more than 10 meters.”
Of the eight turtles being tracked, Ossman said that only one is a “known,” meaning it has been documented during previous field seasons.
“The color pattern on their plastron (lower shell) is a thumbprint, essentially,” he said. “Going back through our files, about ’97-ish, I was able to get together a population of 14 individual wood turtles that have been seen and documented before the 2017 field season. You can use that splotch pattern as an individual identifier.”
Ossman said that for a species formerly believed to be uncommon and widespread, he has been pleasantly surprised by all of the sightings.
“Jeff (Bolsinger, wildlife biologist) saw another one by the bridge over here just Monday morning. If it wasn’t my day off, I would have been over there ASAP. We’ve put the word out to the group (at Natural Resources) that if you see one, give me a call.”
That’s the message the Natural Resources staff is hoping to convey to any recreational hunters, anglers and Fort Drum employees working in the training area. To report a wood turtle sighting, call (315) 774-2746.
Ossman also hopes that Soldiers and recreationists driving through training areas exercise more caution on the roads, especially since wood turtles tend to travel near bridges and culverts, particularly during nesting season.
“Like I said, I’ve only seen one roadside mortality in eight years, so that is good news,” he said. “But it’s never a good thing to see. It is especially disturbing to observe tire tracks deliberately swerving into a dead turtle.”
According to the Department of Environmental Conservation, thousands of turtles are killed in New York state each year when they are struck by vehicles while migrating to nesting areas. The DEC reminds the public that the state’s native turtles are on the move in May and June, seeking sandy areas or loose soil to lay their eggs.
Drivers should use caution and not swerve suddenly or leave their lane of travel when seeing a turtle on the road.
The DEC also notes that all native turtles are protected by law and cannot be collected without a permit.
For more information, visit https://www.dec.ny.gov/animals/277.html.
| Date Taken: | 06.14.2018 |
| Date Posted: | 06.14.2018 14:26 |
| Story ID: | 280952 |
| Location: | FORT DRUM, NEW YORK, US |
| Web Views: | 199 |
| Downloads: | 1 |
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