Black-legged Ticks
This marks the 20th anniversary of my column for the Pennsylvania Game News. The first appeared in January 1993 and concerned the Carolina wren. Thanks for reading!
—Marcia
Last January I walked along the Black Gum Trail. Since our son, Dave, constructed the trail halfway up Laurel Ridge, back in the 1990s, I had never been able to take the trail in winter. Usually, it was deep in ice and snow as was our north-facing hollow road. But on that mild day there was not a smidgeon of ice or snow on the trail or road.
I neither saw nor heard any creature despite the warm day. The long-promised sun was trying to shine through a matrix of puffy, white clouds drifting past patches of blue sky. At dawn it had been 34 degrees and breezy, and the thermometer had been slowly rising all morning.
Then, as I descended the trail, I glanced down at my pants and socks and pulled off seven adult black-legged ticks. I could hardly believe it. I had considered winter to be tick-free on our mountain. Usually, they spend their winters buried under leaf litter that should be covered with snow. But they are tough creatures, and as soon as it warms up they are out and about. At that time the adult females are not carrying Lyme disease because they had had their last blood feeding on white-tailed deer. Some even winter on the deer.
But, as Dr. Richard S. Ostfeld of the Cary Institute of Ecosystem Studies in Millbrook, New York says, don’t blame deer if you get Lyme disease. The immune system of deer kills the bacteria that cause the disease.
“We don’t know why,” Ostfeld says, “but the deer immune system clears the infection. When they get bit, they wipe out Lyme. Deer play a tremendous role in suppressing adult ticks from spreading the bacteria.” He also dislikes the name “deer tick” and prefers “black-legged tick.”
White-tailed deer in Plummer’s Hollow (photo by Dave Bonta)
After all, like any arachnid to which ticks are closely related, the nymphs and adult ticks have eight black legs. But the larvae only have six. The larvae hatch from the several hundred to a few thousand eggs each female adult tick lays in spring. She then dies. Both the larvae the first summer and the nymphs the second summer feed once on a mammal and prefer white-footed mice, although they will feed on other small mammals or birds if they can’t find a mouse.
And it is white-footed mice that are the real culprits. They can get the Lyme disease bacteria and pass it on to the ticks even though the bacteria don’t seem to sicken them. Because nymphs are so small, no larger than a poppy seed, they are liable to bite and never be detected during the three to four days they need to take their blood meal. At least 70% of Lyme disease cases are from those nymphs that do not look like the black and reddish-brown adult female ticks. Instead, they have dark heads and bodies that appear to be translucent. Adult male ticks, which don’t feed but will attach to a host when searching for a female to mate with in the fall, are either black or dark brown.
Entomologist Thomas Say named the black-legged tick — Ixodes scapularis — back in 1821. But the first known case of Lyme disease wasn’t identified until 1975 when several children in Lyme, Connecticut were diagnosed with juvenile rheumatoid arthritis. It turned out to be what later was named Lyme disease. In 1982 scientist Willy Burgdorfer isolated the bacterium causing the disease, and it was named in his honor Borrelia burgdorferi.
Scientists also thought that a new species of tick carried the disease and named it Ixodes dammini. It was only later in the 1990s that they realized the tick transmitting the disease had been around and named long ago. But they did recognize that the tick belonged to the family Ixodidae, the so-called hard ticks. They have a hardened plate called a scutum on their idiosoma region, which is a specialized part of a tick’s body that expands to hold its blood meal.
White-footed Deermouse (Peromyscus leucopus) by J. N. Stuart (Creative Commons BY-NC-ND license)
Like ticks everywhere, the nymphs and adults climb a shrub or blade of grass, hold out their forelimbs, and wait for a victim to brush past. They also lurk on fallen logs, tree trunks, or even on the ground, especially the nymphs which can’t climb as high as the adults. Since they arrived on our mountain, about six years ago, I no longer have the pleasure of sitting on my hot seat on the ground, my back against a tree, watching the life of the forest. They even reach me on our benches unless I pull my feet up on to them.
Ticks have a Haller’s organ on each foreleg with spiny indentation packed with sensors and nerves capable of picking up a breath of carbon dioxide, heat, sweat, or even vibrations from your footsteps. So no bird or mammal can escape their sudden lunge. As I’ve discovered, the small huckleberry shrubs on Laurel Ridge Trail and the grasses of First and Far fields, are ideal “questing” posts for ticks, as well as the underbrush in our forest off the trails where I rarely venture anymore.
Once a tick arrives on its host, it probes around for a soft, bloody site to attack, often in private crevices. Normally, you won’t feel a thing. As David George Haskell writes in The Forest Unseen, “I suspect they charm our nerve endings, taming the cobralike neurons with the hypnotic music of their feet.”
The tick presses its mouthparts into your flesh and saws an opening. Then they lower a barbed tube, called the hypostome, to draw out blood. Because it takes several days to get a full blood meal, it cements itself to your skin with a glue-like material called “attachment cement,” which is why a tick is so difficult to remove.
During the first 24 hours it is attached, it is harmless. But later, when it is full, it takes water from your blood into its gut and spits it back into you, which is when it can transmit Lyme disease or two other diseases — babesiosis and anaplasmosis. The parasite Theileria microti causes babesiosis and Anaplasma phagocytophiolum causes anaplasmosis. As many as 2 to 12% of Lyme disease patients will have anaplasmosis and 2 to 40% babesiosis. This complicates the diagnosis and treatment sometimes because the tick might transmit one or the other or both diseases and not Lyme to a patient. In rural New Jersey, for instance, the Center for Disease Control studied 100 black-legged ticks and discovered that 55 of them had at least one of the three pathogens.
Black-legged tick by Jerry Kirkhart (CC BY license)
Both babesiosis and anaplasmosis have flu-like symptoms similar to those of Lyme disease but without the telltale bull’s-eye rash. Some folks don’t recognize or even have symptoms of babesiosis, yet they can pass it on to others through donated blood. So far, Pennsylvania seems to be almost free of those two diseases, but they are more prevalent in New York and New Jersey. Unfortunately, it is probably only a matter of time until these diseases increase in the commonwealth.
Last year was supposed to be especially high in Lyme disease cases. That was because in 2010 there was a bumper crop of acorns, followed by 2011 when there were practically none. Dr. Ostfeld, forest ecologist Dr. Charles D. Canham, and colleagues at the Cary Institute first worked out the connection between the amount of acorns and the population size of white-footed mice. In abundant acorn years mice numbers soar but they crash when the acorn crop fails. According to Ostfeld, that leaves a large number of infected ticks looking for hosts. Without the mice, they are after us instead.
At least one hunter friend of ours contracted Lyme disease last June. Although he did get the rash, he never saw the tick. I suspect it was a nymph that bit him. He also listed four places where he could have picked up the tick — turkey-hunting at our place, at a friend’s country property, and on his own country property, or his backyard at the edge of Altoona.
If Ostfeld’s research is right, his backyard was the most likely habitat. In a paper for Conservation Biology Ostfeld and other colleagues entitled “Effect of Forest Fragmentation on Lyme Disease Risk,” they wrote, “Our results suggest that efforts to reduce the risk of Lyme disease should be directed toward decreasing fragmentation of the deciduous forests of the northeastern United States into small patches… The creation of forest fragments of 1-2 hectares should especially be avoided, given that these patches are particularly prone to high densities of white-footed mice, low diversity of vertebrate hosts, and thus higher densities of infected nymphal black-legged ticks.” Given both the size of our forest and the diversity of vertebrate species, we should have less Lyme disease here.
Berberis thunbergii – Japanese Barberry berries by Virens (CC BY-NC-ND license)
On the other hand, another study by Tom Worthley and other researchers at the University of Connecticut Forest in Storrs claims that eliminating the invasive Japanese barberry shrubs (Berberis thunbergii) will help control the spread of Lyme disease, anaplasmosis, and babesiosis because white-footed mice favor the barberry’s habitat.
“When we measure the presence of ticks carrying the Lyme spirochete we find 120 infected ticks where barberry is not contained, 40 ticks per acre where barberry is contained, and only 10 infected ticks where there is no barberry,” Worthley says.
Unfortunately, our neighbor’s old 100-acre property that we were able to purchase only after it was poorly logged, is filled with Japanese barberry and other invasives. It’s also moved into the edges of our fields and even into the edge of portions of our older forest. Eliminating all of these bushes will take many manpower hours. But our caretaker hopes to experiment with a few of his own ideas for removing them over the next several years.
In the meantime, I’ll continue to follow most of the suggestions for avoiding tick bites, including super vigilance of my clothes and body, even in winter, when I take my daily walks.
The Joy of Trail Cams
All photos and videos in this column are from trail cams on the mountain placed and monitored by the Scotts. (If you’re reading this via email or in a feed reader, you may have to click through to see the videos.)
Almost as soon as they settled into their new home, back in 2009, our caretaker couple — Troy and Paula Scott — installed three strobe cameras. As avid hunters, they were interested initially in monitoring the movements of deer over our square mile of mountain property.
But soon they were capturing other creatures on their cameras, especially at night. Paula quickly became the chief monitor of their cameras, and when the company that produced their strobe cameras — Wild Game Innovation — came out with video cameras, they purchased three of them.
Paula admits that monitoring the cameras throughout the year is addictive to her. She used to dislike winter, once hunting season ended, but now it’s her favorite time of year. That’s because she uses bait to attract a wide range of wild creatures. She hangs a discarded deer carcass by a wire from a tree limb, so it swings a foot or two off the ground directly in front of a camera.
Of course, when bears are abroad, she does not use bait, although she did get a bear on the surprising date of February 27. And that’s what she likes most about the cameras. She learns more about animal behavior especially with the video cameras. In less than two years, she has gotten excellent footage of 15 species of birds and mammals.
Her favorite sighting so far has been of two different fishers that kept returning to the bait. One especially she describes as a “camera ham.” It swung back and forth with the carcass and often faced the camera. Then it turned on its back and rolled with the carcass. All the while it seemed puzzled by this strange source of food.
Both Paula and I have had excellent sightings of fishers in our woods. We’ve also seen tracks in the snow. But the video footage of fishers gave us a whole new perspective on fisher behavior.
Watching two raccoons and an opossum feeding peacefully around the carcass was another surprising behavior observation for Paula.
“I figured they would be competitive and they weren’t,” she says.
She was also surprised that an American crow fed beside five turkey vultures.
And both she and Troy were amused and chagrined when an old hen decoy they had used to unsuccessfully attract gobblers years ago proved irresistible to six jakes at a time. She even has a video of a gobbler displaying in front of the decoy.
Besides the fishers, her other favorite sightings are several photos of a bobcat at the bait at night and a lovely video of a red-tailed hawk near the bait during a snowy day. I’m particularly fond of photos she has of red and gray foxes, despite the presence of coyotes in our area, because coyotes are supposed to prey on red foxes.
Recently they used a camera to find out what was chewing on their new deck at night. As they suspected, it was a porcupine. Instead of killing it, they put a cayenne pepper mixture on the deck and so far it’s kept the porcupine away.
Their original plan, to document deer, also has worked out well. They even have videos of a buck making a scrape and putting his scent on an overhanging limb. Paula cautions, though, that putting the cameras out during deer breeding season gives a false sense of the number of bucks in a hunting area because bucks come in from adjoining properties in search of doe.
When targeting deer, they put the cameras along obvious deer trails, leave them for a month, and then switch them. For other animals, it depends on the time of year and how successful the location is in capturing wildlife footage.
Learning how to obtain good images during the day means positioning them so that the sun doesn’t shine on them, otherwise, you end up with a lot of white footage, she says. You also have to hope that a bear won’t take issue with them. Paula’s brother-in-law Jeff had one ripped off and stomped into pieces, but so far they’ve been lucky. Only two cameras have been pulled down but not damaged.
Paula says in summary that, “these cameras, if you utilize them all year, pay for themselves. If you have a deer interest, as we did, and invest in cameras, you see it’s just not deer out there. It’s a lot of things.”
a bobcat at the bait pile
Discovering what’s out there has tempted folks throughout the world to invest in trail cameras. One writer friend, Ken Lamberton, recently posted on Facebook a beautiful photo of a cougar on a fallen tree in the Mule Mountains of southern Arizona where he and his wife Karen live.
Speaking of cougars, Valentine, Nebraska businessman Kirk Sharp has 16 trail cameras posted around his ranch, which is a half-mile north of Rocky Ford on the Niobrara River in the wild north-central section of Nebraska. One of his cameras, mounted on a wooden fencepost, captured a cougar closely chasing a deer at 11:00 p.m. It was the first authenticated footage of a cougar chasing prey in the state, although since there was a deep canyon directly in front of them, no one knows the outcome.
James Hill III of Waterford Township, Erie County, Pennsylvania wondered what was taking the suet at his feeders. Hill, the founder of the Purple Martin Society, has a 150-acre wildlife sanctuary. Although he figured a bear was probably doing the damage, he put out a camera with a motion detector. To his surprise it was a sow with two cubs sharing the suet with them.
“I was astonished,” Hill says. “I never figured there’d be a family. I’m happy to have them.”
While individuals are enjoying their cameras, and finding out more about wildlife on their properties, so too are wildlife biologists. For instance, two researchers from Texas Tech University — Blake Gresham and Phil Borsdorf — have been studying the endangered lesser prairie chicken at The Nature Conservancy’s Yoakum Dunes Preserve near Lubbock, Texas. By erecting remote video cameras on 15 water tanks at the Preserve, they photographed 800 visits to the tanks by lesser prairie chickens, disproving the belief that the birds don’t need open water because they get enough moisture, except during drought, from succulent plants, insects, and dew. Gresham and Borsdorf found that hens especially needed extra water during nesting time because it takes a cup and a half of water to produce a clutch of ten eggs.
gray fox
Conservation organizations are also starting to utilize trail cameras. A recent article in the Philosophical Transactions of the Royal Society Biological Sciences entitled “Community Structure and Diversity of Tropical Forest Mammals: Data from a Global Camera Trap Network” recounts the results from the world’s first global camera trap mammal study. It involved nearly 52,000 candid shots of 105 mammal species from seven tropical sites around the globe.
The camera traps, low on the ground, made no noise and emitted no light so poachers couldn’t spot them at night. But in Africa, elephants, like our black bears, don’t like strange objects in their territory and tried to crush them.
Jorge Ahumada, the lead author and an ecologist with the Tropical Ecology Assessment and Monitoring Network (TEAM) says that “The study shows for us that for the conservation of these mammal species, size matters; …the size of the protected area and the degree of human activity around it have an effect on the …diversity of these animal communities.”
The Central Suriname Nature Reserve in South America had the most diversity — 28 species — while Nam Kading in Lao Public Democratic Republic in southeast Asia had the least — 13 species. The other sites included Uganda and Tanzania in Africa, Indonesia in Southeast Asia, Brazil in South America and Costa Rica in Central America.
The study ran from 2008-10 under the auspices of Conservation International, the Missouri Botanical Garden, the Smithsonian Institution, and the Wildlife Conservation Society. Because of its success, they have expanded it into 17 wilderness areas in Panama, Brazil, Peru, Madagascar, Congo, Cameroon, Malaysia and India. Ahuda says that these cameras “are reliable observers of the state of our world,” and the study concludes that “camera traps are a useful, efficient, cost-effective, easily replicable tool to study and monitor terrestrial mammals.”
They are also useful for studying large raptors. Dr. Todd Katzner at West Virginia University, along with Kieran O’Malley and Rob Tallman of the West Virginia Department of Natural Resources, is using them for estimating the size of the wintering golden eagle population in the Appalachians including Pennsylvania. The bait is road-killed deer dumped into a small clearing surrounded by tall trees where golden eagles can perch. The bait should be opened along the legs and abdomen to draw in common ravens and other birds that, in turn, alert eagles. Like Paula’s bait, it must be wired to keep it from being dragged off by other animals. The camera should be oriented to the north because that ensures that the sun is to the side or behind the camera, thus preventing white photos. The study is run from January 1 to February 15, and we are hoping to find a good place on our property for Paula to set up a camera.
Hunters in the United States, who first popularized the use of cameras to monitor deer presence, should feel proud of how useful these cameras have become in wildlife monitoring and conservation.
Marcia with golden eagle (photo by Todd Katzner)
Marcia Bonta is the author of nine books and over 300 magazine articles. The blog portion of this website includes her popular “Naturalist’s Eye” column from Pennsylvania Game News, reprinted here on the 1st of each month. Unlike typical blog entries, these columns are written months in advance, usually about things that happened during the previous year. Read more…
