Wolves
Change an Ecosystem
Coyotes
in Rock Creek ParkCapital Coyotes
by Howard Youth
On a cool late March morning in Rock Creek Park, I tramp along a slope thick with oak leaf litter, following khaki-clad Ken Ferebee over spring beauty wildflowers and through bud-swollen spicebush branches. The park preserves 1,755 acres, mostly in Northwest Washington, D.C.; as its natural resources management specialist, Ferebee keeps an eye on plants, the growing deer herd that damages them, box turtles, and other creatures. He's been on the job here since 1991, but just last year a new animal crossed his radar—one that intrigues not only him and me, but the entire D.C. metropolitan area. The coyote's come to town.
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| Coyotes, once emblems of the Wild West, have moved eastward and now live in Washington, D.C. (Gary Kramer/USFWS) |
Ferebee takes me to the top of the wooded ridge and points to four gnarled fallen trees that lie parallel to each other like herring bones. At one end of each bulges an orange mound of soil left around the trees' now-rotted roots. "I've been finding dens around these root balls, in secluded, protected types of situations," says Ferebee. Stepping over the log closest to us, I easily see what Ferebee promised he'd show me—a two-foot-wide hole dug under the log, between the root ball and the base of the trunk. "This looked pretty active when there was snow on the ground," Ferebee tells me, describing how he found what were most likely coyote (Canis latrans) tracks in the snow and had noticed freshly dug soil all around the den site two months before. The tunnel jogs left and out of sight soon after plunging beneath the ground. Ferebee then shows me a hole near another fallen tree 15 feet away, which he believes is an exit.
"I've not seen this one before," he says, kneeling down for a better look at a smaller hole dug under another nearby log. "This could be a fox den or a [coyote's] work in progress." We talk about the park's deer concerns—the 36 reported deer-car collisions in 2004 and the large herbivores' impact on herbaceous plants—and the coyote, a predator that has been sighted in or near the park almost 30 times in less than a year and one that could also change this urban forest.
Will coyotes solve the deer problem? How will they affect local wildlife populations? Will they kill many area pets? These and many other questions about the animals' biology and adaptation to the eastern United States remain unanswered. But now that coyotes are here, Ferebee and others are on the lookout and learning more every day.
March of the Prairie Wolf
"Coyote. Prairie Wolf. Common on the Great
Plains, burrowing in the ground. A vagabond, dog-like
animal, 'half bold and half timid, yet lazy all through.'"
In 1929, David Starr Jordan thumb-nailed the coyote this way in the 13th edition of his Manual of the Vertebrate Animals of the Northeastern United States. At the time, coyote sightings stretched as far east as Illinois. Today, the "vagabond" lives throughout the United States except in Hawaii, through much of Canada, and down to Panama. Following the coyote's incredible expansion, which is one of the most rapid of any carnivore, it certainly seems anything but lazy.
In fact, if you want to anthropomorphize the coyote, you might call it an over-achiever. "The successful colonization by the coyote of most of North America…over the past 100 years is unparalleled by any other species of terrestrial mammal in recent history," writes Canadian Wildlife Service biologist Gerry Parker in his book Eastern Coyote: The Story of Its Success. Two ingredients made the coyote's spread eastward a success over the last century: The hacking down of eastern woodlands left more open areas and forest edge for coyote habitat, and the virtual annihilation of gray wolves (Canis lupus) in the East and Northeast and red wolves (Canis rufus) in the Southeast eliminated two of the coyote's most formidable competitors.
Washington, D.C., received its first coyote reports very late in the game. In May 2004, a motorist reported seeing one on the side of a road in Rock Creek Park. Coyotes had already reached northern Virginia, Maryland, and Delaware—among the last places to report them—in the 1980s and 1990s. But that's not to say that coyotes weren't around before then. Hunters know that coyotes are not easy to pin down. Nighttime yips, barks, and howls often confirm their presence, as do findings of coyotes hit by cars. But no one can say for sure when the first coyote paws crossed state lines.
In the past, some coyotes were kept as pets or used as quarry to train hunting dogs, which may explain the origin of a solitary coyote shot in Cecil County, Maryland, in 1961. In the 1969 Department of the Interior report Mammals of Maryland, biologist John L. Paradiso wrote: "The question naturally arises as to how a coyote reached this eastern locality. It is, of course, impossible to say definitely. The animal probably escaped from captivity. Or it may represent an extreme eastern extension of the geographic range of coyotes."
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| A camera trap in Rock Creek Park caught this coyote investigating the carcass of a deer that was killed by a car. (Ken Ferebee/NPS) |
These days, the coyote stands alongside the eastern cottontail (Sylvilagus floridanus), white-tailed deer (Odocoileus virginianus), and raccoon (Procyon lotor) as a familiar mammal of eastern forests and fields. As coyote numbers grow, more and more people are seeing them during nighttime drives, or even in their backyards. Cameras don't lie, and biologists' motion-sensitive cameras help mark the coyote's advance. When Zoo Conservation and Research Center (CRC) veterinary technician Lisa Ware checked out the digital camera trap she'd set in hopes of recording a bobcat she thought was denning on the facility's property, she found something quite different. "Catching a coyote on the camera trap at its present location was a surprise. I have the camera set along a frequently traveled gravel road that services one of the hoofstock barns. This road is pretty much in the heart of the campus." Over the past few years, coyotes have turned up infrequently at CRC. The bobcat vanished from the area after the coyote photos were taken. Ware says, "My suspicion—hope—is that the cat detected the increased presence of the coyote and has shifted her denning site." In other areas such as Florida and Maine, bobcats share common range with coyotes and researchers suspect that they coexist but avoid each other's core areas of activity.
Although they're around, you may be disappointed if you go out looking for coyotes. Rob Gibbs, a natural resources manager for the Maryland-National Capital Park and Planning Commission, goes out from time to time and plays a tape of rabbit distress calls to attract Maryland's newest predator. "My calling technique must be okay because I'm calling in foxes like crazy, but no coyotes," he says. "Just knowing the persecution they've faced and knowing how they survived, obviously they learn quick and don't make the same mistake twice."
Among sheep raisers and other ranchers out West, coyotes are as reviled as cockroaches in a New York City apartment. "It may be spiritually rewarding to hear the chorus of coyotes at day's end," writes Parker in Eastern Coyotes, "but that twilight song may sound different to the farmer who lost a prize ewe to those same coyotes the previous evening."
This gives perspective to the ongoing campaign against western coyotes. Hundreds of thousands are trapped, shot, or poisoned each year, apparently with no overall effect on their population, although local declines have been noted. Some researchers found that high mortality actually increases coyote litter size.
On wide-open western rangelands, the coyote will continue to compete with livestock raisers for their animals—in essence, for our food. But that's not to say that the coyote is not foiled in some places. Some ranchers swear by trained guard dogs or burros that hang out with sheep flocks and drive off coyotes on sight. Others pay closer attention to their fence lines, repairing holes or installing electrified lines that repulse curious coyotes. In many parts of the East, livestock sleep in sheds or barns at night, a practice that greatly reduces chances of coyote attacks. At a local level, livestock attacks have yet to become commonplace. "We've had coyotes in the state now pushing 20 years," says Steve Bittner, a game mammal section leader at the Maryland Department of Natural Resources (DNR). "There's been some livestock killed. A little bit. Not a lot." Each year out West, however, coyotes kill thousands of sheep, goats, chickens, turkeys, and some calves and hogs, too.
Keeping Coyotes Wild
On the suburban scene, one thing local residents need
to learn is that coyotes may attack pets their size
or smaller. "We have problems with dogs off leashes
in the park," says Ferebee. "There might be
some incidents because of that. Coyotes will defend
their dens and young." In 2004, two mid-sized dogs
were probably attacked by coyotes after their owners
let them off their leashes despite the park's leash
rule.
Long unchallenged, except by occasional clashes with other cats or dogs, area house and feral cats may already be changing from predators to prey. "In this area, there are a lot of feral cats," says Gibbs, "which tend to disappear when coyotes reach an area."
"It's possible—probably even likely—that posters you see on telephone poles for missing cats could be related," adds Fairfax County wildlife biologist Earl Hodnett. Just ask Michael Soulé, professor emeritus of the environmental studies department at the University of California at Santa Cruz. He grew up in coyote country and has studied western coyotes for years. "The smart cats avoid coyotes by staying home, up on the rooftops or in the trees, and the other ones get eaten," he says, adding that as a child he lost almost half of his cats to coyotes.
"Right now, not many people are seeing coyotes," says Gibbs. "When they do, the coyotes are running away. We need to start educating people about the basic stuff: Keep the trash tightly closed. Don't put out any pet food. We need to keep them as wild as possible. As long as they are afraid of people, they're not going to be a problem." Hodnett, Ferebee, and many other wildlife officials echo Gibbs' advice. Coyote attacks on people are rare, but where they have occurred, such as in the Phoenix, Arizona, area and in some western parks, the animals involved are usually accustomed to feeding on food or trash in backyards.
How will coyotes affect wildlife? In snowbound northeastern forests, coyotes can be major predators of white-tailed deer, dragging down healthy adults in deep snow. But in general, coyotes feed mostly on whatever they come across while coursing through their habitat. With an abundance of fawns and roadkills, D.C.-area coyotes should be familiar with the taste of venison, but they are just as likely to focus their efforts on rodents, rabbits, berries, trash, pet food, and a variety of other foods. Will deer feature prominently on their menus? "I don't know if they will make a serious difference around here," says Gibbs, who spends much of his time grappling with ways to manage Montgomery County's surging deer herd. "Coyote numbers are still low. It depends. I'm taking a wait-and-see attitude, but I have my fingers crossed."
The coyote-deer association is much discussed and has even become the stuff of urban legend. "There's a rumor out there the last year or so," says Maryland DNR's Bittner. "The rumor has it that auto insurance companies are in cahoots with state wildlife agencies to stock coyotes to eat deer. This is supposed to bring down deer populations, which brings down deer collisions, which brings down insurance claims. That's not going on," says Bittner, who adds that the DNR has received coyote reports in every Maryland county over the past few years and "we've not noticed any marked decline in deer."
Smaller predators will likely feel the bite as coyote numbers grow. "I think, in general, coyotes will bring some ecological balance to natural systems by helping to control possums, raccoons, red foxes, and other mid-sized predators. That will have benefits for those animals that these animals suppress," says Martin Main, a University of Florida biologist who studies the coyote's march across Florida. Animals that may benefit from the coyote's presence include ground-nesting birds such as turkey, quail, and some ducks.
Meanwhile, Fairfax County's Hodnett hopes that coyotes will target some other large birds, namely nonmigratory suburban Canada geese (Branta candensis) that soil and nest in area parks, golf courses, and school grounds. "A large Canada goose weighs 12 pounds and a fox weighs 12 pounds," says Hodnett. "A goose pair could team up on a fox, but a [heavier] coyote would have the match tipped in its favor." Like so many other questions, the goose-versus-coyote scenario is an unknown.
At a Den Site Near You…
On average, eastern coyotes weigh between 35 and 40
pounds. That's up to twice the weight of a scrawny southwestern
coyote but half the weight, at most, of a husky or German
shepherd. Eastern coyotes may be larger than their southwestern
counterparts because the East's climatic conditions
are different and its food supplies may be more abundant
than those out West. Or, the size difference may be
due to eastern coyotes' part-wolf heritage. Genetic
testing indicates that eastern coyotes likely have a
little wolf blood they picked up as pioneer coyotes
passed through gray or red wolf enclaves in the Northeast
and Southeast. In at least some parts of the Northeast,
coyotes remain in family groups longer into winter than
those in other regions. This extended social behavior,
reminiscent of wolf pack behavior, enables the animals
to hunt deer when smaller prey is hardest to find.
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| Coyotes likely bred with wolves, like this red wolf, as they moved eastward. (photos.com) |
For fairly large animals, coyotes are masters at keeping a low profile. Few people see their brushy, black-tipped tail, the tan-and-gray fur, the large triangular ears, or the alert yellow eyes. Fewer still see the coyote dens carefully dug under logs or other debris or enlarged from abandoned fox, rabbit, or groundhog burrows.
In some metropolitan areas, coyotes live underfoot. Biologists found some sleeping under cars in the Chicago area. Coyotes den in culverts under the streets of Phoenix, beneath mobile homes, and in narrow parks snaking through heavily suburbanized neighborhoods throughout the East. One was even darted and moved to a zoo after popping up in Central Park in 1999. It probably got there after crossing a downtown bridge.
In much of the eastern coyote's range, females come into heat and mate in January and February. Coyote pairs generally do not mate for life, but may stay together for a few years. In April, following two months' gestation, females give birth to a litter, which on average numbers four to six pups. At the slightest sign of danger, pups may be moved to another den site.
By late spring, young finish six weeks of nursing, then eat food their mother regurgitates for them, followed later by solid food. Pups leave the den in mid-summer, traveling around with their parents. After learning to hunt, they help catch prey. Most juveniles strike out on their own by the end of December, although family groups in the Northeast may stay together until as late as March.
Coyotes likely use Rock Creek Park as a refuge in which to den and escape from the urban fray during the day. By nightfall, the park's coyotes—and no one currently knows how many or how few there are—disperse into local neighborhoods. The area used by a coyote for all of its activities, called its home range, varies widely from site to site. Also, breeding individuals wander far less widely than dispersing juveniles and unpaired adults. In a Florida study, ten to 15 square miles was average. In the Northeast, where food can be scarcer, home ranges are often far larger. Home ranges of dispersing western coyotes may reach 65 square miles or more. So, a coyote seen in a neighborhood one night may be denning nearby, or just wandering.
Some people feel happy knowing the coyote has settled in the D.C. area. "To be witnessing a sizeable predator coming into the area, especially in light of the work that I do with deer in the county, is thrilling," says Gibbs. "We'll see how it will work out in the ecosystem. We used to have wolves in this area. Coyotes aren't wolves but they're the closest we'll get. Something may well come back into balance."
Others aren't so thrilled. "Some people call and are outraged that we don't have programs for trapping and hunting coyotes," says Fairfax County's Hodnett. "That's what's been going on out West for years and they've not had any more success" in controlling coyote populations.
Others take a more cautious approach. "We're taking a hard look at how we're housing some of the animals," says William Xanten, general curator of the Smithsonian's National Zoo, which is bordered by Rock Creek Park on three sides. "We're concerned. There's no doubt about that, but basically, there's not much more we can do than what we do already for foxes and raccoons. We're pretty well protected at [potentially vulnerable] places. The majority of the animals in our outdoor collection are too large for foxes or raccoons or possibly even coyotes. Birds that roost outside are protected by hot wires or total enclosures," he says.
National Zoo Senior Scientist John Seidensticker grew up in coyote country, in Montana, and is skeptical that coyotes will be a benign addition to the Zoo property and adjoining Rock Creek Park. "The bottom line is that we just don't know [much about these new predators]. They are a new element to the eastern fauna. But they won't regulate themselves within Rock Creek Park," he says. "You're never going to have large-scale natural processes in this small-scale place. Coyotes will be very effective in invading surrounding communities."
Whether you love or hate them, coyotes seem here to stay, something that Ferebee and I agree on as we look down at whitish tufts of fur scattered at our feet. We're now standing beside a convenience store-sized mulch pile at the edge of the forest. "We took a deer carcass off the road and put it here, then put out a camera," Ferebee tells me. "We got foxes and coyotes on the same roll of film, so they're coexisting for now." Ferebee adds that he's not seeing as many red foxes as he used to, and when he shines lights into the park's woods to count deer, he's starting to see coyotes too.
Back at his office, Ferebee shows me the photos snapped
at the spot where the fur now sits. There's a carrot-orange
red fox peering into the camera, followed by shots of
two tawny-and-gray coyotes standing over the carcass.
The robust coyotes seem as if they've always lived in
this forest. "By the third roll," Ferebee
says, "they seemed to be a lot more wary."
Later pictures show the coyotes farther back, more hindquarters
and bottlebrush tails than anything else. But they apparently
were not giving up on the carrion, despite the annoying
flashes. "Right after we took the camera away,
the carcass disappeared," says Ferebee. "They
dragged it away."
—Contributing editor Howard Youth's last
ZooGoer article focused on Florida's introduced
reptile fauna.
ZooGoer
34(4) 2005. Copyright 2005 Friends of the National Zoo.
All rights reserved.
