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5.1.08

A Scentimental Journey

Researcher Luanne Johnson began studying skunks to see if they were a threat to shorebirds, and ended up finding them a fascinating subject in their own right.

One June day I arrived home to find a surprising message on my answering machine: “Hi, this is Luanne. I’m in Aquinnah and I have an orphan baby here. I’m looking for a sitter. It would mean giving him a bottle and loving him up. He’s pretty darn cute!” It was Luanne Johnson, Island skunk whisperer, who has been researching skunk habits and habitats since 2004. One of her study subjects – a mother – had just been killed by a dog, and since Luanne knew where the den was, she had gone to rescue the offspring.

When I first heard that Luanne, whom I’d met when she was doing field work with schoolkids, was purposefully seeking skunks, I was curious to know more: about what skunks were really like and about someone who would actually choose to study them, putting herself directly in harm’s way. When she invited me to tag along, the untouchable caste of the animal kingdom gained not only faces, but names too. (I didn’t get to care for the baby though, because Luanne put it in with another mother skunk that adopted it – something I wasn’t about to do.)

Luanne, forty-two, is the kind of wildlife researcher who is willing to wander through tick-laden bushes chasing skunks for twelve hours at a stretch, through the middle of the night. She is like a Jane Goodall – who was one of Luanne’s early inspirations. She even resembles Jane, with blond hair pulled back in a ponytail, an open direct gaze, tremendous drive, and a straightforward way of talking.

As a child in northern Indiana, Luanne watched nature programs on TV, looked at the birds in her backyard, and visited the zoo often. After getting her undergraduate degree in zoology, she took care of a range of animals in the forest and desert biomes of the Indianapolis Zoo – from Siberian tigers and pandas to snakes and iguanas. Later, she was a natural history guide for an ecotour company in Alaska.

“There’s not much of anything in the animal world I can’t take care of, no animal I can’t figure out if it’s healthy,” she says.

Luanne’s first love actually is birds. Beginning in 1992, when she first came to the Island, she started working as a shorebird biologist for The Trustees of Reservations, and in 1993, with Tom Chase of The Nature Conservancy, she created environmental education programs in the schools. It was her desire to find the cause of nesting disruption in the Island’s piping plover, least tern, and oystercatcher populations that eventually led her to skunks, the most common omnivore predator on the Island.

Luanne, who lives in West Tisbury, made the skunks the (unwitting) participants in her doctoral study through Antioch University New England in Keene, New Hampshire, which she began in 2002. She will receive her doctorate in environmental studies with an emphasis in conservation biology. Now, she’s in her fifth season of a field study about the lives of individual skunks at Dogfish Bar in Aquinnah, Wasque and Norton points on Chappaquiddick, and Long Point Wildlife Refuge in West Tisbury, and expects to defend her doctoral thesis in 2009. She has tagged 141 skunks; of those, she has collared 50 with radio transmitters, of which she has established the home ranges of 35. She needs to locate a skunk 30 or more times over a period of two months to several years in order to establish its range, and needs 200 contacts with it to understand what it eats.

In her thesis proposal Luanne wrote, “Understanding the role of skunks in coastal food webs is important to understanding skunk population dynamics and behavioral ecology in coastal landscapes.” People point the finger at skunks as a cause of the diminished shorebird populations, and while they’re known to eat these birds’ eggs, there is no proof – anecdotal or otherwise – that they eat the newly hatched young. Her study aims to establish the home range, diet, and retreat and den sites of the coastal skunk population for the purpose of creating more effective trapping and management strategies that will benefit the shorebirds.

Luanne spends the months from May to September tracking skunks most nights, finding their resting places during the day, and crunching data in spare moments. The rest of the year, she checks on the skunks sleeping in their dens, sets traps when the weather warms, writes grant proposals for money to support her study, and works her paying jobs: administrative assistant at Vineyard Tax Matters in Tisbury, caterer, and adjunct faculty at Antioch’s master’s program in New Hampshire.

In search of skunks

The first time I went out skunking with Luanne was an early April morning when the sun was still so new to the day that a knee-high scrub oak cast a shadow six feet long across the open moors at Wasque. A heavy frost was visible on the patches of grass the sun hadn’t yet reached. We were going out to check the traps (giant versions of Havahart mouse traps) that Luanne had set the night before. She was at the start of her season and needed to catch some skunks to collar with radio tracking devices.

At our first stop in some pines near Poucha Pond, a disgruntled crow huddled in the back corner of a trap. Luanne’s skunk bait – potent smelling cat food, peanut butter crackers, and sponges soaked in sardine oil – sometimes catches other critters. Leaving there, we continued on to Wasque Point, where Luanne had set traps in the dunes.

Luanne says skunks are highly individual and have very different personalities – some are more easygoing, others are more aggressive. “Skunks let you get close; they know who they are,” she says. “People say that skunks are stupid, but they’re not – they’re just well-equipped.”

When she approaches a trapped skunk, she moves slowly, crouches at its level, and talks softly, all the while assessing its response. If the skunk is lounging on a pile of debris at the back of the trap, she’s not too concerned about possible combative behavior. If the skunk arches its back with its tail in the air when she gets close, it’s giving a first-level warning sign. The next level is foot stamping or lunging, and then beyond that, the skunk will show its backside, tail raised with anal scent glands opening and closing – at which point it’s best to flee.

When we found our first trapped skunk, Luanne went back to her car to get the necessary equipment: PIT (passive integrated transponder) tag, radio tracking collar, syringe, measuring tape, and scale. The skunk appeared to be sleeping, so we approached slowly in order to wake it while keeping upwind in case we startled it into a defensive response. Talking softly, Luanne reached toward it with a sedative-filled syringe taped to the end of a four-foot-long jab stick. She maneuvered the stick into the trap and gave the skunk a shot – which woke it right up! It settled down a bit as the sedative took effect, but then it lifted its head and gave a halfhearted stomp in our direction.

Only once has Luanne ever been sprayed – it was by a trapped skunk – and it happened with no warning at all. The night before had been unexpectedly cold and rainy; usually she won’t trap if a night locked up means misery for the skunk. She says, “They don’t like the rain; they get crabby.” She could tell this particular skunk was irate but before she even got close, it flipped over, almost into a handstand, and sprayed her with a direct hit. Skunks can spray either a fine mist – if the danger is nonspecific – or a directed stream up to fifteen feet if there is a definite target. She said she was like a gunshot victim. Her hands flew up and she yelped, “I can’t believe you did that!”

Luanne gave another shot to our trapped skunk, because in order to attach a radio collar it needed to be out cold. Usually one or two shots of sedative will do, but this skunk was still active. As she carried the trap to the bluff above the beach, the skunk was still busy sniffing. “That’s how they see the world.”
After a third shot, Luanne reached in, lifted the skunk from the trap, and wrapped it in a towel. She applied some lubricant to its eyes, because skunks don’t blink when they’re drugged, and put it in a cloth bag to weigh on her Pesola scale. These simple hanging scales can weigh anything in a bag, from a bird to a polar bear. This skunk weighed 2.15 kilograms (4.74 pounds) – a large skunk for early spring. He had long claws and measured 77 centimeters (30.31 inches) from nose to tail: probably a second-year skunk.

With each skunk she traps, Luanne inserts a microchip under the skin so if she ever catches it again, she’ll know which skunk it is. After scanning this one and finding no reading, she used a 12-gauge needle and inserted the PIT tag – a quarter-inch long, glass-encased microchip – and buckled on a radio collar.
Luanne names the skunks in her study after people she knows – for easy reference – and she named this one Sidney, after my husband, and handed him to me wrapped in the towel. Luanne said, “Before, I didn’t like skunks because they ate all my plover eggs, but I never thought they’d be this cute. They have a face that’s hard not to like.” I agreed that Sidney did have a very sweet face.

We left Sidney under a pine tree in the woods, wrapped in a blanket to stay warm until his autonomic system started working again. Luanne would go back later to retrieve the blanket and warn the builders at a nearby construction site not to kill Sidney if he wandered over before he became fully alert. As a scientist, she knows she’ll lose some study animals – mostly to death by car, distemper, and other diseases or parasites – but she tries to make sure they don’t come to harm as a result of her work.

Every day during the research season, Luanne follows the radio-collared skunks to see what they’re up to. She learned radio telemetry during the five years she worked at the Palila Restoration Project in Hawaii, studying the factors limiting the recovery of this bird population. Using a six-prong antenna, she listens on her radio for a skunk’s particular signal, and then, like in the children’s game of hotter/colder, she heads in the direction of the intensifying beep. Sometimes she has to drive around with the antenna held out the window of her truck to find a skunk, but most are in the same area where she first found them.

Study results to date

The size of the skunk population has always been tied to the activities of humans. Skunks were present on the Island from after the last ice age until the early 1900s when they disappeared, probably due to over-trapping for their pelts, used in the fur trade, and to poisoning. Also, the Island was largely unvegetated because of sheep grazing, so skunk habitat was limited. For sixty years there were no skunks on the Island, until the 1960s when they were reintroduced – accidentally or not, as skunks were popular as pets at that time.

There is no sure way of knowing how many skunks are on the Island now – Luanne guesses there are between one and three thousand. She knows from her study that there are regularly about a dozen skunks that live in the one-mile-plus stretch of Dogfish Bar, but Oak Bluffs, because of all its restaurants, probably has four times as many.

Sometimes tracks show that a skunk has gone right past one of Luanne’s baited traps. They have different tastes – salty food appeals to some, others like sweets – or a skunk may have been trapped before and that’s why it doesn’t explore the food there. On the beach, skunks eat mole crabs from the sand, birds’ eggs, dead things in the tidal wrack line, and apple cores and other leavings from people’s picnics. Skunks are mainly insectivores, but they also eat mice and voles, and wild fruit like beach plums and blueberries. Humans unintentionally contribute birdseed, compost, and the contents of garbage cans to skunks’ diets too.

“Skunks are very highly motivated by any food sources we provide. People think it’s because we have no predators that there are so many skunks, but it’s not. It’s because there are a lot of resources,” Luanne says. Skunks respond to resource availability: If there is more food, mothers will have bigger litters. Luanne thinks there are far fewer skunks now than fifteen or twenty years ago, partly because of the landfills closing. With the lag time of three- to five-year life spans, the population may have taken this long to decrease to its present levels.

Besides the food that humans unintentionally provide, skunks benefit from the fragmentation of habitat. You could call skunks a marginal population because they benefit from the edges created by the kinds of neighborhoods that have sprung up here in the last thirty years: houses with lawns and woodsy buffer areas around them of twenty-five to fifty yards. The lawn provides grubs, whereas the buffer area provides shelter.

Skunks are blamed for the disappearance of ground birds, but before the Island’s suburbanization, ground-bird nests were farther from the edges of woods and therefore less likely to be plundered by skunks. Luanne points out, “These species have been living with each other a long time. It’s the effects of humans that have tipped the balance in favor of skunks. We influence what species thrive and that influences our quality of life and things like if the ponds are clean.”

Occasionally, a skunk will never return to the beach where Luanne first trapped it, but instead spend the rest of the summer miles away, or turn up in some unexpected place. Skunks won’t willingly swim, but they can cover great distances on land. Luanne says, “They’re like little Sherman tanks when they want to go. I have to run to keep up with them.” The males, especially, are big dispersers. One May, Luanne collared two males at Wasque, and a few days later, they were gone. She looked all over Chappy, and finally two months later, she found one by the Bochs’ house not far from downtown Edgartown. It had walked the beach all the way across Norton Point and then the couple of miles into town.

Skunks are mainly solitary foragers, but Luanne believes they do have a social structure that’s not generally recognized. She thinks a bull male dominates an area and is intolerant of equal males, which is perhaps why one male dens for the winter with up to eleven females. She is using cameras at den sites to try to find out what happens to all the other younger males in the winter, whether some of them den together.

Luanne says skunks have friendships too. She found two females who were trapped in the spring in different places. After spending the summer on their own with their kits, she always found them together throughout the fall, and then they spent the winter with each other between two different dens. Luanne thinks matriarchal groups may den together in the winter.

Luanne would like to continue doing wildlife research on the Island after she gets her degree, and she hopes to pass what she has learned on to other people, like those drawing up the Island Plan, organized by the Martha’s Vineyard Commission. She thinks outreach and education are important and says, “People separate themselves from the natural world. They say, ‘This is my home and that’s nature.’ So when skunks come knocking, people go: Ah, the plague is visited.” Getting school-age kids involved is vital in educating the public. Luanne is sharing some of her research with kids via Ruff Ruffman, cartoon dog host of the PBS children’s science show Fetch in an episode to be shown this fall, and in a nature documentary (as yet unscheduled) for the PBS show Nature.

Although Luanne is driven to learn about things like the secret lives of skunks, she is also happy to sit and see who visits her bird feeder. Watching birds and animals is a kind of obsession. “People ask, ‘Don’t you get bored?’” She says, “How could that be boring? They never, ever do the same thing.” While watching and listening, she says, the subconscious picks up on the subtle sounds in nature. A birdcall changes, an animal moves or stays still. “When you know what the baseline rhythms sound like, then you know when something is coming.” The five senses are engaged and then, “we know the way we’re supposed to know.” Luanne says, “It reminds us who we are.”

A year in the lives of skunks

Early spring:
The female digs her den, and after gestating 59 to 77 days, the kits are born in late April to mid-May. Typically there are 4 to 6 babies. When the kits are born, they’re blind and naked, but their stripe pattern is visible in their skin. If there are not enough resources to feed the kits, she may eat them. Also, a male may come along and eat them.

Late spring and early summer:
Kits nurse for 7 to 8 weeks, then begin to follow their mother from the den. They’re dependent on her for 8 to 12 weeks, until she abandons them. Males continue to be a threat to the kits when they’re small. Rural legend speaks of 3 to 4 litters per season, but there is only one. The mother needs to begin to put on weight to survive the winter.

Late summer and fall:
The main job is to eat and gain weight. In October and November, skunks use dens when temperatures fall below 45 degrees, and some nocturnal activity continues.

Winter:
A group of female skunks will share a den with one male. Some younger males may den together. Skunks don’t hibernate and are easily awakened. If the temperature is above freezing, they become active, although for shorter periods. They breed in February or March. Females ovulate after copulation; the mother can delay implantation of the eggs if the conditions are not right. Fat stores are used as the winter continues, and skunks lose half to two-thirds of their body weight before spring.

Reducing the human impact on skunks

Luanne Johnson attributes the Vineyard’s large skunk population to the resources we provide. To help reduce conflicts around your home as well as help limit skunk impacts on beach-nesting birds, she’s come up with these tips.

Limit food you provide both at the beach and at your home (even if you live two miles from the beach):

Skunks scavenge for leftovers at the beach, so never leave or bury any food scraps. When fishing, don’t clean your catch on the beach or leave remains in your yard. Keep garbage cans tightly covered, and fence compost piles. Don’t leave pet food outside or feed skunks. Use a seed catcher under your bird feeder, and keep your birdseed securely stored. If you are building a new home, consider native plants and grasses instead of a lawn, because skunks love the grubs and insects lawns provide.

Limit shelter you provide:

Keep the spaces under your house, deck, shed, woodpile, chicken coop, boat, and other structures clear of debris that can provide hiding places. Block access by burying short fencing or wood so that skunks can’t easily crawl under them (be sure you aren’t blocking a skunk in). Remove junk piles and piles of branches. At beaches, remove buckets and fish tubs that wash up; they provide easy dens or retreats.