Researcher finds much to learn about skunks
A skunk ambling across a yard or along a dark Vineyard roadway or beach is a common sight. But while most Islanders and visitors are familiar with the skunk's unmistakable odor, most people know little about how the animal lives.
The exception is Luanne Johnson, a doctoral candidate at Antioch University New England. She has been tracking the Island's skunks since 2004 to get information on their behavior and population patterns. One goal of her research is to determine the impact coastal skunks have on nesting threatened or endangered shorebirds, including piping plovers, least terns and American oystercatchers.
Ms. Johnson said she selected coastal skunk ecology as the subject of her doctorate after many years of observing and tracking birds in Hawaii. "When you're doing a PhD, you want to do something that people want to see done, that you think you can do and be interested in for a lengthy period of time and that's fundable," she said in a recent interview with The Times. Because there was little or no research on skunks in coastal habitats she expected that there would be interest in the subject that extended beyond her own.
Luanne Johnson measures a skunk.
Her work takes her out in the field six days a week in the spring and summer months. Much of her attention is focused on Dogfish Bar in Aquinnah, Norton Point and Wasque Reservation on Chappaquiddick and Long Point Wildlife Refuge in West Tisbury.
Long before the sun rises, the slender biologist, well tanned from many hours spent outdoors, sets out to check traps she has set in her three target locations. When she finds a trapped skunk, Ms. Johnson sedates it with an injection administered by means of a thin pole topped with a syringe.
After the injection, she only has 20 minutes to work on an animal before it revives. She uses her time effectively. She attaches a tag to the skunk's tiny ear, fits it with a radio collar that transmits a signal that will allow her to track its movements and takes various measurements.
Asked about the Island's skunk population, she pauses to do calculations in her head. She estimates that there are between one and three thousand skunks on the Vineyard.
Of those, Ms. Johnson has tagged 120 and fit 49 with radio transmitting collars since she started her study.
Once skunks are trapped and released, Ms. Johnson keeps track of each animal's movements. The radio collar emits a series of crisp blips that she can detect on a portable radio. Using an antenna, she follows the blips until they get louder, letting her know she is in close range of the animal. Once she finds where the signal is coming from, she uses a hand-held computer linked to a GPS unit to record the animal's location.
A skunk is outfitted with a radio collar.
Countless hours of tracking and monitoring have provided Ms. Johnson with a glimpse into the secret lives of skunks. She has learned that even though skunks are most often seen ambling along, they can travel quite a distance, covering up to two miles on the beach in a given night.
To emphasize that point, she told of one skunk she trapped on the beach at Long Point and fitted with a tracking device. Later she could not receive a signal on her radio.
When she found the same skunk in a trap a week later, she took the opportunity to learn more. "I let her out of the trap, and I followed her home," she said. "I thought, 'okay, she's going to take me wherever she lives.' And she took me almost two miles down the beach. One-point-seven miles we traveled to Oyster Pond where her den was."
Since she was nursing kits, young skunks, she returned to the same den each night. Skunks without kits, however, sleep in different spots each night during the summer, making their homes underneath shrubs, old boats and decks. "They're moving around a lot, and a lot of places kind of function as little skunk motels where skunks will come and go," Ms. Johnson said.
When winter arrives skunks settle down in ground dens, which are chambers six feet underground that house a male and as many as 11 females. Even though there haven't been many studies done on the social aspects of winter denning, Ms. Johnson has a theory. "My suspicion would be that it's some sort of matriarchal line of females, and a male sort of secures rights to those," she said.
While it may appear that the Vineyard has a surplus of skunks compared with mainland communities, Ms. Johnson said that is not the case. "I don't think we have more skunks, but we have lots of resources," she said.
Ms. Johnson often finds that skunks on the beach at night will abandon their usual diet of insects and small rodents to feast on scraps of food left behind by careless beachgoers.
She said that the best way for homeowners to avoid a seasonal skunk problem is to reduce available resources by securing garbage cans, not leaving trash on the beach and raking underneath piles of wood and house decks.
It's especially important to not leave food behind on the beach. The skunks will wander onto the beach looking for human food and eat that along with the eggs of nesting shorebirds that people are trying so hard to protect.
Skunks are natural predators and affect the number of birds by stealing eggs. "They don't seem to go out and hunt them methodically. They're just ambling down the beach, and they bump into them and then they'll eat whatever's in front of them," Ms. Johnson explained.
By the time her dissertation is finished in late 2008, Ms. Johnson hopes she will have learned whether or not skunks also kill shorebird chicks. "Neither I nor my field assistants have ever seen them take a chick, so if they do take chicks, they certainly do not do so on a regular basis, or we would have seen it by now," Ms. Johnson said.
Ms. Johnson plans to organize and analyze the data she has been collecting since April. For now she will rise before sunrise and go to work.