Herd in the Shrubs
Two different means of population control of wild horses on Assateague Island National Seashore are conducted by the two governing organizations.
The barrier islands along the eastern shore of the United States have been used for grazing domestic livestock for centuries. The horses of Assateague Island are descendents of the working horses used for mainland farms.
These “horses in pony bodies” roam the island marshes and beaches off the Maryland and Virginia shoreline. The National Park Service owns and oversees the herd living in the Maryland portion of Assateague Island. The Virginia portion of the island is part of Chincoteague National Wildlife Refuge and the horses are owned and managed by the Chincoteague Volunteer Fire Department.
Just as control of the herds is divided by state lines, management of the herds differs as well.
ASSATEAGUE HERD MANAGEMENT
The National Park Service (NPS) treats the horses like wildlife” says Carl Zimmerman, Management Assistant for Assateague Island National Seashore.
In 1968 the NPS bought the original 28 horses living on the Maryland portion of the island at that time. The herd thrived during the 70s and 80s, reproducing at about 15% per year. Their numbers were growing so dramatically the NPS become concerned that the population could disrupt the island’s ecosystem. So the NPS embarked on a remedy to control the population without disrupting the herd dynamics. The study originally focused on the stallions, but what evolved was a contraceptive vaccine for the mares’ reproductive system.
Allison Turner, a biological technician, has been involved with the management of wild horses at Assateague Island National Seashore in Maryland for 20 years. In the spring and summer, Turner uses a modified rifle to shoot the mares with birth-control loaded darts. The vaccine she uses is called Porcine Zona Pellucida, or PZP, and comes from a protein found in pig eggs. When it’s injected in any female animal other than a pig, it temporarily blocks fertilization.
According to Zimmerman, the vaccinated mares do not lose their place in the herd hierarchy, their behavior shows no noticeable change and there are no signs of adverse health effects.
“What came from this small eco-cycle study was groundbreaking; The contraceptive developed and tested here at Assateague is now in use for other species of wildlife for population control around the world,” says Zimmerman.
The horses on the Maryland portion of Assateague live along a 22-mile strip of sand, marsh and coastline. They can roam freely on the 8,000 acres.
Population surveys are conducted six times a year; details on the herds have been recorded for 5-6 generations. “We know everybody out there” says Zimmerman. Twice a year a staff biological technician tracks the horses down and targets all fillies and mares of reproductive age. Zimmerman says they like to keep the horses vaccinated until they are 5 or 6 years of age and then they are allowed to breed naturally at least once in their lifetime.
The rest of life is left up to the horses. When it’s hot, they move to the shoreline and hang
free range ponies
out with the beachgoers and campers. If you are lucky you will catch them cooling off in the surf. They are also escaping the insects, which are voracious on this barrier island. Recently the NPS hired a full-time staff person to help the volunteer Pony Patrol in keeping the peace between horses and visitors. They shoo horses out of the campgrounds and off the roads and keep beachgoers away. The horses are not fed, sheltered or vetted for illness. Except for the birth control, they live and die naturally.
THE CHINCOTEAGUE WILDLIFE REFUGE
The Chincoteague ponies live within nearly 1000 fenced acres and the herd is not to exceed 150 individuals. The Chincoteague Volunteer Fire Department owns the herds and leases the fenced land on the Chincoteague Refuge for the horses to graze.
Three times a year a roundup is held. “Our ponies are micro-chipped,” says Fire Department Secretary and Public Relations officer, Denise Bowden. “As the vet is working on each individual, the scanner slides over the chip to identify the pony, and the meds he administers to each pony are recorded.”
Bowden adds, “We check their teeth, their hooves and for any obvious scrapes or cuts.” They also vaccinate for West Nile and Equine Encephalitis.
There is no form of birth control practiced in the Chincoteague herds. The offspring are sent to new homes via an annual auction. This undertaking by a group of volunteer firemen and women keeps the fire house in operation, and pays for the ambulance, fire trucks and other life saving equipment. The townspeople pay no fire tax; they just have to put up with 40,000 visitors the last week in July craning to watch the wild horses parade through town to the fairgrounds during the event’s festival atmosphere.
In 2011, 69 youngsters were sold. Some of the horses are auctioned and paid for but sent back to the island to maintain healthy herd size. This buy-back plan brought the highest bid of $6700 from the “Buy Back Babes.” The reasoning for spending so much on this particular buy-back was explained by BBB spokesperson, Jean Bonde: “The foal is the fourth generation of the lineage that the BBB’s had bought throughout the years.” The purchased foal was named Splash of Freckles after its mother, Freckles, a pony the Buy Back Babes purchased in 2006.
Over the past 20 years, the Chincoteague wild ponies’ lactating mares have been treated occasionally for hypocalcaemia, a calcium deficiency, which can be life-threatening to nursing mothers. To help prevent this, the volunteers put out calcium blocks on the beaches and in the holding pens.
One ecosystem, two methods of dealing with a potential imbalance from non-native species.
Karen Tappenden is co-publisher of Holistic Horse magazine.
The Assateague Ponies by Ronald R. Keiper, Tidewater Publishers 1985.
Check out the 2010 Chincoteague pony swim video here...