ASSATEAGUE — A baby boom continued at Assateague last weekend with the birth of a new foal, the sixth of eight expected this year.
Prolific mare Gokey Go Bones birthed the new foal sometime last Friday or early Saturday and the suspected sire is Yankee. The new addition and the parents are known to frequent the area around the causeway and the heavily-traveled entry to the barrier island and residents and visitors are urged to give the young family plenty of space, especially with the parks reopening and the arrival of Memorial Day weekend.
“As always, we remind visitors everything is new to a foal,” said Assateague Island National Seashore Chief of Interpretation and Education Liz Davis this week. “New foals will learn how to interact with the environment from their mother and other members of their band. A mare will be very protective of her new foal and it is vitally important for their well-being that visitors give them and all of the wild horses plenty of space.”
Despite the temptation to visit and take pictures of the new foal, National Park Service officials are reminding residents and visitors everything is new to the foal and are reminded to keep a safe distance from the mare and her offspring. As a rule of thumb, a safe distance is defined as around 40 feet, or roughly the length of a school bus.
Each fall, Assateague Island National Seashore biologists conduct pregnancy tests on the mares among the population in and attempt to predict how many new foals are expected to join the herd on the Maryland side of the barrier island in the coming year. The results from the pregnancy tests conducted last November confirmed eight of the mares were expecting and already six new foals have been born this spring including the new addition last weekend.
In the interest of maintaining a healthy population size, the National Park Service several years ago began a contraceptive program for the mares. In almost each year since, selected mares have been injected, or darted more appropriately, with a non-invasive contraceptive called PZP in an effort to maintain the size of the herd on the Maryland side in its manageable threshold. The target range for the horse population on the Maryland side of Assateague is 80-100 and there were times over the years when the population was well north of those numbers.
In recent years, due to the contraceptive management program and the loss of some horses to old age, attrition and death, often natural and occasionally from man-made causes such as vehicle collisions, the population had dipped. According to the March census, the number of wild horses in the Maryland stood at 73. However, with the birth of six new foals this week and two more expected, the population has moved closer to that 80-100 target range.
As a result, the National Park Service’s contraceptive program has shifted to an adaptive management phase. Davis said earlier this spring that adaptive management phase will likely continue.
“Eight is the most pregnant mares we’ve had in many years, due to no contraception for the last four years,” she said. “One mare was contracepted in 2016, but none have been since then. We’re allowing mares to reproduce freely until such time as the population once again reaches the upper end of our goal range of 80-100. We look at the population dynamics each year and make changes as needed. Precise balancing of mortality and foaling is not possible because the age at death varies greatly for each horse, as does the number of mares that will foal in a given year.”