Assateague ponies set to multiply.
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Aging mares in Assateague’s herd of wild ponies recently prompted conservation and wildlife management authorities to announce a change in the horses’ birth control policies. Yes, you read that right—in order to keep populations in check and promote healthy breeding habits, the Eastern Shore ponies have been on a regimen of contraception since 1988. For almost three decades, by means of a yearly dart-gun vaccination containing a non-hormonal treatment that blocks fertilization, the National Park Service (NPS) has administered birth control to the younger mares. According to the NPS, the practice is a harmless, non-invasive means of controlling the population.
However, with many mares either already or soon becoming too old to breed, the herd’s numbers threaten to dwindle below the NPS target range of 80-100 horses, which the agency says is the range the island’s ecosystem can healthily support. “Our herd presently contains a large proportion of mares aged 20 to 33,” says Liz Davis, a wildlife education coordinator for Assateague Island. “These older mares are unlikely to foal again, so in order to refresh the reproductive population in the near future, an increase in foaling among the younger mares needs to occur.”
Hence the NPS’s decision to cease administering birth control to fillies over the age of two for the 2017 season. Davis says the measure is part of a reduction plan that has been about 6 years in the making. “The goal is to see an increase in foaling by minimizing contraception, and monitor and adjust over the years to stay within the 80 to 100 goal,” she says.
Recently, park officials collected stool samples from each of its 66 mares and mailed them to the Science and Conservation Center in Montana, where analysts will test the manure for hormone levels indicative of pregnancy and viability. Results are expected to return in January. “When new foals are born, that of course brings in more visitors,” says Assateague Coastkeeper Kathy Phillips. “From residents and tourists to all the other flora and fauna living on the Island, when the herd is healthy, it’s good for everyone… We know that the ponies are really one of the biggest attractions here and we definitely want to see them healthy and controlled.” AssateagueIsland.com