6/7/10
Loons imperiled by spill
Region’s symbol could be devastated by oil impacts on winter range
By Marshall Helmberger
M. HelmbergerNorthern Minnesota loons may be living on borrowed time. They are likely to face extremely hazardous conditions when they return to winter range on the Gulf of Mexico this fall.
The unprecedented oil spill in the Gulf of Mexico may seem a long way from the lakes of northern Minnesota. Yet the effects of that extraordinary environmental disaster will find their way to the region, and the impacts could be apparent as early as next spring.
Residents of northern Minnesota’s lake country could well find their lakes considerably quieter than usual next year, fallout from the dramatic loss of bird life that is inevitable in the wake of the largest oil spill in the nation’s history. Among the most vulnerable species is the one most identified with northern Minnesota, the common loon.
Minnesota is home to by far the largest population of common loons in the lower 48 states, with an estimated 12,000 adults in the state during the summer months. And while Minnesota’s loon habitat remains intact and healthy, the state’s loon population could be especially vulnerable to the effects of the oil spill. That’s because a large percentage of Minnesota’s loons winter on the Gulf Coast.
According to Pam Perry, a loon expert with the DNR’s Nongame Wildlife Program, the bulk of the state’s loons are believed to winter in the Gulf, along the coast of Florida. While Florida beaches have yet to see any major impact from the spill, the expanding spill is already encroaching on near-shore areas in and along the Florida panhandle.
Recent history has demonstrated that loons are extremely vulnerable to the effects of oil spills. An estimated 400 loon deaths were documented in 1996 as a result of an 828,000 gallon oil spill off the coast of Rhode Island. A 2003 oil spill in Buzzards Bay in Massachusetts, was estimated to have killed 200 loons. The Exxon Valdez spill killed an estimated 375,000 seabirds and other waterfowl and according to the U.S. Fish and Wildlife Service, loon populations in that area had yet to recover from the effects of the spill as much as 15 years later.
Yet even the Exxon Valdez spill is likely to be dwarfed in comparison to the ongoing spill in the Gulf. The blown- out British Petroleum well is believed to be emitting between 750,000-1 million gallons of oil per day. That spill is now in its seventh week, and given the failure of recent containment efforts, it could well be months before the leak can be plugged. BP is now indicating it may have a relief well completed by August. That well should relieve the pressure at the existing one long enough to allow the company to plug the hole created during the April 20 explosion aboard the drilling rig Deepwater Horizon.
The Gulf spill is already estimated to be nearly four times as large as the 11 million gallon Exxon Valdez spill in Alaska in 1989, which had been the largest on record in the U.S. prior to this year. If the well continues to discharge oil until August, the BP spill could surpass 100 million gallons and create an unprecedented environmental crisis just as hundreds of thousands of North American waterfowl, including loons, terns, white pelicans, cormorants and numerous species of ducks and geese are descending on the Gulf for the winter.
“We really don’t what the impact will be,” said Perry. “This is going to be a huge disaster for a long time, but right now, we’re in a wait and see mode.”
Spill could take biggest toll on immature loons
While Minnesotans focus their attention on the impact to loons currently residing in the state, a future generation of Minnesota’s loons is most at risk, and has likely already been harmed by the spill. That’s because, unlike many birds, loons don’t reach maturity until age three or four. Until that point, many don’t return to northern lakes, remaining, instead, in the Gulf region year-round. Exactly where Minnesota loons spend their time isn’t entirely clear, said Perry. “No one studies them down there. Pretty much all they do is bob out in the waves and eat fish.”
That is behavior that has already put many two and three-year old loons at risk from the oil spill and its effects. And Perry worries that oil isn’t the only threat to loons. She said she is especially concerned about the effects of BP’s widespread use of dispersant chemicals, which emulsify the oil and make it more likely to enter the food chain. Once that happens, the concentrations of the toxic chemicals will be amplified as they accumulate up the food chain, much as happens with mercury, DDT, and other environmental toxins.
Recovery could be slow
While many species of birds and other wildlife can respond quickly to population declines, some species, like loons, have shown they can be slow to recover from decreases in their numbers. That’s true, in part, because loons are slow to mature and because they rarely raise more than one or two chicks per year. Loons can live about thirty years in the wild, and such longevity allows loons to maintain their populations even with a slow rate of reproduction. But when an environmental disaster wipes out a significant number of loons, a slow breeding strategy means recovery can take a long time.
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