Science

Rigged Decks

Is the Gulf of Mexico a haven or a minefield for birds?

Interactive map courtesy of the FracTracker Alliance

Five years ago, after the BP Deepwater Horizon oil spill devastated ecosystems in the Gulf of Mexico, the Obama administration slapped a six-month moratorium on deepwater drilling in the Gulf. But the fossil fuels industry has since bounced back in the region, with companies like BP building new offshore oil and gas platforms—also known as rigs—that are bigger than ever. There are currently 2,674 platforms in the Gulf, says Karen Edelstein from the FracTracker Alliance, a watchdog organization that collects and publishes data about the global oil and gas industry. The structures form a steel barrier along the coasts of Mississippi, Louisiana, and Texas; every spring and fall, millions of birds migrate over, around, and through this industrial swathe as they travel between their wintering and breeding grounds. In the BP disaster’s immediate aftermath, the spill’s effects on birds were horrifically clear. Now, five years on, the physical presence of the rigs themselves, and their effect on migrating birds, is attracting increased attention.

Unexpected cargo

These towers—usually hundreds of feet tall—are built to either drill and extract oil and gas from the seabed or store collected fuel. The wide, flat rigs are like small industrial complexes, with towers and control rooms, tanks and pipes, gas flares, and cranes reaching high into the sky. The thousands of oil and gas rigs that populate the Gulf can be loosely classified as  “active” or “inactive.” Active means they’re being used to extract oil; inactive means they’re not currently being used though they nevertheless remain in place. For migratory birds, it doesn’t matter whether the platforms are dead or live; they can serve as mid-ocean rest stops either way.

“Stepping stones” in the sea

In the late 1990s researchers from Louisiana State University and several conservation groups teamed up with the U.S. government’s now-defunct Minerals Management Service and several energy companies to produce a landmark, 326-page study on oil and gas platforms and migratory birds in the Gulf. Published in 2005 by the Department of the Interior, the study relied on data gathered by field biologists stationed on 13 platforms across the Gulf.

Ornithologist John Arvin, from the Gulf Coast Bird Observatory, was one of those researchers. He lived on a platform eight miles offshore for three months during the spring migration of 1998. “When you were out there you’d see nothing but steel and water,” he says—that is, until the birds arrived.

One day Arvin saw a migration he describes as “the most amazing ornithological experience I have ever had”: a seemingly infinite flock of songbirds, kingfishers, herons, and shorebirds. He also spotted smaller throngs over the course of the season. Whenever the birds ran into stormy weather and high winds, Arvin noticed that some of them—usually the weaker ones, he speculates—would take refuge on the rig. “The platforms are out there and they do provide a landing site if the birds are in serious need of one,” he says.

This behavior was observed at several rigs over the course of the study, leading the authors to conclude that migrating birds sometimes use the platforms like “stepping stones” during their exhausting flights across the Gulf. The researchers also concluded that the structures act as refueling points. “You would think that a platform out in the ocean would be pretty sterile, and it is to a large extent. But there are insects out there,” Arvin says. The researchers often observed birds foraging and occasionally drinking the condensation on rig pipes. “They use [the rigs] when they’re desperate, and they ignore them the rest of the time,” Arvin says. “That was my experience, at least.”

Out of sight

Unfortunately, even as the complicated connection between the gas and oil rigs and migrating birds draws more interest and scrutiny, the scientists themselves are being allowed less access to the rigs than they once were.

“We were essentially the first non-petroleum people that were allowed on those platforms,” says Arvin. They were also some of the last. The age of “piggybacking on somebody else’s infrastructure to do research” has passed, says Andrew Farnsworth, an ornithologist from the Cornell Lab of Ornithology who contributed to the 2005 study. “I also think there’s some trepidation from the energy industry, because, rightfully so or not, they are often vilified. If some rig is a major source of mortality for birds, that’s going to be bad news [for the industry].” Of course, this makes it tougher for researchers to contribute fresh data on how many birds the Gulf’s rigs are actually killing. “Without that big pile of dead birds, it’s hard to get public support,” says William Evans, director of Old Bird, a nonprofit group that uses acoustic monitoring to track migrants in North America.

Even if it’s hard to come by additional data, there are plenty of theories about how these structures could affect migrants in the Gulf. If the negative impacts are proven, they could outweigh any benefits the platforms might offer. One theory is that the platforms could actually harm the health of species. “There’s a range of fitness in the birds that take off. Some of them are not fit enough to withstand a Gulf crossing,” says Arvin, in which case they take refuge on a rig. “There is a school of thought that by allowing the birds to survive, you’re actually undermining the genetic makeup of the species,” he says. Currently, it’s no more than an idea, with little scientific backing, he says. But it does raise questions about possible long-term effects on populations.

The researchers from the 2005 study also discovered that rigs make perched migrants especially vulnerable to predators. “Peregrine falcons learned that these platforms were good places to find birds,” Farnsworth says. The study estimated that the raptors—drawn by the rich pickings—were present on most major rigs across the Gulf during fall migration.

After dark

Then there’s the question of what happens when the sun goes down. Evidence shows that a well-lit platform can disorient migrants, and occasionally kill thousands of birds in one go. “The reason that happens, we believe, is that the birds have an attraction to light,” says Robert Ronconi, a biologist from Nova Scotia’s Acadia University, who led a prominent review of the literature on birds versus offshore platforms.

At night, oil and gas platforms—active or inactive—are lit up like Christmas trees, warning boats and low-flying aircraft to stay away. But for birds, the lights can have the opposite effect. In bad weather, when they can’t use their usual visual cues, migrants have been known to make a beeline for the lights. Sometimes they’ll circle the structures for hours instead of continuing on with their journeys, Ronconi says. It can be a fatal diversion, depleting the reserves the birds need to complete their Gulf crossings.

While he was stationed on the rig, Arvin recalls, he would occasionally gather dead birds from the deck. “I'd say about half the birds I salvaged were from strikes, slamming into the sides of the platform.” Although he found only 34 dead birds during his three months at sea, the researchers from the study estimated that, on average, each of the 4,000 platforms present in the Gulf at the time would result in 50 birds deaths per year. That led to a much more alarming estimate of 200,000 birds killed annually.

Even if researchers no longer have access to the rigs, there is more data coming in, sometimes from unexpected places. For instance, Marcus Drymon, a scientist from the University of South Alabama who studies the diets of sharks in the Gulf of Mexico, discovered that “backyard birds” like flycatchers, wrens, woodpeckers, and doves were showing up in tiger shark stomachs. He’s now launched a crowd-funded effort to investigate the potential link between oil platforms, bird collisions, and the sharks’ good fortune. If proven, the connection could show that current estimates for rig mortality rates are too low.

Others see gas flares, which are used to burn of excess gas, as a real culprit. Just like lights, these sudden bursts of flame are enticing to birds; on rare occasions, they can kill thousands at once. Two years ago 7,500 songbirds were incinerated when they flew directly into a flare at a New Brunswick gas plant. For the most part, the effects of flares on birds have gone unstudied, on both land and sea.

The 2005 study attributed 46 percent of the tallied bird deaths to starvation. “If they get tired and they land on the rig, and then there’s no food the next day, do they then have enough strength to get off?” Old Bird’s Evans wonders. After studying the impacts of different types of lights on birds, he believes that rigs are a giant hazard for migratory species in the Gulf. He offers a straightforward and relatively inexpensive partial solution: facing rig lights downward to make them less visible to birds flying above.

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Clearly oil and gas drilling in the Gulf is going to continue, and any solution to its effects on migrating birds is going to require the help of the industry. The first thing the oil and gas companies should do is give scientists access to the rigs so they can gather more data. The researchers have plenty of ideas: cameras and sensors on platforms to monitor visiting avians, frequent reports on bird kills, and, overall, making rigs cleaner and freer of oil. But the entire approach has got to change. And turning these massive, sometimes unused towers into tools for research would be a good place to start.

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