Oil spills can have devastating effects on seabirds. When oil is spilled into the ocean, it forms a thin slick across the surface of the water. Seabirds that come into contact with this oil can suffer from a range of detrimental effects. Oil damages birds’ feathers, which are essential for maintaining body temperature and buoyancy. It can also be ingested when birds try to clean themselves, leading to severe internal problems. Many seabirds lose their waterproofing and buoyancy after coming into contact with oil and die from drowning, starvation, or loss of body heat.
How do oil spills affect birds?
Oil spills affect birds in a number of ways:
– Feather damage – Oil breaks down the structure of feathers, causing them to separate and lose their waterproofing abilities. This makes the birds more vulnerable to hypothermia.
– Ingestion – Birds may ingest oil while preening their feathers. This can cause internal injuries and organ damage.
– Drowning – Birds may lose buoyancy and the ability to fly after oil damages their feathers. Heavily oiled birds may drown.
– Starvation – The effects of oil may make it difficult for birds to forage and catch prey. Birds may starve if oil spill cleanup takes away food resources.
– Nest abandonment – Birds may abandon their nests and eggs if oiled, leading to reproductive failure.
– Respiratory problems – Birds can suffer lung, air sac, and tracheal damage if they inhale fumes from spilled oil.
What species are most affected?
Species that are most impacted by oil spills include:
– Seabirds – Examples: puffins, murres, guillemots, shearwaters, fulmars, gulls, terns, skuas, petrels. These species spend most of their lives at sea, floating on the surface of the water. Thus, they are likely to come into direct contact with spilled oil. Their feathers become coated, causing hypothermia, drowning, and starvation.
Species | Reasons affected |
---|---|
Puffins | Spend most of lives floating on sea surface. Reliant on feathers for insulation and buoyancy. |
Murres | Dive from surface to catch fish. Oiled feathers lead to hypothermia and drowning. |
Fulmars | Surface feeders whose populations declined after Exxon Valdez spill. |
– Shorebirds – Examples: sandpipers, plovers, oystercatchers. These birds forage on intertidal areas that often get coated in oil during a spill. Exposure when feeding can coat their feathers.
– Waterfowl – Examples: ducks, geese, swans. These birds float on the surface of wetlands and estuaries, areas that commonly see oil slicks during spills. Contact with spilled oil can lead to ingestion and feather damage.
– Wading birds – Examples: herons, egrets, ibises. These species feed in marshes and along shorelines. Their feathers may become oiled when searching for food in spill zones.
Sea Ducks
Sea ducks such as scoters, eiders, and long-tailed ducks are especially vulnerable as they spend winters gathered in large flocks floating in bays and estuaries. Spilled oil can coat and kill hundreds or thousands at once.
What are the long-term impacts?
Oil spills can have many long-term impacts on birds, including:
– Chronic mortality – Weakened birds may continue dying in the months and years after a spill.
– Reduced reproduction – Birds that later breed after being oiled may produce fewer chicks. Oil can impact their health and breeding behavior.
– Population declines – Spills may severely reduce regional populations by killing thousands of birds. Recovery can take decades. Murres have still not returned to pre-Exxon Valdez spill numbers in parts of Alaska, for example.
– Habitat loss – Oil can persist in shoreline and marsh sediments. This can degrade or eliminate food resources and nesting habitat.
– Food web impacts – The loss of many seabirds can impact wider ecosystems. Their role as predators and prey in marine food chains is disrupted.
– Behavioral effects – Oil exposure may hinder birds’ migration, breeding displays, parenting, and foraging. This can reduce long-term fitness.
Exxon Valdez Spill Impacts
The Exxon Valdez spill in 1989 killed an estimated 200,000 seabirds. Still, over 30,000 carcasses were recovered. Certain species like pigeon guillemots and marbled murrelets suffered population declines that they have yet to recover from in oiled areas.
How are birds rehabilitated after oil spills?
Rehabilitating oiled birds is a complex, lengthy process. The key steps are:
– Capturing and stabilizing – Birds are carefully collected from spill zones and taken to rehabilitation centers. They are warmed, given fluids, and assessed.
– Cleaning – Oil is carefully removed from feathers using cleaning agents. This process can take days for heavily oiled birds. Feathers may be plucked if severely matted.
– Rinsing – Cleaners are rinsed off fully until water runs clear. This ensures no residue is left on feathers.
– Drying – Cleaned birds are thoroughly dried in kennels before waterproofing is restored. Preen glands help re-establish natural oils.
– Waterproof testing – Birds are tested in tanks of water to ensure their waterproofing was restored during cleaning. They must pass before release.
– Conditioning – Birds are caged with pools for swimming to rebuild flight muscles and feather coordination.
– Release – Once fully rehabilitated, birds are released back into the wild at appropriate spill-free sites.
Rehabilitation Success Rates
On average, only around 10-15% of oiled seabirds survive the rehabilitation process. Heavily oiled birds have much lower survival odds. Care must be taken upon release to prevent predation of weakened birds.
How are oil spills cleaned up?
Key techniques for cleaning up oil spills include:
– Booms – Floating barriers are placed around spills to contain the oil and prevent spreading.
– Skimmers – Boats use skimming equipment to mechanically recover oil from the surface of the water.
– Sorbents – Materials like straw and plastics are spread to absorb and soak up oil.
– Vacuums – Industrial vacuums may be used to suck up oil from shorelines and the water’s surface.
– Burning – In some cases, contained surface oil may be deliberately burned off. This must be done carefully to minimize air pollution.
– Dispersants – Chemical agents can be sprayed to help break up oil slicks into smaller droplets that disperse naturally. Their toxicity to wildlife must be considered.
– Bioremediation – Nutrient or microbe addition can help accelerate the breakdown of oil naturally by microorganisms.
Cleanup Considerations
Spill cleanup can further harm birds if conducted without care, by disturbing their habitat or forcing oiled birds to flee before they can be rescued. The impact on birds must be considered when selecting cleanup methods.
How can oil spills be prevented?
Some ways to help prevent oil spills include:
– Phasing out offshore oil drilling and pipeline networks that traverse bird habitat. This eliminates spill sources.
– Improved tanker safety and staff training to avert accidents at sea and in port. Double hull requirements help minimize spill volumes when accidents do occur.
– Better maintenance and quality control for existing drilling, pipeline, and port operations. Regular inspections and equipment updates reduce risk.
– Advancing spill response methods to contain and clean up spills more quickly when they do occur, before damage spreads. On site response teams and equipment can react immediately.
– Stricter regulation and oversight of drilling permits and oil transportation. Fines for safety violations incentivize spill prevention.
– Transitioning global economy away from oil and toward renewable energy. This reduces long-term demand for offshore drilling in delicate ecosystems.
Prevention Challenges
However, the oil industry remains powerful and many nations are still highly dependent on oil. This makes prevention an ongoing challenge. Existing infrastructure near bird habitat leads to ongoing smaller spills.
Are oil spills a major threat to seabird populations?
Yes, oil spills are one of the most significant threats to seabird populations worldwide:
– Spills are an acute threat that can kill hundreds of thousands of birds in short periods. Species with restricted ranges are most vulnerable to massive die offs from spills in their habitat.
– Chronic smaller spills from boats, pipelines, rigs, and port operations produce lower-level but ongoing mortality.
– Even small amounts of oil from spills and bilge dumping can foul feathers enough to prove fatal. Birds do not need to be coated in visible oil to suffer lethal effects.
– Spills compound other threats like overfishing, habitat loss, climate change, and pollution that seabirds already face. Their combined effects are greater than any one threat.
– Many seabird species are long-lived and slow to reach maturity and reproduce. Large die offs from spills cannot easily be reversed.
– Breeding colonies on remote islands and coasts are highly susceptible to spills at sea or on shorelines. Spills can wipe out a disproportionate segment of total population.
Conclusion
Oil spills present an immediate and chronic threat to seabird survival worldwide. Minimizing this threat through spill prevention and improved response must remain priorities for the conservation of seabirds, many species of which were already experiencing population declines before considering oil spill impacts. We must continue working to reduce reliance on oil and shipping in seabird habitats, or risk losing these iconic species.