Oil Spills and Seabirds
We’ve all seen those awful pictures of seabirds covered in black oil when then has been an oil spill in the ocean. The fact that these birds are in serious trouble is always obvious and it is hard to miss a giant oil slick making its way across the water. But what about small amounts of oil? Do minor spills also impact birds? It is a question that scientists have been pondering for a long time. Following a recent study, they now have the answer.
There are constantly small oil spills into the oceans around the world. Researchers from the University of Western Ontario in London, Canada set out to discover if these small amounts of oil could harm seabirds. Their findings have proved highly significant as they show that minor oil spills can cause big trouble. These spills may not hit the headlines but they are quietly doing a whole lot of damage.
The researchers used western sandpipers, a species which was serious affected by the 2010 Deepwater Horizon spill. The team trained 24 western sandpipers to fly inside a wind tunnel for 2 hours at a time. They then used a small paintbrush to apply oil to the wingtips and tails of some of the birds and flew them alongside birds which were oil-free. Using a resonance scanner, they measured the proportion of fat in each bird before and after flight. Following the flights, the oiled birds were found to have consumed 22% more energy than the clean birds.
Further experiments were conducted apply oil to different areas of the birds’ bodies. The more oil that was applied, the more energy the birds used. Indeed, energy usage increased at a faster rate than the quantity of oil applied. Half of the birds with oil on the wings, tails and bodies attempted to land and could not complete the flight test. The oiled birds were flapping their wings more frequently and were experience drag and so were tiring quickly.
Oil and Migration
If wild birds use more energy they need more time to recover from flights. This will impact their migration. When migrating from the Gulf of Mexico to Alaska, for instance, an oiled western sandpiper could be delayed up to 45 days. As the birds are on a tight schedule regarding establishing nests, oiled birds may not be able to breed because they simply arrive too late. The western sandpiper must perform their breeding rituals, lay their eggs, raise their young and leave before snow arrives in September.
Seabirds in Decline
The research demonstrates that even a small amount of oil could devastate seabird populations. Small spills often go unreported so it is hard to know what the true impact of these events is. Many seabird populations have been in decline in recent years. There are a variety of reasons for this, but it looks certain that one of them is oil.
More research will be required to determine the number of birds which are being affected by oil spills. In addition to interfering with their power of flight, oil can also be accidentally ingested and poison the birds. Oil is very bad news!