How Oil Spills Affect Birds

How Oil Spills Affect Birds?

We’ve all seen the shocking images of large tankers spewing millions of gallons of oil into our seas and we are all aware of the devastation these disasters cause to wildlife. But the impact on birds is often less reported on or at least in terms of harm it causes. Just a tiny ¾ of an inch (18mm) drop of oil can be enough to cause harm to birds.

What Are The Causes Of Oil Pollution?

There are many large scale oil disasters that make headline news like illegal dumping, offshore drilling and oil tanker leaks. But small oil pollution can be just as bad for birds and other wildlife. Oil spills caused by:

  • Leaking Motor boats
  • Damaged Jet Skis
  • Illegally Dumped Engine Oil
  • Road Pollution Run Off

The majority of these small spills go unreported due to their small size and small area covered. But any birds that come into contact with it will in all probability die.

Which Types Of Birds Are Most Affected By Oil Pollution? 

The birds that are most affected by oil pollution are seabirds mainly birds like:

  • Terns
  • Gulls
  • Ducks
  • Auks
  • Puffins
  • Pelicans
  • Loons
  • Penguins
  • Grebes

Once the oil reaches the shoreline there are a more bird species likely to be effected, that includes:

  • Godwits
  • Sandpipers
  • Curlews
  • Dunlins
  • Green Shank
  •  Phalaropes
  • Snipes
  • Little Stints
  • RedShank
  • Ruff
  • Sanderling
  • Turnstones
  • Whimbrels
  • Woodcocks 
  • And Many More

Not forgetting birds of prey like Sea Eagles, Golden Eagles and Ospreys. All can be affected by sea bound oil pollution. So in essence no bird is safe from the effects of oil pollution. 

How Does Oil Affect Birds?

The obvious effect is how oil coats a bird’s plumage with that thick, sticky, slimy, grease. Bird’s feathers are designed in a way that they work perfectly by releasing a small amount of oil during preening. They have a delicate way of interlocking with each other to provide warmth, insulation against heat and cold, waterproofing and the ability to fly. Once a bird is coated in oil, it will also start to sink as it loses it’s natural buoyancy.

If the bird is fortunate enough to be on shore, the oil covered birds will try to preen, as it is impossible to remove such thick oil based sludge, they preen all the more. This causes them to swallow much of this poisonous slime. This sadly leads to a slow death due to toxicity of the lungs, liver, kidneys,intestines and other major organs. If by some miracle they don’t die their constant preening, which is them trying to realign their feathers and clean up, will cause them to exert more energy than they can afford to lose. So many birds with only slight coverings will die from exhaustion, lack of food and dehydration.

Other Problems Caused By Oil Pollution

As if getting covered in oil and watching other members of your flock die from lack of food and water wasn’t enough. Large areas of sea can be covered in the oil slick. This leads to the birds who are already exhausted and malnourished, having to fly farther afield to find food. If this happens during the nesting season, any oil that’s transferred from the parent to the eggs can cause suffocation of the unborn chick. If it’s earlier in the season and the females have yet to lay the eggs, any oil she has ingested will cause thinning of the egg shells. This can lead to the eggs getting crushed as the parents try to incubate them, or even if they do hatch, chicks who’s parents are subject to oil pollution often feed the chicks polluted food which will lead to deformities at best and death as the ultimate result.

Oil In The Ecosystem

Even a very small amount of oil can lead to knock on effects, plant life can be affected, with less plants underwater, fish and other small sea creatures have to find new sources of food and shelter. As they move away from their original locale, the seabirds that relied on that particular ecosystem to survive, have to expend more energy to find sources of food. This extra flying time leads to exhaustion and once a bird is exhausted it is close to death. Exhausted birds, much like exhausted people suffer from confusion and in many cases birds lose their sense of direction because they are too tired to think straight. Seabirds eat on average 20% of their body weight daily, so it doesn’t take long for them to deteriorate.

Any fish they do catch are probably already affected by the oil, so the birds are adding poison to their already overstressed internal organs. It sounds like we are painting a bad picture here, that’s because it is a bad picture. In fact it’s actually worse than we can describe it.

What Are The Damages Caused By Oil Pollution On The Ocean?

It’s not just the birds, that get affected by oil pollution, it is also:

  • Plant Life
  • Fish
  • Insects
  • Molluscs
  • And Other Marine Life

The environmental damage from just a minor oil slick can be catastrophic. On a world level we will have to face the consequences of this in years to come. But sadly for the birds, many will die immediately, and quite frankly, they’re the fortunate ones. The birds that make it to the shore very often die a slow agonizing death due to organ failure.

How Do Any Oiled Birds Survive?

With the help of dedicated teams of mainly volunteers working under a team of vets, many birds are nursed back to health. What is needed are the facilities to stabilize the birds, feed them and when they are ready, clean and degrease them under the supervision of experts.

Birds Exposed To Light Oil Contamination Fly Off Course

In recent tests conducted by US biologists and published in the journal Environmental Pollution,homing pigeons were used to discover what happens if birds get caught up in an oil spill. They found that pigeons that had been slightly covered in oil veered off course and returned home much later than expected. Plus they took a much longer time to recover, than a control group with no oil on their feathers.

This was the first such test on the effects of light crude oil coverings on long distance birds and they found that even at low levels of contamination, it could probably cause serious impacts on migrating birds. Lead scientist Dr. Cristina Perez said:

 “We expected that the birds would have difficulties with flight and be slower in their arrival, but we did not expect such an obvious flight path difference.” 

The study applied crude oil to the wing and tail feathers on some of the homing birds using a paint brush. The oil was collected from the Deepwater Horizon oil spill and applied in the same fashion as seen in birds affected by the spill.

The homing pigeons were repeatedly trained to carry out the 161km (100 miles) flights from release points and their loft at home. All were wearing GPS recording devices and after release, they nearly all took longer flight courses in both time and distance compared to the control group (with no oil applied).

Dangerous Journey

The longer routes (which were over double the flights of the unoiled birds) consisted of flying around lakes, and utilising mountain upwinds. They obviously chose to detour from lakes which could cause potential danger for them. They were possibly using their local knowledge to make the trip easier.

These options would not be available to migrating water birds that became covered during their first migration. Especially young migrating birds, who would have absolutely no knowledge of large areas of water or other environmental hurdles.

The oiled birds were underweight compared to the control group and also compared to their pre-oiling weights. Which would suggest they either didn’t know where to stop to refuel, or they had trouble eating any food they did find. The coated birds also had difficulties taking off and put off taking off even when the control group left right in front of them.

Earlier Studies

All earlier studies have always focused on heavily coated seabirds, but as Professor Chris Pritsos pointed out the discoveries made by his team were important. They can now see how even lightly soiled birds can be affected. He also said that these effects could cause serious problems for any migrant birds who were caught up even slightly in the oil spill. Dr. Perez pointed out that a series of GPS recorders and uncontaminated pigeons “Could be considered for testing the effects of other environmental contaminants”  for the kind of impact that “wouldn’t be discovered in birds in a wind tunnel environment alone”. 

The Difference Between Land Birds And Water Birds


Another expert on pollution impact on seabirds Dr Kees Camphuysen from the Royal Netherlands Institute of Sea Research who never took part in the study said that it was “interesting that slightly oiled birds with only one task were hindered and that the effect lasted fairly long”. He also said that water birds would probably be affected worse than the pigeons because their cleaning efforts would be hampered by being at sea. 

The Deepwater Horizon Disaster

The Deepwater Horizon was an offshore drilling rig that managed in September 2009 to drill the deepest oil well in history. Reaching a vertical depth of 35,050 feet (10,683m).The spillage consisting of 134 million gallons of crude oil into the Gulf of Mexico occurred on the 20th of April 2010. It was responsible for the death of 11 men and the fireball from the explosion was visible from 40 miles (64 km) away. On the 22nd of April 2010 the rig sank, which resulted in the crude oil spilling into the sea, and polluting the seabed. The spillage continued until the 15th of July when it was finally closed by a cap.The disaster happened approximately 41 miles (66km) off the Southeast coast of Louisiana, and is the largest marine oil spill in history. 

The Effects On Land Birds From An Oil Spillage At Sea

In the marshland along the coast of the Gulf Of Mexico, live seaside sparrows. They don’t grow any larger than around 5 inches (12.7 cm) and live their entire life in the grassy marshland. They never go anywhere near to the sea, and yet they too have been affected by the Deepwater Horizon disaster. A team from Louisiana State University is finding out how.

Marshland Grasses Killed By Oil

From the start of the spill in April 2010 until the well was capped in July 2010, over 1,000 miles (1,700 km) of the coastal shoreline was contaminated. With nearly ½ of that being Louisiana marshland. Nearly 30 foot (9 m) from the shoreline, practically all of the marsh grass was destroyed by the oil. The oil completely blocks the sunlight resulting in the death of the grasses.

Effects Of Hurricane Isaac

With the grasses dead and gone, and no roots to hold the soil, the land was eroded by storms. Most of the remaining oil became buried under the sediment, which being virtually oxygen free, there are hardly any microbes to break down the oil. It stays buried until severe storms like Hurricane Isaac bring it back to the surface. The Louisiana University team are trying to find out if the resurfaced oil will harm wildlife.

How Are The Sparrows Faring?

The team searches the marshland for the sparrows nests and checks the eggs and chicks. 2 to 3 years after the oil spill the sparrows that had nests in the marsh that had been covered with oil previously, only raised 5% of their young. Compared to those who made their nests in unoiled marshland who reared over 50% of their young.

There are a few reasons for the poor survival rates these include:

  • Remnants Of Toxins From The Oil
  • Contaminated Insects From The Oily Mud
  • Less Foods Available Due To Insect Migration To Unpolluted Land

Adult Sparrows

The researchers are also concerned with how the pollution affects the adult bird population. The toxicity from the oil pollution can cause: 

  • Cancer
  • Liver Disease
  • Suppressed Immune System
  • Reproduction Difficulties
  • Behavioral Problems

The researchers are looking for a gene called CYP1A which metabolises the poisons in the oil. They are also searching for stress hormones in the adult sparrow’s blood caused by detoxifying their food from oil, then that could cause stress related mating issues, which would account for the lack of new chicks. The long-term fears are that if the seaside sparrow population declines too far, as they are the top predator on the marshland, they currently keep the snail and insect population in check, which can create an imbalance which  will cause a reduction in the biodiversity of the marshland. 

How Can The General Public Help During These Situations?

As we can see from the previous paragraphs, it can take many years to clean up polluted areas. But there are ways in which we can help. They include:

  • Donating to charitable organisations that are helping with the clean up.
  • Volunteering with the clean up teams on site.
  • Taking part in campaigns to raise awareness of these types of disasters.
  • Reporting any oil spillages or pollutants to the relevant authorities if you spot them.
  • Making sure to keep your own water craft up to speed with regular services to prevent any leakage.

As we have seen, oil can be deadly to wildlife and especially birds. We all need to do our bit to keep our waterways, rivers and seas free from oil and other contaminants for the sake of all wildlife.

Frequently Asked Questions

What types of birds are affected by oil spills?

The types of birds affected by oil spills are mainly seabirds. In the UK that includes ducks, gulls, terns, grebes, puffins, sea eagles, and any other seabirds. But also birds that live along the shore line like snipes, sandpipers, woodcocks, curlews and many more.

How many birds die from oil spills?

Every year more than 500,000 birds die from oil spills worldwide.

Do oil spills kill fish?

Oil spills kill fish and destroys their environment and kills their food too.

How many oil spills happened in 2020?

There were 3 oil tanker spills in 2020.