Oil victims

It is a pitiful sight: seabirds covered in oil. These birds are no longer able to dive or float because the oil produces leaks in their plumage. The oil causes their feathers to stick together permitting water to penetrate to their skin. Usually, oil victims become undercooled. Only a few oil slicks originate from a stranded tanker. The oil is more often consciously dumped. Oil victims are cared for at bird rehabilitation centers.

The percentage of birds besmeared in oil on the Dutch coast in the winters of 1986-1995 has decreased in comparison to the period 1969-1985. Apparently, the amount of oil at sea has also notably declined, partially due to the MARPOL treaty. The number of Dutch 'oil birds' compared to the other countries surrounding the North Sea is still high. For example, the European goal is that less than 10% of the total number of birds washed ashore are guillemots (oil victims), but the Beached Bird Survey performed by Kees Camphuysen has found that 50% of the dead birds are oil-guillemots.

Contact with the oil: catch a cold or drown

When a bird comes in contact with oil, it does not mean imminent death. However, the bird's plumage is no longer waterproof. The animal loses its warmth insulation and catches a cold. Its floating ability also diminishes; the bird can even drown. In addition, it is known that brooding eggs from a bird besmeared in oil have fewer chances of hatching. The kind of oil, the time of year and the place of the oil contamination determine the extent of the damage. Heavy ('thick') oil floats longer on the water surface than light oil, which evaporates more quickly or mixes more naturally in the water column. A heavy oil spill can therefore cause more damage to birds and other sea life. Most of the oil victims along the North Sea coasts are found in the winter.

The lower temperature, regular storms and little availability of food in the winter months already present hardships for the birds. More and more birds lightly covered in oil and totally emaciated have been washing ashore, especially in recent years. Oil is probably not the direct cause of death in these cases.

From sheer necessity, the winter with its often stormy wind and short days is the time of year in which there is the least control on illegal oil discharges by skippers. Every skipper that discharges oil on the North Sea knows that he probably will not be caught since proof is impossible to find when the control can only be continued after the storm abates.

Where the oil pollution occurs is also important. A small oil slick in an area rich in birds can cause many more victims than a large slick elsewhere. Between 1975 and 1985, the number of oil victims among the kittiwake, auk and guillemot increased remarkably. This was probably due to a change in the winter distribution of these species. They now spend the winter in the heavily polluted southern North Sea. Divers, grebes, gannets and common scoters are also regularly among the oil victims that wash ashore.

Seabird species that are often on the water surface are the most vulnerable. They can swim into an oil slick or end up in one after a deep dive. The guillemot is extremely sensitive for oil pollution. The animals are permanently at sea, with the exception of a short period in the summer when they brood their eggs on the steep cliffs. Guillemots spend most of the time swimming around and because they spend the winter in the heavily navigated North Sea, large numbers come in contact with oil annually. Guillemots and auks run an extra risk after brooding. The parent birds molt in that period, all flight feathers at one time, and are unable to fly. The chicks jump into the water before they are able to fly. Parents and juveniles can swim hundreds of kilometers over the sea before being able to fly (again). Escaping an approaching oil slick is impossible.

Bird rehabilitation

washing a guillemot in a bird washing machine

Every year, tens of thousands of oil victims wash up on the shore. This is usually only a small fraction of the total number of birds affected by oil; most of them never wash ashore. Those that are still alive can be brought to special bird rehabilitation centers, which have facilities and guidelines for caring for the oil birds. Ecomare is one such bird center and receives approximately 500 birds every year, especially during the wintertime. Other larger bird sanctuaries are in Middelburg, Rotterdam, Haarlem and Anjum.

If possible, these birds are washed with a special detergent. Afterwards, they must regain their strength and wait for their plumage to become water-tight again. After an average of two months, they can be released in the North Sea. Caring for birds is like mopping with the oil tap open. Of course, it is much more important to stop the oil pollution.

Study of oil victims in the Netherlands

The former Directorate General Shipping and Maritime Affairs (DSGM, now DGG: Directorate General for Transport of Merchandise) from the Ministry of Transportation and Public Works wished to know to what extent was monitoring oil victims a useful expedient for measuring the effectiveness of the Environmental Policy Plan to decrease the oil discharges at sea by ships. The counts that were used before this study began in 1985. The study was performed by the Netherlands Seabird Group, under the title "Beached bird survey".

The percentage of birds smeared in oil found along the Dutch coast in the winters of 1986-1998 had decreased among all the species compared to the period 1969-1985. This decrease is considered to be a sign that the risk of coming in contact with oil has declined for these animals. Kees Camphuysen carried out the project "Beached bird Survey" for the Dutch Seabird Working Group, a study commissioned by the Ministry of Public Works. According to him, the number of 'oiled birds' found is still high when compared to the surrounding North Sea countries.

Almost three fourths of the recognized oil contamination appeared to be discharges of oil mixtures. Raw oil from tankers or oil platforms is rarely found along the Dutch coast.

There was a decrease found in all of the studied species and groups of coastal birds and seabirds. Assuming that the habits of the birds has not essentially changed and that their distribution at sea has also remained more or less the same, the Seabird Group concluded that the amount of oil at sea is the determining factor for the chance of coming into contact with oil.

The researchers make a distinction between three groups of birds. One group consists of birds which inhabit the coastal waters: divers, grebes and scoters. The second group consists of waterfowl, grallatorial birds and Larus gulls, and the third group contains the real seabirds: the fulmar, the kittiwake, the auk and the guillemot. When the percentage of oil pollution is seen as the chance that a bird ends up dead or alive in the oil, and if this chance is determined by the amount of oil at sea (number of slicks, surface oil of tons of discharged oil), then the decline in the oil pollution percentage is directly parallel to the decline in oil pollution. With the proposed assumptions, it can be concluded that the oil pollution has decreased by at least 20% since 1986, according to the bird researchers.

It has now been proposed to make a more direct connection between the information concerning birds stranding, shipping accidents and the prevention of oil slicks. In the near future, it should also be attuned to an international relationship so that the counting results from all of the North Sea countries can be directly and regularly compared. It will then be possible to keep a constant watch on the situation in the various sections of the North Sea.

Weblinks

Site with data on Dutch Victims of Oil Studies (NSO) (Ducth):
http://home.planet.nl/~camphuys/NZGNSO.html

LIst of guidelines:
http://www.ipieca.org/publications/publications_search.php?crit=oilspill&select=yes

Source: de Vleet, Ecomare