The major eruption of the volcano under the Eyjafjallajokull glacier yesterday has not only grounded UK aircraft but has caused concern for the welfare of migrating whooper swans. Dr Olafur Einarsson confirms that that there is dense ash and total darkness to the southeast of the volcano, near the area dubbed “Whooper Airport” by Prof Colin Pennycuick when we first tracked whooper swans to Iceland in the mid 1990s. However, despite this being a major landfall area for the birds, most of the swans have already reached Iceland, and the stragglers should see the ash/larva cloud quite clearly as they approach the Icelandic coast. Oli says that visibility on the coast is OK, so they should be able to track east or west (depending on their final destination) without entering the black-out conditions. The first Eyjafjallajokull eruption (just before Easter) was on a much smaller scale and apparently not such a threat to humans or migrating birds arriving in the country.

Oli reports that bird deaths have occurred during previous eruptions of other volcanoes in Iceland, when the feeding areas were covered with ash, causing major problems for farmers and birds. Fortunately internationally important whooper swan staging or breeding sites are currently still suitable for swans as the main area affected, between Vik (in the west) and Kirkjubaejarklaustur (in the east), is primarily an area of sand and gravel. The swans’ main spring staging areas are at Lon (further east) and Thykkvibaer (to the west) and these sites are thought to be OK. However, the previous major Eyjafjallajokull eruption (back in 1820) continued for 2 years, and the wind may blow the fall-out in different directions if the current eruption continues. Moreover, Oli mentioned that there is a historic pattern of nearby Katla erupting shortly after Eyjafjallajokull eruptions. So we must keep an eye on both of these possibilities. The last major eruption for Katla was in 1918, but it has been showing signs of unrest since 1999.