The environmental group GOB and Balearic ornithologists check the movements of sea birds every fortnight, and they will be on the watch for the arrival of birds affected by the black tide in Galicia. They are particularly worried about the Manx Shearwater, which, after breeding in the Balearics in March, moves to the Atlantic and Cantabrian coasts in June, remaining there until September and October, when they return to the islands. Toni Muñoz of the GOB says that most of these birds are probably here or were on the way when the black tide hit Galicia. Even so, it will be very difficult to say how many brids have been affected by the Prestige catastrophe. He went on to say that according to a 1991 survey, there were between 3'300 and 5'000 pairs of Manx Shearwater in the Balearics but we cannot be more precise at the moment. The Manx Shearwater (Puffinus puffinus) is endemic to the Balearics. It only comes to breed in the archipelago and is always on the coast or at sea. It comes and goes from the Atlantic via the Mediterranean, Gibraltar and Portugal. It lives in caves and on cliffs and colonies can be found in the Balearics in La Trapa, Dragonera and Cabrera and, particularly, in Formentera. Muñoz said that Manx Shearwaters had been spotted in Formentera in early November, having returned from the Atlantic, but so far none had been found with oil stains. It is to be supposed that they returned before the accident, Muñoz said. He added that if birds were found with oil stains it was not a cause for concern, as if they have been able to arrive then they will survive. He added that the birds shed their plumage in autumn, anyway, and this will get rid of any stains. Muñoz explained that most of the birds affected would die before they could return, because they try to clean their feathers and swallow oil in the process. The Balearic environment ministry has put the bird recovery centres of the islands at the disposal of the Xunta (regional government) of Galicia, to help in the recovery of animals affected by the oil spill. The ministry will launch a series of lectures on biodiversity, with an exhibition on the birds of the Balearics by Joan Mayol tomorrow.