Scientists were scratching their heads yesterday over the mass death of hundreds of waterfowl in northern Lake Koroneia, one of Greece’s most endangered bird habitats. Local hunters have found at least 500 dead birds in the lake, some 20 kilometers (12 miles) east of Thessaloniki, and fear there may be more corpses in the area. The dead birds include 53 rare Dalmatian Pelicans, as well as shovelers, black-winged stilts and several gull species. Thessaloniki University scientists who have seen the corpses said there were no initial signs of disease, and now propose to conduct tests to see if they were poisoned. But local fisheries experts who have taken water samples say there is no indication of pollution. The EU Commission is taking Greece to court for its failure to protect the lake, which has been heavily polluted in the past and whose waters have almost disappeared.