The spring migration of African birds northward through Europe calls for systematic tests on samples if avian flu is to be warded off, experts said yesterday just as fears had abated with the culmination of a winter migration cycle which brought thousands of wild birds into Greece. Inspections must begin immediately as birds have already started migrating from Egypt, said the head of the Agricultural Ministry’s bird flu unit. «Samples must be taken from many migratory birds over a long period of time,» Panayiotis Triantafyllou told Kathimerini. However, the head of the Thessaloniki branch of the Hellenic Ornithological Society, Yiannis Tsougrakis, was more reassuring. «Many birds will come from Africa, but not of the species that have shown susceptibility to bird flu until now,» Tsougrakis said. Yesterday the H5 strain of the virus was detected in two more wild birds, samples of which were sent to Britain for further analysis. So far, 26 birds found in Greece have tested positive for the fatal H5N1 strain.