An area may be frequented by migratory birds.Logical formLearned from2 sentences. A virus may be brought by migratory birds.Logical formLearned from2 sentences. Migratory birds may fly to a continent.Logical formLearned from2 sentences. Persons may kill migratory birds.Logical formLearned from2 sentences. Migratory birds may undergo tests.Logical formLearned from2 sentences. Migratory birds may spread a virus to a country.Logical formLearned from2 sentences. (Bird sanctuaries) may draw migratory birds from parts of the world.Logical formLearned from2 sentences. Contact can be with migratory birds.Logical formLearned from2 sentences. Migratory birds may carry a strain of a virus.Logical formLearned from2 sentences. Some migratory birds may pass through a country.Logical formLearned from2 sentences. Some migratory birds may die in a sanctuary.Logical formLearned from2 sentences. Migratory birds may be suspected of bringing (bird flu).Logical formLearned from2 sentences. A lake may be used by migratory birds.Logical formLearned from2 sentences. Officials may monitor migratory birds.Logical formLearned from2 sentences. Migratory birds may fly from a continent.Logical formLearned from2 sentences.