A past can be migratory.Logical formLearned from2 sentences. (Bat populations) can be migratory.Logical formLearned from2 sentences. (Redhead ducks) can be migratory.Logical formLearned from2 sentences. Migratory birds may undergo a taking.Logical formLearned from2 sentences. An ecology can be migratory.Logical formLearned from2 sentences. Some species of migratory birds may visit an area.Logical formLearned from2 sentences. An outbreak can be in migratory birds.Logical formLearned from2 sentences. Die-offs can be constituted-of-or-filled-with migratory birds.Logical formLearned from2 sentences. Die-offs of migratory birds may be considered unusual.Logical formLearned from2 sentences. Species. can be migratory.Logical formLearned from2 sentences. Polar bears can be constituted-of-or-filled-with migratory birds.Logical formLearned from2 sentences. The weather may affect chances of migratory birds.Logical formLearned from2 sentences. Migratory birds may have potential.Logical formLearned from2 sentences. An insect can be migratory.Logical formLearned from2 sentences. Emphasis can be on migratory birds.Logical formLearned from2 sentences.