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Although the nests of the " Ptyonoprogne " crag martins resembles those of typical " Hirundo " species like the barn swallow , the research showed that if " Delichon " , " Cecropis " and " Petrochelidon " are split from " Hirundo " , " Ptyonoprogne " should be also considered as a separate genus .
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Text: {0} 
Answer:
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