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The " Ptyonoprogne " species construct an open mud nest and therefore belong to the latter group ; " Hirundo " species also build open nests , " Delichon " house martins have a closed nest , and the " Cecropis " and " Petrochelidon " swallows have retort-like closed nests with an entrance tunnel .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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