Bittern Blog http://blog.lib.umn.edu/brow0491/bittern/ Bitterns en-us 2004-05-02T15:31:57-06:00 Bittern Surveys http://blog.lib.umn.edu/brow0491/bittern/000601.html 2.0.TX;2-F">Call-response surveys to monitor marsh bird population trends.... brow0491 2004-05-02T15:31:57-06:00