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The Breeding Bird Survey (BBS) provides better trend data for this species than for many other marsh birds, presumably due to relatively higher rates of spontaneous unsolicited vocalizations. BBS results suggest a moderate increase in abundance in Canada since 1970 while, within the densely-occupied Prairie Pothole Bird Conservation Region (BCR), numbers have increased by 63% (all BCRs with reasonably reliable BBS results are displayed below). However, BBS results in both areas show large inter-annual fluctuations (see graph). The increase in the national trend is largely due to a high count in 2012, but the overall pattern suggests little overall change in abundance since the early 1970s. Both the Great Lakes and the Ontario Marsh Bird Monitoring programs suggest decreases in abundance (since 1995 and 2004, respectively) in the area covered by these surveys, indicating possible regional and/or temporal variation in population trends. Given the contrasting results and because passive surveys, such as the BBS, do not detect this secretive species as well as targeted searches with call-playback (methods being increasingly applied in regional atlas and marsh surveys; e.g. Tozer 2007b), its nation-wide status is perhaps best assessed as having shown little change relative to 1970, but the reliability of this assessment is considered only medium. For more detailed information on Sora, see the 2014 Population Status of Migratory Game Birds in Canada report.
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
Additional information on: Great Lakes Marsh Monitoring Program
Additional information on: Quebec Marsh Monitoring Program
Assessment date: 2013
