In Canada, the Breeding Bird Survey (BBS) is the best source of information to monitor the population of Carolina Wren, despite a small sample size that causes poor precision in the trend estimate. BBS results for Canada show annual fluctuations in the population, but suggest an overall large increase in numbers since 1970. Most of the breeding population occurs in southern Ontario, where the Atlas of the Breeding Birds of Ontario detected a large increase in occurrence between Atlas periods (these results are now somewhat dated). The main breeding population of Carolina Wren in the United States is monitored well by the BBS, which also indicates a steady increase in the continental population since 1970. The Carolina Wrenis at an acceptable level relative to its national population goal (see Canada graph below).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis