The best source of monitoring information for Cassin's Finch is the Breeding Bird Survey (BBS). While the species' breeding population is well covered by the BBS, their flocking and nomadic nature creates high variance in the data and lowers precision of trend estimates. The BBS trend suggests a 56% decrease in numbers since about 1970, but the precision of the trend estimate is moderate, thus this assessment is considered to be of medium reliability. However, the large decrease seen in the continental population (see table below) suggests that the decline in Canada is real and not a result of birds moving across the border. The Cassin's Finch is below the lowest acceptable level relative to its national population goal (see Canada graph below).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
