The Breeding Bird Survey (BBS) is the most reliable survey for the Yellow-headed Blackbird, with good coverage of the species' population in Canada. BBS results indicate that the national population has experienced little change in abundance compared to 1970. However, within that period, numbers have fluctuated and temporal trends have varied. The population showed a variable but general decrease until the 2000s, at which point it began to increase through to the present. Trends vary among regions as well. The Prairie Potholes Bird Conservation Region (BCR), which hosts the highest density of blackbirds, increased by over 50% relative to 1970, while populations in the northern and western portions of the species' range show varying levels of decrease. All BCRs with reasonably reliable data are displayed below. Although the Yellow-headed Blackbird periodically dipped below the lowest acceptable level relative to its national population goal between 1998–2010 (see BBS Canada graph below), it is currently at an acceptable level.
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
