The State of Boreal Chickadees
Regionally: Slightly increasing

The mean (thick, dark red line) annual estimate of the Boreal Chickadee abundance within the immediate areas surrounding ~750 Mountain Birdwatch sampling stations. The vertical bars represent the 95% Bayesian credible interval (a measure of the uncertainty around the abundance estimates).
In our region, sizable populations of Boreal Chickadees only occur in Maine, New Hampshire, and the Adirondacks of New York. Mountain Birdwatch data suggest that Boreal Chickadee populations in the northeastern United States have been gradually increasing since 2010 at a mean annual rate of 4.19% (95% Bayesian credible interval [BCI] = 0.24% to 8.48%). The North American Breeding Bird Survey results also support these trends over the last decade, specifically, but Boreal Chickadee numbers have overall declined by >50% since the 1970s in our Northern Atlantic Forest bird conservation region.
Globally: Declining
Because they occupy remote areas without road access, and because they tend to be quiet and secretive during the breeding season, Boreal Chickadees are not well-monitored by the Breeding Bird Survey. Available data, though, suggest that populations of Boreal Chickadees have broadly declined, since the late 1960s, across most of the United States and Canada with the exception of Alaska and northwest Canada.
Boreal Chickadee habitat is at risk of disappearance due to climate change. Recent climate modeling by Audubon, predicts that >50% of the current range of Boreal Chickadees will be lost over the next 100 years as temperatures increase. By the end of this century, it is probable that Boreal Chickadees will no longer occur in the lower 48 states.