The State of Black-capped Chickadees
Northeastern US: Increasing
Most of us probably don’t think of Black-capped Chickadees as montane species, but this species can be found as high up as the top of Mt. Mansfield in Vermont. Mountain Birdwatch data suggest that Black-capped Chickadee numbers have increased at an annual rate of 3.14% (95% Bayesian credible interval = 0.25% to 6.16%) in the mountains of the northeastern United States since 2011. Black-capped Chickadees were not counted during the first ten years of Mountain Birdwatch, so whether recent increases reflect a long-term trend is unclear. However, in 2011 Black-capped Chickadees were essentially absent from the six Mountain Birdwatch routes in the Catskills. Our models estimate that there are now between 14 and 40 Black-capped Chickadees along these six routes in 2019, despite no obvious changes to the forest composition. Similar, in Maine, our models estimate that the population size Black-Capped Chickadees along Mountain Birdwatch routes has increased from ~8 to ~24 over the last decade. While these numbers are impressive, there are two points to keep in mind. 1) Black-capped Chickadees are still relatively uncommon in the spruce-fir zone along Mountain Birdwatch routes, so their trends are disproportionately affected by the addition or subtraction of a few individuals. We would probably want several thousand (as opposed to ~750) sampling stations to adequately describe the population dynamics of this species in our spruce-fir montane forests. 2) Black-capped Chickadees certainly breed in the spruce-fir zone at low densities, but the figure below suggests that Black-capped Chickadees may be erratic into this forest biome in some years. Boreal Chickadees, for example, are also known to be erratic from year-to-year: they may be locally common one year, and entirely absent the next.
Black-capped Chickadee numbers in our immediate study area have fluctuated throughout the last decade, but populations are currently higher than they were in 2011. Vertical orange bars estimate the uncertainty (95% Bayesian credible interval) in the estimate of abundance.
Globally: Increasing
The North American Breeding Bird Survey indicate the Black-capped Chickadee numbers are overall increasing across the United States and Canada. These increases, however, are largely confined to the upper Midwest and the eastern half of the species’ range; Black-capped Chickadees trends are negative in the lower Midwest and much of the western US and Canada.
Black-capped Chickadee numbers have been stable across Canada and the United States according to the Breeding Bird Survey. Points indicate annual estimate of relative abundance; higher numbers mean more Black-capped Chickadees were counted in that year. Solid black lines above and below indicate the uncertainty around estimates of relative abundance. Figure provided by the United States Geological Survey.
Opportunities for Conservation
The global population of Black-capped Chickadees is large – probably about 43 million individuals are alive at any given time – and they can survive and reproduce successfully even in heavily developed landscapes. As such, Black-capped Chickadees are relatively secure from most foreseeable short-term threats.
The food that we provide in the form of seed and suet helps Black-capped Chickadees survive cold northern winters, but these measures obviously only benefit the chickadees co-inhabiting our backyards. Black-capped Chickadees also need safe places to nest, however, which is something that many backyards lack due to the presence of outdoor cats and a lack of suitable nesting sites. Black-capped Chickadees nest in holes, so providing nest boxes is one attractive option. Unless you must for safety reasons, don’t remove dead trees or trees with rotten limbs from your backyard or woodlot; Black-capped Chickadees will excavate nest holes in rotten wood, so keeping dead trees will increase the amount of nesting habitat. Keeping pet cats indoors at all times year-round, will also increase the survival of Black-capped Chickadees in our backyards.
