Black-capped Chickadee, adult, January in St. Louis County, Minnesota. Photo by Brian E. Small
Widespread throughout the northern United States and Canada, the black-capped chickadee is a familiar backyard bird to millions. In most of its range it is among the easiest birds to identify, but in a few areas it is among the most difficult.
Most of the seven species of North American chickadees are easy to tell apart. But the Carolina chickadee is extremely similar to the black-capped chickadee, and their ranges meet along a border that stretches from the Atlantic coast to the Great Plains.
Carolina Chickadees are on average smaller than Black-capped Chickadees. However, both species vary in size regionally and individually; the smaller Carolinas are in the southern part of their range, so size has only limited value for identification where the two species meet. The blackcap also tends to appear a bit longer and larger-headed than the Carolina.
Their voices differ. The Black-capped Chickadee sings two or three syllables: to haveOr see-bee-ee, with the first note higher. Carolina Chickadee sings four syllables, the first and third very high: see-bee-see-berry. call notes,chick-a-dee-dee-deetend to be faster and higher as shown by Carolina, but are variable in both species.
When the birds are in fresh plumage (autumn and winter), the shape of the wings is the most visible difference. The greater coverts have distinctly paler broad edges in the black-headed coverts, creating a pale panel on the wing and connecting to the whitish edges of the tertials and secondaries. The effect is that of a whitish “hockey stick” on the dark gray wing. In the Carolina Chickadee, the greater coverts are essentially the same gray as the back, and the tertial edges are not as pale as in the Black-capped Chickadee. These differences become obscure in late spring, when adults of both species show worn, dull plumage.
In addition to its wing pattern, the black-capped bird tends to be a more colorful bird. It features an olive hue on the back, where the Carolina is simply gray. The buff wash on the flanks is generally stronger in the Black-headed Man. The white cheeks often appear brighter white in the black-headed cat and extend farther back, to the edge of the neck. On Carolinas, the white cheeks may change to pale gray towards the rear. All of these differences are subtle, but in combination they can make a blackhead visibly brighter when surrounded by Carolina chickadees.
In some years, large autumn flocks of Black-headed Man are seen in eastern Canada and the northern states. These movements do not extend very far south, but they often cause some individuals to appear a little south of the normal range. Birders near the northern edge of Carolina chickadee territory should keep an eye out for a slightly larger, more colorful stranger joining their local chickadee flock in winter.
The range boundary between the Black-capped Chickadee and the Carolina is marked by an area in which most chickadees are hybrids. If you are in this zone, you may witness remarkable changes over time; see box below.
What to look for
The size and the shape. Slightly larger, with larger head and longer tail than Carolina Chickadee.
General colors. Mainly grey, black and white, but with olive sheen on the back and buff on the flanks in cool plumage.
Great blankets. These wing feathers have broad, pale edges, paler than the back. evident in fresh fall and winter plumage, becoming faded and worn in late spring.
Flight feathers. Dark tertials, secondaries and rectrices have conspicuous white edges when fresh.
Face model. The shiny white patch on the cheeks extends to the edge of the nape.
Black-capped Chickadee, adult, January in St. Louis County, Minnesota
This bird’s posture may exaggerate the extent of the white patch on the cheek, but the brightness of the patch is no illusion. This cool plumaged winter bird has the subtle but classic markings that separate the black-capped chickadee from its Carolina cousin, including an olive tinge on the gray back and a warmer buff on the flanks. Note especially the wing pattern, with broad pale edges on the greater coverts and a white border on the tertials and other flight feathers. Irregular flights during some fall seasons bring a few black-capped individuals to areas south of the breeding range in winter. It’s worth keeping an eye on these wandering birds among Carolina chickadees at a bird feeder, where individuals can be closely studied.
See photos from Black-capped Chickadee readers
Carolina Chickadee, adult, September in Montgomery County, Texas
Carolina Chickadees moult in summer, so this September bird has very fresh plumage. Even so, the pattern of its wings presents little contrast. The edges of the tertials and secondaries are only slightly paler than the rest of the feathers, and the greater coverts are simply medium grey. On a black-headed bird with fresh plumage, the whitish edges of these feathers create a visible pattern. This bird is also less colorful overall than the black-headed bird, with a plain gray back without olive tones, only a faint buff wash on the flanks, and less extensive white on the cheeks. Carolinas are also on average slightly smaller and shorter-tailed than black-headed Carolinas. All these differences are subtle and difficult to perceive on the ground.
Mountain Chickadee, adult, June in San Bernardino County, California
The feathers of this mountain chickadee appear dull and worn compared to the black-capped and Carolina chickadees on the previous page. It’s just the result of the season; all adult tits begin to look ragged in the summer, when all their feathers are several months old. When a mountain tit has molted and is in fresh plumage (autumn and winter), the white eyebrow stripe is remarkably evident, making the bird easy to identify. On a bird with worn plumage, this stripe (consisting of white feather tips) may be almost entirely obliterated. Black-capped chickadees and mountain chickadees overlap in parts of the West and have even been known to interbreed, so identifying them can sometimes be tricky.
Mexican Titmouse, adult, April in Cochise County, Arizona
Widespread in the mountains of Mexico, this chickadee only enters the United States in the Chiricahua Mountains of southeastern Arizona and the Animas Mountains of southwestern New Mexico. It is easily recognizable by its range, as no other tits are present in these mountains. At first glance it resembles the black-capped chickadee, but a closer look shows that the Mexican chickadee has a much more extensive black bib, extending to the chest, and a dark gray wash along the sides and flanks. It was one of the last bird species in the lower 48 states to reveal its nesting secrets; no ornithologist saw the Mexican chickadee’s nest and eggs until Herbert Brandt examined a nest in 1948.
A moving frontier
Two species of chickadees occur along a line stretching from western New Jersey to Kansas: the black-capped chickadees north of the line and the Carolinas south of it. Where they meet, they intersect, so the “pure” forms of the species are separated by a hybrid zone about 20 miles in diameter.
The fact that they interbreed does not mean that they belong to the same species. Hybrids have lower reproductive success and chances of survival than the parent species. The hybrid zone therefore remains narrow and acts as a sort of isolation mechanism.
This hybrid zone has gradually moved north. Historical information is sketchy and mostly unreliable, but we do know that in Ohio, for example, a northward spread of the Carolina chickadee was apparent as early as the 1930s. eastern Pennsylvania revealed that the hybrid zone is moving northward at a rate of about 7 miles every 10 years. At its northern limit, the chickadee population could shift from black-capped chickadees to Carolina hybrids within about three decades.
This change is linked to climate change. Black-capped chickadees are more cold hardy than Carolina chickadees. As average winter temperatures gradually increase, Carolina chickadees are able to survive winters farther north. Researchers from the Pennsylvania study found that temperature changes closely tracked the northward movement of the chickadee hybrid zone.
