Why Do Chickadees Say Chickadee? Alarm Calls Decoded

A call that gave the bird its name

The black-capped chickadee and its close relatives in North America are named after their best-known sound. Both males and females give the “chick-a-dee-dee-dee” call throughout the year, in summer woods, on snowy winter days and at bird feeders.

The call has many uses. Members of a winter flock call softly to keep in contact as they move through the trees, birds call when they find food or arrive at a feeder, and the same call, given louder and with more dee notes, raises the alarm about a predator. Because chickadees feed in dense branches where they often cannot see each other, sound is their main way of staying together.

How the call is built

The chick-a-dee call sounds simple, but scientists have studied it since the 1970s and found that it is one of the most complex calls of any bird. It is made of up to four types of notes, labeled A, B, C and D. The A, B and C notes make up the “chick-a” part, and the D notes are the repeated “dee”.

The notes always come in the same order, A then B then C then D, but each type can be left out or repeated. That gives chickadees a huge number of possible combinations, from a short “chick-dee” to a call with many A notes or a long string of dees. Researchers compare this to a simple grammar, because the order of the parts is fixed while their number varies, and different combinations seem to carry different meanings.

More dees, more danger

In 2005, a team of American biologists published a study in the journal Science on how chickadees warn each other about predators. They exposed captive chickadees to more than a dozen species of owls and hawks and recorded the calls the birds made, analyzing more than 5,000 alarm calls.

The results were surprising. Chickadees did not simply call louder for bigger predators. Instead, small, agile predators that are most dangerous to a chickadee, such as the northern pygmy-owl, triggered calls with more dee notes than large, slow predators such as the great horned owl, which cannot easily catch such a nimble bird. Calls about the most dangerous predators also had shorter gaps between the “chick” and “dee” parts.

When other chickadees heard recordings of these calls, they reacted accordingly: high-threat calls drew them in to mob the predator more strongly. Mobbing means gathering around a perched predator, calling loudly and flying at it, which usually drives it away.

The “seet” call for flying hawks

The chick-a-dee call is mostly used for perched predators, which can be mobbed safely. When a hawk is flying, chickadees use a different alarm, a soft, high-pitched “seet”. Birds that hear it freeze or dive into cover rather than gathering to mob.

The seet call is thin and high, which makes it hard for a hawk to pinpoint where it came from. Many small songbirds around the world use similar high, thin calls when a raptor is flying overhead.

The fee-bee song

The chickadee’s song is quite different from its name call. It is a clear, sweet whistle of two notes, “fee-bee”, with the second note lower than the first. Males sing it mainly in late winter and spring to defend territories and attract mates, often early in the morning, much like the dawn chorus of other birds explained in why do birds sing at dawn?

Males also use the song in contests. A rival may match the pitch of a neighbor’s song as a challenge, and studies suggest that males who lose such contests, particularly high-ranking ones, can lose the interest of their mates. The song is remarkably uniform across most of the continent, although a few isolated populations, such as those on Martha’s Vineyard, sing unusual local versions.

Other birds are listening

Chickadees are the core of mixed-species flocks in fall and winter. Nuthatches, titmice, downy woodpeckers, kinglets, brown creepers and wintering warblers travel with them, partly because chickadees are so alert. When a chickadee sounds the alarm, the whole flock reacts.

Experiments have shown that red-breasted nuthatches respond more strongly to chickadee calls that signal a dangerous predator than to calls about a less dangerous one, so they understand at least part of the code. Detailed information in a predator call is not unique to chickadees: the Japanese tit, a relative in Asia, also combines call notes in a set order with different meanings.

Black-capped vs Carolina chickadee calls

The Carolina chickadee of the southeastern United States looks almost identical to the black-capped chickadee, and its sounds are the easiest way to tell them apart. Its chick-a-dee call is faster and higher-pitched, and its song usually has four notes, “fee-bee fee-bay”, instead of two.

Where the two species meet, in a narrow belt from Kansas to New Jersey, some birds hybridize and may sing mixed or confusing songs. Chickadee calls are also a key part of how these birds survive cold weather together, as described in how do chickadees survive winter?