Nature Notes: Black-capped Chickadee
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They are everywhere, so many of them that it is easy to take them for granted. Their numbers have been increasing lately, something for which we can be grateful since they are important to our health and well-being. Especially this winter, life without them would be quite different.
No, I am not referring to health care workers in PPE, although we are certainly lucky to have them. I’m talking about one of the smallest birds around in winter, and also the friendliest. Look around any large parking lot and you will see dozens of them since they grace the official license plates of Maine, having been designated our state bird in 1927. It is, of course, the diminutive black-capped chickadee, the second most likely bird seen in your backyard after the American crow.
While the population of many songbirds has fallen rapidly in the last five decades, the black-capped chickadee is doing well. They may be a beneficiary of climate change, since mild winters are easier on small birds, but supplemental feeding by humans is certainly a factor in chickadee survival in the northern US and Canada. Unlike many other songbirds, the black-capped chickadee is not given to winter migration except in years when there is an excess of young birds and a shortage of food.
It is easy to love chickadees, these tiny balls of good-natured fluff in nearly constant motion. They are not only tolerant of humans but sometimes quite curious, willing to take food from your hand (with some time to gain confidence in you). Trying to capture high quality photos of these birds is an exercise in endless rejected shots, since they bounce from one perch to another in short order (thank goodness for digital cameras).
If I was only five inches tall and weighed less than half of an ounce, I would be pretty skittish in a neighborhood occupied by bullying blue jays and predatory hawks, falcons and house cats. Whether they are hanging upside down at your feeder or skittering around in your shrubs, black-capped chickadees are a constant source of joy.
If you like challenging pronunciations, Wikipedia reports that in the Abenaki language the bird is known as “kejegigilhasis.” The scientific name is Poecile atricapillus, with the latter word derived from the Latin for “black haired.” The large black head and black bib on a short neck are distinctive against the white cheeks and chest. The back and wing feathers are soft gray trimmed in white. The buff-colored sides can vary from light tan to a rufous red in some birds. Males and females look alike, with the only difference being that the male is slightly larger. The bill is a sharp stub of black that appears almost too small, but they are adept at eating the toughest of seeds. I enjoy watching them rocking back on their heels with a sunflower seed clinched between their feet, hammering away until they can pick out the nutritious inner bits.
The chickadee is comfortable in a wide range of habitats but is most comfortable in mixed deciduous forests or areas thick with bushes and shrubs. If food is readily available the birds will frequent marshes or weed-choked fields. From the spring breeding season through autumn the majority of their diet is insects, spiders, caterpillars and other animal foods. These foods are especially important for feeding their young. In the winter months the diet shifts to include a wide variety of seeds and berries, along with insect eggs and pupae and bits of fat and meat from carrion.
At your feeders the chickadees are flexible, taking just about any food you make available. They won’t settle in for a long meal like the finches, but prefer to grab something and fly off to a nearby tree. Like the nuthatches and tits, chickadees love to cache food in niches on trees as if saving for a rainy day when you forget to refill your feeder. Tests have shown that the birds have an excellent memory and are able to retrieve these bits of food with great accuracy, unless some thief has snatched it away. Researcher Colin Saldanha at Lehigh University discovered that the chickadee’s hippocampus, the part of the brain responsible for spatial memory, expands up to 30 percent in winter to keep track of all the hidden food!
Black-capped chickadees are cavity nesters and prefer to use existing holes in birch or alder trees, often taking over abandoned woodpecker holes. In standing dead snags with soft wood the birds are capable of creating their own cavities. They also might use a nesting box if in a suitable location. As in most species, the female selects the final nest site and prepares her nest using moss, grasses or small twigs for the base, and soft materials like feathers or bits of mammal fur for the lining. In May I watched a pair preparing a nest in an old white birch in our yard, using a tiny opening at least 30 feet in the air. Back and forth the birds flew for days carrying small bits of material in their mouths. It was always the female who entered the hole to do the decorating.
Breeding and nesting take place between April and June, with a second clutch of eggs laid only if the first clutch fails. Pairs form in autumn, and the male is active throughout the process of rearing young. While the female is incubating six to eight eggs for nearly two weeks, the male brings her food. Both parents feed the hatchlings, using food to lure the young from the nest about two weeks after birth. Feeding will continue for a few weeks until the small birds are capable of fending for themselves.
You might wonder how such a tiny bird can live through cold northern winters. Well-known author and biology professor Bernd Heinrich has long studied chickadees and reports some fascinating survival techniques. First, the birds have the ability to fluff out their feathers to trap body heat. Chickadees, like other animals, are careful to restrict their foraging in periods of very cold or windy weather since they are apt to lose more energy than they gain from feeding. Taking shelter in thick cover is better than risking exposure. These birds also have developed the ability to lower their body temperature at night from a normal 108 degrees F to as low as 86 degrees F, thereby saving energy. Finally, the chickadees have adapted such that their feet are allowed to chill to nearly freezing temperatures and remain flexible. Blood vessels keep the tissues in their legs and feet warm enough to avoid frostbite without wasting valuable heat from the core of their bodies.
Step outside almost anywhere in Harpswell and it will not take long before you hear the chickadees. Of more than a dozen sounds logged by scientists, two calls are most common. In springtime, you often hear the short two note call “fee’ bee,” sometimes extended to “fee’ bee bee.” This is primarily a male calling for a potential mate or to defend his territory but females have also been recorded making this call in the wild. Throughout the year you have surely heard the longer “chick a’ dee dee dee.” This call is sometimes a warning or alert call by which a chickadee lets others in a flock know of potential danger nearby. Scientists have learned that the more concerning the threat, the longer the call becomes, with one bird adding 23 “dees” after spotting a nearby owl!
Chickadees are active, acrobatic flyers and are often seen in mixed flocks with other birds such as woodpeckers, nuthatches, warblers and vireos. This is probably driven by the wish to find strength in numbers, with more eyes to spot predators.
In the fifty years up to 2015, black-capped chickadees managed to gain in population here in the East, while the Western population dropped slightly. Partners in Flight estimates their numbers at more than 41 million, with just under half living in the US. This means there are no current concerns about the state of the chickadee’s population, although they are susceptible to the same risks as other small birds if global warming and pollution continue unchecked, or forestry practices limit the number of dead trees available for nesting.
Maine is not the only place to favor the black-capped chickadee. Both Massachusetts and New Brunswick have given them official status. There has been a bit of a kerfuffle in our state legislature in recent years as some people argued for removing the black-capped chickadee as the official state bird. The argument is that the boreal chickadee of northern Maine is more distinctively representative of our state. Given the prevalence of the black-capped chickadee in more populous southern Maine, and their winning ways, I suspect that the boreal chickadee has lost this round. Personally, I am happy to enjoy them both!