Chickadees, survivalists extraordinaire

It seems likely that weather is the only killer so devoid of both humor and dimension as to kill a chickadee.”

Aldo Leopold wrote this line back in 1949 in his incredibly influential book, A Sand County Almanac.  He was commenting on the extraordinary longevity of chickadee 65290, a bird that had survived for at least 5 years following its banding in 1937.  Little 65290 may have been extraordinary, but a brief walk in the winter New England woods will rapidly convince you that chickadees as a group are exceptionally resilient little creatures.

Chickadee in the spring sun

Chickadees are very vocal, calling to each other throughout the year. You can hear some of their calls at the Cornell Bird Lab website.  Chickadees often travel in loose flocks, flitting about, hanging upside down from branches, stealing insects from spiders, scrounging for seeds, and chasing each other about in the forest like a group of excited 5 year old children just released from a long, boring bus ride.  Their colors are subdued, yet distinctive: black, gray, white, often with a hint of yellow or tan on their underbellies.

Chickadee acrobatics

Black-Capped Chickadees (Poecile atricapillus) are cold weather specialists with a home range extending from Alaska to New England and dipping as far south as the mountains of Arizona and New Mexico and along the spine of the southern Appalachians (map).  I find this is extraordinary.

There is a principle of physics called the square-cube theory that relates the volume of an object to its surface area.  Basically, this can be simplified to the idea that a mouse has more surface area compared to its volume than does an elephant, and that for every time you double the size of an object its mass goes up by eight times (Length x Width x Height).  In terms of survival in cold climates this is really important because smaller things lose their heat far faster than large things because of that ratio of surface area to volume.

Chickadees are tiny.  Their bodies are barely larger than a golf ball, and much of that is feathers.  All told they probably weight as much as an emaciated mouse, yet they live in a part of the world that is well below freezing for great portions of the year.  During the winter nights chickadees huddle in cavities in trees in semi-torpor, burning fat at a prodigious rate.  At first light they are up and spend the day searching for food.

Feeding Chickadee silhouette

All living things have to balance the payoff of their behavior with the potential risk that behavior carries.  Some species are extremely risk-averse, in political terms these species might be the Ron Paul’s of the world, insisting on a gold based currency.  Chickadees are the opposite, they are inquisitive, curious, bold, and fearless.  As in many animals, their willingness to take risks is dependent on availability of resources.  You see this in humans, a far greater proportion of low income people spend their money on lottery tickets than high income people, despite the abysmally low chance of getting a winning ticket.  If you have few resources you will take more risks to get a large reward.  The costs of those risks are higher for those with fewer resources as well.  For chickadees this means of food and a place away from that humorless weather.

Keeping warm in winter takes more food than in summer, and food is more difficult to find.  Chickadees take risks to get that food, they investigate new objects almost as soon as they encounter them, they come closer to humans and stay longer than many other birds, and they try new things.

Traveling in groups is one way to offset the individual risks these brave little birds take.  More companions means more eyes to watch for danger (and food as well), and chickadees have a very well developed warning system that alerts their companions not only to danger, but to the degree of danger.

The risks they take, their small size, and the harsh weather they endure takes its toll and chickadees do not live long, hence Aldo’s comments on chickadee 65290.

Chickadee and hungry young

Chickadees may not live long, but their lives seem bright and full of vibrancy.  They are a reminder of the importance of curiosity, companionship, and communication.