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It’s in your nature: How do they do it? Brrr …

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    A mourning dove, a common year-round resident, displays the feather fluffing it uses on a cold January morning.

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    Tree swallows, summer residents here, found a sunny limb and fluffed their feathers to keep warm on a frosty late March morning. BARRY REED/SPECIAL TO THE TIMES NEWS

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    A black-capped chickadee, nearly double the weight of a golden-crowned kinglet (weighing slightly more than one penny), somehow also makes it through some terribly cold winter temperatures.

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    Blue jays, about 20 times heavier than a kinglet, migrate from southern Canada to find our winter temperatures more bearable.

Published December 08. 2018 07:30AM

A few days ago I bundled up to prepare for a cold 11 hours sitting in the Carbon County woodlands. I donned felt shoes, three pairs of socks and a toe warmer packet. For the remainder of my body, I had a “heavy” insulated winter coat, chamois shirt, and three layers of thermal and wicking under layers. A heavy woolen hat completed my outfit. Within a few hours, my feet were cold and I shivered a number of times throughout the day.

Meanwhile, small flocks of winter birds fed nearby in the tree tops and among the now bare branches. They didn’t have the multiple layers like me, and seemed to pay no heed to the 30-degree temperature and 30 mph winds. They looked like they were just as comfortable in December as they are in the summer months. Most of those birds were either black-capped chickadees or golden-crowned kinglets. The former weigh about 9 grams (weight of two pennies), while the kinglets weigh in at 5 grams, even smaller. How do they withstand a shivering cold night pressed against a branch from 4:45 p.m. until shortly before sunrise?

The smaller an animal’s body size, the harder it is for it to maintain its body temperature in the cold. That is why, the species are generally larger as you go farther north in latitude.

Some deer hunters know that a white-tailed buck from Maine or Alberta is larger than most bucks in Pennsylvania. Likewise, most Pennsylvania whitetails are larger than Alabama deer. The largest owl species are found in the far north; great gray owls and snowy owls for example. Moose and caribou, both northern species, are large. Yet how does a tiny golden-crowned kinglet still survive bitter cold?

The kinglet needs to eat two times its body weight in a day. It has a heart rate of 1,000 times a minute, which drops to about 500 beats a minute through the long winter night. So having plenty of fuel is one way to survive.

Here is another. I just listed all the layers of clothing I needed to try to stay warm. For me, layering is the key. Each layer of clothing traps a minute layer of insulating air. Air is a good insulator. Birds in the cold use the same method. (However, not thermal long johns.)

When it gets very cold you may have noticed birds look bulkier. Well they haven’t gained weight. They are fluffing their feathers.

Birds have a tiny erector muscle attached to the feather base. When it is cold, this muscle contracts, pulling the feather up and away from the body, trapping critical air close to them to help in insulation. We have the same process. When you get a chill you often get “goose bumps.” Each of our hairs gets pulled up in a futile attempt to help warm us. (We no longer have a thick, hairy covering, but we still have still the erector muscles.)

Birds’ feet, most notably those of ducks and geese, also have veins and arteries very close together in their legs, helping to keep all the blood warmer. Thus feet, perched on a snowy limb at 25 degrees or in a pond that is 33 degrees, are able to withstand the cold much better.

I can’t explain all the reasons a kinglet or chickadee can survive so well, but hopefully I have given you a few of the answers. Next time you are walking from your car to the grocery store on a January day all bundled up to the nines, remember that there are thousands of small birds somehow surviving without our creature comforts.

Test Your Outdoor Knowledge: __________ are year-round residents in the Times News region. A. black-capped chickadee, B. tufted titmouse, C. downy woodpecker, D. all of these, E. none of these

Last Week’s Trivia Answer: The woodcock is also known as a timber doodle.

Contact Barry Reed at

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