Mike Jacobs: Chickadees have tricks to endure the cold
Here are the two big questions about these little birds: How do they survive the cold? And where do they go in the summer?
GILBY, N.D. — The black-capped chickadee may be the most familiar of our winter birds. Every feeder will have at least one, most likely several, and every wood patch will have a small flock. The chickadee is easily recognizable by its small size and its facial pattern, a large patch of white below its black crown and above its black bib. The chickadee’s call is unique, as well, a chirped rendition of its name.
Nevertheless, the chickadee is a bird of mystery. Here are the two big questions about these little birds:
How do they survive the cold?
And where do they go in the summer?
The answer to the first question is that chickadees are superbly well adapted to survive cold weather. An online posting by the Montana Natural History Center gives a three-part answer. Chickadees are well insulated, they’re active and they have good memories.
Each of these is remarkable by itself.
Insulation first. Chickadees have a layer of feathers half an inch thick. These trap warm air against their small bodies. What’s more, chickadees can regulate their body temperature, maintaining it at 100 degrees during the day and reducing it at night. This semi-torpid state conserves energy.
Everyone who’s watched chickadees knows that they keep busy. They haul away seeds, several at a time, and they hide them one at a time, each in a separate place. And they remember where they are.
This is the most astonishing thing about chickadees. They can change the size of their brains, shedding some brain cells late in the season and replacing them with what we might call memory cells, enough of these to store the location of each of the several thousand seeds they store away.
This practice is called “scatter hoarding,” and it’s not unique to chickadees. Blue jays do it, too. They make a morning’s work of hauling unsalted peanuts from a pan on our deck.
Chickadees haul away a lot of sunflower seeds, up to 1,000 a day. At that rate, their total haul might reach more than 100,000 seeds in a normal winter. Each of these is deposited in some crevice somewhere nearby, ready to be recovered.
These little birds are voracious eaters, eating almost constantly, so the hoard is critical to their survival.
Despite these adaptations, mortality is high among chickadees. .
All of this means that chickadees are not shy of the cold. They occur over a wide swath across the middle of North America, reaching interior Alaska and curving southeastward to Newfoundland. The southern limit of their range is a similar arch from southern Oregon to New Jersey, with a little extension through the Appalachian Mountains that reaches extreme northern Georgia.
This encompasses some of the coldest places on the continent, including the Red River Valley.
Chickadees are actually year-round residents here. They simply get shier and more secretive in nesting season. Although they are not daily visitors to my feeders in summer, at least one chickadee will show up from time to time. This suggests they are nesting nearby, perhaps in a hole in one of the trees in the shelterbelts that surround the place that Suezette and I share west of Gilby, about 30 miles northwest of Grand Forks.
Chickadees are monogamous, and pair bonds are formed throughout the year, the monograph on the species in the American Ornithological Society’s series “The Birds of North America” informs me.
They maintain a large territory, averaging 5.3 hectares or about 13 acres. Winter flocks are hierarchical.
Yet, chickadees are social birds, occurring in flocks up to 14 or more and often with other species, including nuthatches and downy woodpeckers. They appear to have a symbiotic relationship with the woodpeckers, which respond to chickadee defense calls and may provide cracks in which chickadees stash seeds.
While chickadees are regular at our feeder array – numbering as many as six on some days – they are far from the most numerous of the birds that visit. That place belongs unquestionably to the redpolls, which now number at least 100. To be honest, that’s a guess. Redpolls are flighty. Sometimes, they seem to cover the back yard in lively groups. I’ve managed to estimate the number of birds in these flocks, but individual birds move continuously, it seems to me, from one group to another.
So, counting them is impossible.
Trust me on this, though. This is a stand-out year for redpolls. They’ll hang around until early spring, about the time the snow finally disappears, and head to the very northern limits of the continent.
Jacobs is a retired publisher and editor of the Herald. Reach him at firstname.lastname@example.org.