Should I stay or should I go?
Surviving the winter at high latitudes requires endurance, tenacity and some brains! Not all birds that breed in the Arctic choose to migrate to warmer climates in the fall — some prefer to stay right where they are!
A resident species of bird is one that does not migrate, but spends a full year in the same location. Resident birds have the ability to feed themselves and stay warm even when the mercury drops to 40 below zero. To contrary belief, birds do not migrate to southern locations because of the milder temperatures, but rather for a more reliable source of food.
Life above the Arctic Circle
The Arctic National Wildlife Refuge sits north of the Arctic Circle and is known for its stunning beauty and iconic wildlife including the 197,000-animal Porcupine caribou herd, glistening-white polar bears, and an assortment of bird species breeding during the short summer months. Once winter arrives, the landscape transforms into a windswept and desolate place where only the strong-willed can survive such environmental extremes.
The Arctic Refuge is home to many year-round resident bird species including: Spruce Grouse, Willow Ptarmigan, Rock Ptarmigan, Gyrfalcon, Snowy Owl, Northern Hawk-Owl, Boreal Owl, Canada Jay, Common Raven, Black-capped, Boreal, and Gray-headed Chickadees (rare), American Dipper, Pine Grosbeak, White-winged Crossbill, and Common and Hoary Redpolls.
Each species has a unique way of coping with nine months of winter and two months of pure darkness…
Canada Jay (Perisoreus canadensis) are able to nest in extraordinarily cold conditions — laying eggs in February and feeding chicks in March when food availability is scarce.
Northern Hawk-Owl (Surnia ulula) can detect prey moving 12 inches beneath the snow. Unlike other owl species, Northern Hawk-Owl are not silent when they fly nor do they have asymmetrical ear openings.
Common Redpoll (Acanthis flammea) feed on birch and alder seeds, consuming up to 40% of their body weight per day during the winter.
. . . but not many adaptations are as extraordinary as those of the Black-capped Chickadee!
Memory for Survival
A very common backyard bird across the west and northeastern United States, Black-capped Chickadees are one of the most adaptable songbird species when it comes to winter survival. Each fall, chickadees collect extra seeds, fruits and insects and store their collection, or cache, in hundreds of different locations from crevices in the bark of a tree to a cluster of spruce needles, or even nooks and crannies in human structures.
You may be asking yourself “How can a bird that only weighs as much as a AAA battery possibly remember where all the food is stored?” Well, it’s all in their brains!
The hippocampus is a mushroom-shaped cap that sits on top of the brain in birds, contrary to mammals that have two located on either side of the brain. The hippocampus is the spatial memory portion of the brain that allows animals to learn and remember specific locations. Surprisingly, scientists have discovered that the size of the hippocampus in chickadees actually varies depending on the latitude of where the bird spends the winter. The colder the location, the larger the hippocampus grows — reaching a maximum of 30% of their total brain size.
Shivering in the Silence
But there is more to the Black-capped Chickadee’s winter survival success. These birds are also capable of going into nightly hypothermia. During the day, chickadees consume more than their body needs, allowing them to reduce their metabolism at night and use the extra fat reserves to shiver and stay warm throughout the 18-hour nights of northern Alaska. The bird’s incredible use of fat reserves would be equivalent to an average human male loosing 9% or 15 pounds during a single night’s sleep.
If you live where the Black-capped Chickadees roam and have a feeder full of black oil sunflower seeds, I’m sure you’ve had more than a handful of chickadees pay you a visit. Feeding backyard birds with appropriate foods is one of America’s favorite pastimes (beside baseball of course!). During the winter, peanut butter and suet cakes are excellent high-protein food sources that are sure to attract the birds, but if you don’t time it right, you may get more than you bargained for. Feeding birds in the spring and summer when natural sources of food are available isn’t necessary but OK as long as nuisance bears are not an issue and feeders are cleaned out frequently to prevent bird seed and suet from spoiling in the heat. Backyard bird feeding can bring joy any time of year, but in the winter, birdwatching at feeders can be exceptionally rewarding.
It is true that birdwatching in the winter is less desirable. It not only requires extra layers but also extra patients. Depending on the location, there are usually few bird species, but this happens to be the perfect opportunity for people new to birding! With fewer species in the winter, beginners can learn bird vocalizations and appearances without being overwhelmed by hundreds of migratory species right from the start. Additionally, without leaves on the trees birds are much easier to observe. Check out the Cornell FeederWatch Cam for bird viewing from the comfort of your own couch!
Paradise in the darkness
Resident bird species overcome enormous feats to survive the winter months. Hundreds of miles from civilization, the Arctic National Wildlife Refuge provides some of the harshest conditions for overwintering birds, but with such extraordinary adaptations, it’s just another day in paradise for the Black-capped Chickadee.
Laura McDuffie is a Communication Specialist for The Great Basin Institute and USFWS External Affairs Alaska Region.
In Alaska we are shared stewards of world renowned natural resources and our nation’s last true wild places. Our hope is that each generation has the opportunity to live with, live from, discover and enjoy the wildness of this awe-inspiring land and the people who love and depend on it.