During the winter months, my wife Aubrey and I take frequent walks through a wooded area near our home. We’re always on the lookout for wildlife, hoping to spot a rarity such as a short-tailed weasel, a striped skunk, a moose, or a bobcat, but usually have to settle for sightings of the few hardy, adaptable songbirds that are tough enough to tackle the seasonal winter cold. At this time of the year, many of these birds abandon their usual defence of breeding territories and instead travel together in temporary, mixed-species flocks. By altering their behaviour and temporarily foraging with others they benefit by having more eyes watching for potential avian predators while they are distracted with feeding. In many areas of Canada, the leaders of these roving, mixed-species flocks are chickadees which are then joined for variable amounts of time by nuthatches, woodpeckers and brown creepers. All are well adapted to the cold weather conditions and unpredictable feeding opportunities characteristic of winter.
The 16-cm (6-in) long downy woodpecker is the smallest woodpecker in North America weighing little more than a chocolate glazed Timbit from Tim Hortons. The male has a conspicuous red patch at the back of his head, otherwise, the sexes are identical.
Downies eat mainly insects, especially small wood-boring beetles hidden in cracks and crevices.
Because of its small size the lightweight downy can hunt along the slim outer branches of trees while larger, heavier woodpecker species must concentrate on trunks and thicker limbs.
The hairy and downy woodpeckers look almost identical, although the hairy is almost 50% longer and up to three times heavier than the downy. The pair are an example of convergent evolution in which unrelated species end up looking and behaving the same in response to similar environmental pressures. In the field, the size of the beak is a convenient way to distinguish between the two species. In the hairy woodpecker (shown on the left), the beak comprises half the distance between the back of the bird’s head and the tip of its beak, whereas the beak of the downy woodpecker, which is much smaller, only comprises a third of that distance.
Many woodpeckers, including this female hairy, have a thick screen of stiff feathers at the base of their beak to prevent wood chips from entering their nostrils when the birds are busy hammering and drilling for food.
In winter, in Alberta, three species of chickadees occur in the mixed coniferous-deciduous forest where Aubrey and I walk. There’s the uncommon mountain chickadee (pictured here), the rare boreal chickadee, a regular inhabitant of northern forests, and the black-capped chickadee which vastly outnumbers the other two. All are small, sociable, lively, inquisitive songbirds in which males and females look alike.
The plumage on a chickadee is much denser than on a migrant songbird of the same size. Its soft feathers may comprise 11 ½ per cent of its total body weight. But the chickadee pays a price for its thick insulating coat of feathers; the tiny bird is a notoriously weak flyer. All chickadees can further warm up by fluffing out their plumage. The raised feathers trap more air, which improves the insulating value by a further 30 to 50 per cent.
When foraging, the tiny birds are never still, constantly peering into clusters of needles, inspecting the shadowed crevices of ragged bark, hopping and flitting among the branches. In winter, they mainly feed on the eggs of spiders and insects, as well as the larvae of dormant insects, seeds, and dried berries.
All chickadees cache surplus food in times of plenty which they then consume later when food is scarce. In autumn they may store hundreds to thousands of food items in a single day.
The brown cap and rusty-coloured flanks are identifying features of the boreal chickadee. A caching boreal chickadee stores each food item in a separate site. Common hiding places include lichens, needle clusters, bark crevices, curled leaves, and the broken ends of branches. A quarter of the spruce seeds stored by boreal chickadees in Alaska were also secured with strands of silk scavenged from spider webs and insect cocoons. In the same Alaskan study, researchers watched the chickadees sometimes camouflage the stored food with a bark chip, some lichen, or a spruce needle.
Birds normally maintain a body temperature of 40 degrees C (104°F), but it is costly for them to keep the heat turned up that high, especially in winter. To conserve energy, many birds lower their internal thermostats at night. The smaller the bird, the more energy it can save by cooling down and the quicker it is able to warm up again next morning. The nighttime body temperature of a roosting boreal chickadee may drop to 30 degree C (86°F), earning the bird an energy savings of up to 45 percent.
Two species of nuthatches, the white-breasted, pictured here, and the smaller, red-breasted nuthatch, commonly travel with flocks of chickadees. The beaks of nuthatches are long and pointed, dramatically different from the small, conical beaks of chickadees.
Foraging nuthatches are unique in searching up and down on tree trunks whereas woodpeckers and brown creepers only search while hopping upwards.
Like woodpeckers, nuthatches search for dormant insects in the crevices of tree bark and by drilling small holes.
The large feet and long, curved claws on this red-breasted nuthatch help it to securely grip the bark when its climbing on vertical tree trunks.
By climbing down trees, a nuthatch may spot prey that is hidden from upward-facing foragers such as woodpeckers and brown creepers.
All chickadees, such as this black-capped chickadee, have especially strong leg muscles that enable them to feed acrobatically, sometimes even hanging upside down.
As mentioned earlier, chickadees typically form the nucleus of temporary winter flocks, and they help to keep the groups together by vocalizing frequently.
When a black-capped chickadee hides surplus food in a multitude of locations, called scatter hoarding, it greatly lessens the risk of theft. But, and this is a big but, the hoarder must remember hundreds, if not thousands, of storage sites afterwards. The hippocampus is the portion of the brain devoted, in part, to spatial memory. It’s no surprise that this part of the brain is larger in birds that cache, such as chickadees, than in those that don’t. What is surprising, however, is that the size of the hippocampus actually increases and decreases seasonally. In a 1994 pioneer study, the researchers found that the hippocampus of the black-capped chickadee showed the greatest increase in size in October, the precise time when the bird is caching and would need an improved spatial memory. Researcher Dr Bernd Heinrich wrote, “It now seems that birds can grow and shrink brain tissue as needed, thereby avoiding the expensive maintenance of tissue not in use.”
The brown creeper has long toes and curved claws like those of a nuthatch which both birds need to securely cling to bark. In the winter woods near our home, I rarely see a brown creeper. Their quiet demeanour and cryptic plumage make them hard to locate. Additionally, they often freeze when they perceive a threat.
Two small species of woodland owls are potential predators of winter flocks, the boreal owl (left) and the northern saw-whet. When either is spotted, the chickadees vociferously scold the owls, alerting other nearby birds which often join in the mobbing, driving the owl away.
About the Author – Dr. Wayne Lynch
For more than 40 years, Dr. Wayne Lynch has been writing about and photographing the wildlands of the world from the stark beauty of the Arctic and Antarctic to the lush rainforests of the tropics. Today, he is one of Canada’s best-known and most widely published nature writers and wildlife photographers. His photo credits include hundreds of magazine covers, thousands of calendar shots, and tens of thousands of images published in over 80 countries. He is also the author/photographer of more than 45 books for children as well as over 20 highly acclaimed natural history books for adults including Windswept: A Passionate View of the Prairie Grasslands; Penguins of the World; Bears: Monarchs of the Northern Wilderness; A is for Arctic: Natural Wonders of a Polar World; Wild Birds Across the Prairies; Planet Arctic: Life at the Top of the World; The Great Northern Kingdom: Life in the Boreal Forest; Owls of the United States and Canada: A Complete Guide to their Biology and Behavior; Penguins: The World’s Coolest Birds; Galapagos: A Traveler’s Introduction; A Celebration of Prairie Birds; and Bears of the North: A Year Inside Their Worlds. In 2022, he released Wildlife of the Rockies for Kids, and Loons: Treasured Symbols of the North. His books have won multiple awards and have been described as “a magical combination of words and images.”
Dr. Lynch has observed and photographed wildlife in over 70 countries and is a Fellow of the internationally recognized Explorers Club, headquartered in New York City. A Fellow is someone who has actively participated in exploration or has substantially enlarged the scope of human knowledge through scientific achievements and published reports, books, and articles. In 1997, Dr. Lynch was elected as a Fellow to the Arctic Institute of North America in recognition of his contributions to the knowledge of polar and subpolar regions. And since 1996 his biography has been included in Canada’s Who’s Who.
1)for your typical article on birds, what equipment do you use, or is standard for going out to capture pictures?
2) have you ever used one of the high telephoto camera/lenses?
like Nikon P1000 or 950??
Hi Clarence. I don’t use anything special for the bird photos. Most often I am using a 500 or 600mm telephoto. I have never used any of the cameras you mentioned. Sorry.
Wayne
An excellent review of our wintering birds and their habits. The pictures are a great help in seeing small differing details. Thank you so much for this very excellent study.
Thanks for the kind words.