 Freeze or Burn Three days ago I sat outside and watched a medium sized bird fly from behind the house and quickly disappear into a gaping hole in the side of a tall, long-dead poplar tree. I glimpsed enough of the bird’s general colour and white rump flash to determine that the bird was a Flicker. Judging from its swift, deliberate flight, the bird had executed this maneuver many times. I watched the hole for a while but the Flicker never reemerged so I surmised that it planned to spend the rest of the night inside the tree. This was the first time that I’d ever seen a Flicker enter a tree cavity during winter but it didn’t come as a surprise because many creatures seek refuge from the cold. Chickadees, Nuthatches, and other small bird species often pass the dark hours sharing body heat in a small tree or stump cavity. During warmer months the South Cariboo is home to two hundred or more bird species. During winter the numbers of bird species drops to around forty. Those hardy species residing year round in the Cariboo have developed strategies which ensure survival. I would guess that about ninety-five percent of the Flicker population migrates to warmer, snow free climates (not necessarily vastly further away but milder for sure,) and it is hard to imagine why all the Flickers don’t leave when given the chance. Bald Eagles also migrate southward to places such as the Fraser Valley, leaving behind a small percentage of their kind to the frozen, snow-covered Cariboo. How do various bird species decide which of their number stay behind? Who will the harsh climate sustain? I imagine Bald Eagles get by quite well. They can fly great distances and take advantage of animals killed on the road, and animals killed by the unforgiving winter. Eagles cannot access the fish typically eaten in summer however during winter there are many instances of ice fishermen throwing coarse fish onto the ice for the ever watchful Eagles to eat. Crossbills thrive on treetop evergreen cones and have no trouble finding summer, or winter food sources. However, a Flicker lingering over winter faces daunting challenges. It is effectively a ground feeding Woodpecker whose favourite food, ants, are covered with snow. If the Flicker wants to survive it must resort to feeding on tree trunks in the manner of Hairy and Downy Woodpeckers. It does manage the necessary wood-work but it must be quite a challenge to modify feeding behaviour during the winter season. Human-created feeders and landfill sites also impact how many of a species migrate to warmer climes. Who knows how many Red-winged Blackbirds, Crows, Starlings, or Flickers would survive a Cariboo winter without their artificial food supply? The subject of humans’ artificially sustaining or augmenting birds is always contentious. Some suggest that feeding birds is unnatural. I don’t hold such a view and claim, vehemently at times, that humans have supplanted much of the natural habitat and with the loss of the natural habitat went many wild-bird feeding opportunities. The food we supply offsets just a small portion of the loss birds sustained when we began modifying landscapes to our own needs. Early in the twentieth century the Northern Flicker was divided into Red-shafted Flickers and Yellow-shafted Flickers. The red was a western bird (west of the Rockies) and the yellow was an eastern bird (east of the Rockies.) The Red and the Yellow-shafted Flicker were not true separate species; where they converged they were able to mate and produce variations of each race. The two races split when the ice sheet covering the North American continent forced the Flicker population apart, and over time two colour variations formed. After the ice sheet retreated the two species were kept apart by a great treeless plain. When settlers eventually populated the seemingly endless grasslands they planted trees and a number of tree dependent bird species filled in the gap. And so the Yellow-shafted Flicker met the Red-shafted Flicker. The ‘purity’ of the colour variations no longer holds true and both races are now named Northern Flicker. Again, humans had taken a hand in changing the world of birds as it had been for years. I like to think that humankind is no different than a glacier, that is, just another force which causes change. It is difficult to say whether a change wrought by humans or a change wrought by “mother nature” is good or bad. Even good intentions toward wild creatures don’t always work out. As the Flicker hides in the tree for the night, all organisms face the challenge of survival. That a Flicker still exists is a testament to being able to hold enough of what it needs. Humans too, are governed by the same rules. Without a suitable environment of air, water, and food, our species also will cease to exist. To e-mail Tom CLICK HERE To look at previous column CLICK HERE |
