Autumn is a time for change and colour
Yukon Wildlife Viewing (With Carrie McClelland)
Carrie McClelland is the lead education and outreach biologist with the Government of Yukon Department of Environment. In the fall she loves going for walks and “leaf peeping” (viewing the changing colours of the leaves).
Summer may be over, but fall is an exciting time to do some wildlife viewing
Throughout the summer, Yukoners enjoy exploring trails and waterways across the territory, catching a glimpse of a moose across a pond, smelling the rich Labrador tea after a rain, or listening to the wind shake the leaves of trembling aspen. But everything has a season, and seeing that first yellow leaf can make us grimace, especially in the North when it feels like summer has only just begun. As the days shorten and the temperatures fall, plants and animals go through changes in advance of winter.
It ain’t easy being green
Green plants are the original solar panels. Leaves contain chlorophyll, a chemical that allows plants to absorb sunlight. But chlorophyll absorbs only blue and red wavelengths (green wavelengths are reflected, which is why plants look green to our eyes). Plants take carbon dioxide and water and add a dose of sunlight to create the sugars they need in order to grow.
All living things in the North must somehow survive cold, dark winters, and plants are no different. Plants protect their cells by shutting down their circulatory systems, stopping the flow of water, sugars and chemicals to their “extremities.” Chlorophyll is cut off from the leaves, so green wavelengths are no longer being reflected. It is in fall when the true colours of plants shine through. The yellow, oranges and reds that you see are a result of carotenoids and flavonoids (pigments) that are always present in plants but just hidden all summer by the green wavelengths that are reflecting.
Fall colours start early in the alpine, in mid- to late August. Low shrubs, such as dwarf birch (sometimes referred to as buck brush), turn a brilliant red. Meanwhile, the willows are changing to yellow, and smaller shrubs will be everything in-between. At lower elevations, green leaves are still busy with photosynthesis so you can still enjoy the last days of summer.
The Golden Encore
Into September, the willows, trembling aspens, balsam poplars and tamaracks turn a brilliant golden yellow. Hillsides of evergreen trees will be dotted with patches of yellow as these trees shut down their energy centres and brace for winter. Though snow may have already dusted the alpine, lower elevations are a bit behind and the later display of yellow is sometimes known as the Golden Encore. One of the best places to see this display is in the young forests of the Takhini Valley or in the Fox Lake/Braeburn area. On a bright fall day, the hills practically glow with their own light, giving us a little encore of plant beauty before settling down for a long winter’s nap.
Animals are changing too
Plants aren’t the only ones preparing for winter. Ptarmigan, ermine/least weasel, Arctic foxes and snowshoe hares all change their colours to white, to camouflage in the snow. In the fall, you might catch one of these critters mid-change, looking rather mottled, with patches of white on their coats. If the snow is late in arriving, their white forms stick out on a brown landscape, making them quite visible and vulnerable to predators. Snowshoe hares are around the peak of their population cycle, so you might have a good chance of spotting rabbits as the leaves fall off of the trees and shrubs and as their white coats stand out.
Another sure sign that winter is coming are the flashes of red that are zooming up rivers and creeks. Salmon have returned from the ocean to spawn. Salmon are silvery when they live in the ocean, but when they begin the long migration back upstream, their colours change. It’s believed this is to attract a mate—similar to the breeding plumage of birds in spring. Being bright and flashy attracts a lot of attention and signals their readiness to spawn.
Let’s get outside!
Summer may be over, but fall is an exciting time to do some wildlife viewing. The changing landscape has lots to show us as plants and animals prepare for winter. You can join in our final Wild Discoveries events of the season, including a tour to the Fox Lake Burn where you can experience the Golden Encore. Visit yukon.ca/wild-discoveries for event listings.
