Rouge Valley Conservation Centre
Nature Notes
By Steve Gahbauer
January 2009
Trees and Climate Change.
Trees help moderate our climate and make it more comfortable while at the same time improving air quality. They do this in two ways: by shading homes and buildings, and by releasing large quantities of moisture (and oxygen) through their leaves. This transpiration effect allows trees to act like giant air conditioners which, combined with the shelter that trees provide from wind, means that the thousands of trees throughout the green-belt area help reduce both our energy requirements and the pollution resulting from burning fossil fuels.
In the early 1900s, the Ganaraska Forest taught us a lesson about the value of trees. It was then a large forest, covering the area from Lake Ontario to and across the Oak Ridges Moraine. Subsequent clearing of the forest, however, exposed the sand and gravel of the moraine. The results were hundreds of hectares of sand dunes, abandoned farms, and a mix of both low water levels and flooding – evidence of an ecosystem out of balance. In 1944, the government appointed a commission to address the impacts of deforestation and since then the Ganaraska Region Conservation Authority has helped plant more than five million trees to restore the forest and its water system. The Ganaraska Cobourg Creek Advisory Committee is doing some further work in that area and a technical report with recommendations is due later this year.
Forests and water storage areas help to absorb carbon dioxide and their interaction is vital for a healthy ecosystem. Natural areas like the Rouge headwaters in the Oak Ridges Moraine help store water and prevent flooding by first absorbing and then slowly releasing rain, snowmelt and runoff. One study found that a forest wetland can release up to half a million cubic metres per hectare per day into a region's groundwater supply. Another study found that less than half a hectare of wetland can store more than 6,000 cubic metres of floodwater; that's equal to about 38,000 full bathtubs of water. So, let's keep our forests and wetlands intact.
I cringe every time I learn about another tree being cut. We need them! A typical tree produces about 260 pounds of oxygen a year. Over a 50-year lifespan, an average tree performs $62,000 worth of air pollution control, recycles $37,500 worth of water, and prevents $31,250 worth of soil from erosion. And all this is for FREE. Killing a tree is not only a pain to the heart, it is stupid!
Birds and Winter.
Birds have numerous adaptations to help them cope with lean winters. Some band together in foraging flocks, others make periodic irruptions (sudden, food scarcity-driven temporary increases in the local population of migrant birds or animals) away from their normal ranges when food supplies run low. Just think of the otherwise unexplainable winter migrations of Great Gray Owls last year and Snowy Owls early this winter. Not all birds are like Chickadees and Gray Jays who collect and store food when it is plentiful and use these cashes when fresh food is not readily available.
Unfortunately, natural and seasonal fluctuations are not the only challenges our birds must overcome. Habitat degradation and loss are among leading causes of serious bird population declines. I have talked about it previously: over the last few decades, 20 of North America's most common species have been reduced by more than 50%, some by even up to 90%. Chimney Swifts, Bobolinks and Canada Warblers have also suffered from severe population declines.
On the plus side, we still can experience the arrival of the harbingers of winter, our regular winter wayfarers, in the dark days before the winter solstice. For millions of birds, their winter migration takes them much farther south, but for some passerines our area of Canada is quite enough. The delightful dark-eyed, ground-foraging, slate-gray juncos are a good example. And then there are two species of northern birds, the Lapland Longspur and the Snow Bunting. Their arrival signals the real beginning of winter. They return to their arctic tundra home in late March and early April.
Longspurs eat mostly wheat seeds and grasses, and the plumage of both male and female looks similar. Commonly found in the company of Snow Buntings, their song is a melodious warble. Snow Buntings look like large snowflakes from below. They travel in large flocks, often more than a hundred, and can be seen in the Rouge Valley along the rail corridor every winter. Their winter food is millet, cracked corn and, if they can find it, sunflower seeds. Snow Buntings can survive temperatures as low as -50°C. Their song is a musical high trilling. These white-breasted arctic voyagers nest farther north than any other land bird, in the upper reaches of Ellesmere Island and Greenland. True to their name, they burrow into the snow on cold nights for warmth.
Migrant waves of Golden-crowned Kinglets, Horned Larks, Brown Creepers, and Red-breasted Nuthatches also winter in southern Ontario and, along with Tree Sparrows, can often be spotted in the Rouge Valley. Evening Grosbeaks mostly hang around bird feeders, and another northern finch, the Common Redpoll, a sparrow-like bird with a bright red cap, has a reputation for surviving colder temperatures than any other songbird. There are about a dozen species of northern nesting birds wintering regularly in our area; winter irruptions can easily add another 20 species.
We also have some birds that don't migrate but stay with us through the cold season. Among them are the beloved Black-capped Chickadees, the brilliantly coloured Cardinals, the skittish Belted Kingfishers, and the marauding Gray Jays. The alluring Cardinals can readily be identified by their distinctive song, and their flashy colour makes them easy to spot. They also stand out for being among the few songbirds whose more plainly-clad females answer their whistling wooers with similar melodious airs. In close quarters, males raise their crests, crane their necks and sway back and forth as they sing softly to their mate. Later on, nest-bound hens whistle to their foraging spouses whenever more grub is needed. On the bird feeder, I have observed that the female always patiently waits until the male has finished feeding before it's her turn. Young Cardinals, recognizable by their dark (as opposed to red) beaks, sponge off their parents for several weeks after they learn to fly. But eventually, they leave and go off in search for their own space.
Chickadees are also known for their song, but as well for their lack of shyness. School kids on our winter walks in the Rouge love to hold out some seeds and have the birds land on their outstretched hands to pick up a morsel. On the other hand, the Belted Kingfisher doesn't appreciate humans close by, but is nevertheless cherished by birders and nature lovers alike for its wit and charm. How can we not be fascinated by a bird that dives into the water like a fighter jet to emerge with a minnow that it then beats into submission against a branch, flips it in the air and swallows it head-first?
Pigeon-sized Belted Kingfishers dig tunnels into muddy river embankments for nesting. Egg-laying occurs in mid-April and the incubation of the usual five to eight glossy white eggs lasts 22-24 days. The breeding pair share the task of nest-making. The hole in the embankment is usually a fair distance away from the fishing site, so the pair must defend both territories simultaneously. When the young birds hatch, they are naked and helpless. Until they are ready to leave the nest, they are tended by both parents who bring food to the nest and feed the hatchlings directly. After fledging, the parents teach the young birds the basics of fishing by dropping fish they have already caught into the water for the young to retrieve.
The Belted Kingfisher's ability to raise its spiky crest when relaxed and pull it down tightly when intimidated is only one of the endearing behaviours that give this bird its character. With its loud, harsh, rattly screams, it may not possess the sweet song or brilliant colours of a rare songbird, but the Belted Kingfisher more than makes up for this with its irresistible charm. I am always eagerly looking forward to their arrival in March.
Gray Jays are often called “camp robbers” because of their habit to brazenly snatch food from picnic tables. They also like to play tricks on people. A lot of them hang out in Algonquin Park. They are cousins of the Blue Jays, but slightly smaller, and a member of the crow family, live about eight years, and do not migrate. Their diet includes insects, berries, amphibians, small mammals, bird eggs, fungi and occasionally carrion. They are quick to learn that humans can be an excellent source of food, too. Whatever Gray Jays collect or “steal” they store in caches throughout the forest that last them through the winter. Gray Jays begin breeding in February and mated pairs need a territory of about 70 hectares. Unfortunately, these smart birds are declining too. In Algonquin Park there are now 60% fewer Gray Jays than there were in 1980.
A lot of the information about winter bird population and migration comes from the annual Christmas Bird Counts held across the country, coordinated by Bird Studies Canada and the National Audubon Society. The average number of species tallied in the Toronto area averages 79 - 89, but in “good” winters can be as high as 120. This winter will be remembered by many of the volunteer birders for this event as one of the stormiest, snowiest, windiest and coldest counts on record. Many counts between December 14 and January 5 were rescheduled because of severe weather conditions, and some were cancelled outright when it was considered unsafe to travel. But the birds were there, and the intrepid birders who counted them had many interesting sightings to make the effort worthwhile. You can find the results of the counts on the Audubon website.
I will be back with another Rouge Valley Nature Notes in the spring. Meanwhile, enjoy the season, look for birds, hug a tree, and have an invigorating hike in the always wondrous and beautiful Rouge Valley.
Sources: Nature Canada, Ontario Nature, Canadian Wildlife Federation, Bird Studies Canada, Wild City, and field notes.
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