There are a lot of places close to Toronto where you can still find forest birds. In the Rouge Valley in Scarborough, for instance. Or in the Baker family sugar bush just north of Markham. Or in the Hart Lake, Boyd, or Kortright conservation areas.
But they don’t have enough forest room for breeding populations to survive. So their numbers are not sustainable without help. They remain in these areas because they can draw reinforcements from the Oak Ridges Moraine. It stretches for 160 kilometres from the Forks of the Credit at the Niagara Escarpment, to a little way northeast of Cobourg.
The moraine is a ridge of sand, silt, and gravel left by receding glaciers. On the surface are forests; beneath the surface lie huge aquifers that feed fresh water to more than 30 watercourses flowing south to Lake Ontario.
The more we fragment the landscape of the moraine through development, the more we shrink the deep forest, and the more we deny breeding space to the birds that are found there.
Could fragmentation reach the point that we’d no longer have forest birds south of Newmarket and Port Perry? I’m speaking of red shouldered hawks (already listed as a vulnerable species), barred owls, broad winged hawks, blue warblers, sharp-shinned hawks, golden-crowned kinglets, whip-poor-wills, long eared owls, purple finches, and red breasted nuthatches.
They’re important not only because we like to see them. Environment Canada keeps track of their numbers because they are an indicator of biodiversity.
If we so crisscrossed the moraine with roads, golf courses, and assorted developments that there were no deep forests left, even though there were lots of trees strung out in woodlots, conservation areas, and greenbelts, would that mean the end of forest birds on the moraine. And if the moraine were no longer a breeding reservoir for places farther south, would that mean the end of forest birds in the Rouge Valley, the Boyd, the Kortright, Hart Lake, and the Baker family sugar bush?
I put the question to Mike Cadman, a songbird biologist stationed in Guelph with the Canadian Wildlife Service of Environment Canada.
His response was guarded, as it should be from a research specialist. « There would be a real potential for a decline,’’ he said.
« I can’t say definitively how serious the situation would be, because this is at the leading edge of our knowledge.’’ But current research is suggesting very strongly that not just the size of a tract of forest is important, but so is the number of tracts in an area.
In layman’s language, that translates to me as: « We mess with the moraine at our peril.’’
The problem is that the moraine is managed in pieces, not as a whole. The Ontario Government has downloaded responsibility for planning to municipalities and regions. And, in an attempt to ensure that there is consistency in local planning decisions, it has issued an 18-page « Provincial Policy Statement’’ which sets out the principles upon which decisions are to be based.’’
However, the principles don’t deal with ecological systems; they deal with parts of systems, such as wetlands, waste management, farm operations, gravel pits, and fish habitat.
There is little attempt see the parts as a whole. Little effort to deal with Big Pictures. In the case of the Oak Ridges Moraine, there is no statement of principle that recognizes the moraine as an integrated unit. That sees each part as a strand in a far bigger web.
The Federation of Ontario Naturalists has urged Queen’s Park to issue policy guidelines for the whole of the moraine. « If the Oak Ridges Moraine is to be adequately protected, firmer provincial commitment is needed,’’ it says.
The regional councils of York, Peel, and Durham are going a step farther; they are seeking provincial approval to draft a policy statement for the moraine, which the province could then adopt.
Wish them luck. Everyone throughout the Greater Toronto Region will benefit if they succeed.