Posts Tagged ‘bird population decline’


Once upon a time, when I used to work in an office in downtown Toronto and commute in from our rural home, I saw a Great Blue Heron (Ardea herodias) standing in a stream I passed over on my morning drive. When I got to work, I told the young woman who sat beside me that I’d seen a Great Blue Heron. Being a city girl through and through, she asked “What’s a Great Blue Heron?” I described the bird as best I could, a tall bird about 4 feet tall, grey-blue, long, pointy beak…. She didn’t believe me. She thought I was pulling her leg, that there are no such big birds in Ontario. I have to admit, she had grounds for thinking I might be teasing her, but in this case, my story was true. I had to get someone else to corroborate my facts.


Over the summer, I’ve seen herons regularly. It’s not unusual to spot one in our little river when I cross the bridge on the way to the main road. They’re shy birds. When I stop the car to try for a photo, they often fly away down the river and disappear into the greenery. Herons fly with deep, slow wing-beats, their long necks retracted into an S and their legs trailing out behind them.


There’s a bit of a pool by the bridge that attracts fishermen, and I think the herons are drawn to the spot for the same reason. Herons hunt for fish by standing very still in the water, sometimes wading in on their long legs up to their bellies, and waiting for a fish or some other tasty morsel to swim by. Then, with a rapid forward thrust of their bill, they catch their prey.


Foraging for food in this manner is a solitary pursuit. However, when herons raise a family, they get together in colonies. It seems a bit unlikely, but these large, long-legged birds build nests in the tops of trees, usually near wetlands or water. An average colony has about 35 nests, although some colonies may exceed 150 nests.


Colonies are quite stable, and may exist for up to 50 years, but 9 years is about the average heronry lifespan. A heronry is fairly easy to spot as the nests are large. They are made of interwoven sticks and lined with smaller twigs and leaves. I know of two heron colonies in the area, but both are well back from the road, and its not clear if either or both are still in use.


When I went out for groceries yesterday, I spotted 3 herons. Two were foraging in the waters of a bay along the edge of the St. Lawrence. A third was standing in a small wetland close to the roadside.


These regular heron sightings give me the impression that the heron population is in good shape, doing fine. This just goes to show how wrong such impressions, based on limited evidence, can be. In fact, the Atlas of the Breeding Birds of Ontario 2001-2005, based on extensive surveys of breeding birds, found that heron populations, like those of many birds, are in decline. There was a significant 37% decline province-wide in evidence of breeding from the same survey completed 20 years earlier. The cause of the decline is not understood. A decrease in amphibian species such as the Green Frog (an important dietary item for herons) over the last 10 years might be a contributing factor.


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