Sunbathers

Not far from our house, there is an old, rusting, retired bridge. When I drove by on the new bridge this Sunday, I was surprised to see that several dozen Turkey Vultures (Cathartes aura) were assembled there. Some were on the ground under the bridge, and a few were gliding above in the clear blue sky and there were even Turkey Vultures seated on fence posts along the edge of the field.

But most of the big birds were seated along the railing of the bridge. It appeared to be a Sunday Sunbathing Party. With their broad wingspan, they were an impressive sight, even from a distance. Though they paused to look my way when I stopped the car and got out, they continued undisturbed while I snapped a few photos.

Turkey vultures are carrion eaters who locate their food by scent. According to Hughes (Birds of Ontario by Janice M. Hughes, ROM and McClelland & Stewart 2001) natural gas companies have exploited their keen sense of smell by introducing an attractive (to vultures) odorant into pipelines and identifying leaks by monitoring the locations of vultures circling overhead!

Turkey Vultures are one of the few birds experiencing a rise in population numbers. Their success is attributed to the warming climate, increases in deer populations, forest clearing and more roads with higher traffic volumes providing more roadkills.

Why here? Why now? I wondered. It’s thought that vultures and other large birds sunbathe in the early morning to warm up after a cool night. It had been a cool night, but when I spotted them, it was nearly noon. They just seemed to be enjoying a pleasant get-together of the local vulture crowd, maybe having a last visit before migrating. Too anthropomorphic? Maybe, but it won’t be long before they will be heading south. I wish them a safe journey.

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Roadkill

Recently, when we were exiting the highway and rounding the curve of the exit ramp, we were surprised by the sight of four large Turkey Vultures in the middle of the road in front of us. They were picking over the remains of a porcupine, nature’s clean-up crew in action. Three took flight as we approached, but the fourth held his ground, and I was able to take this photograph from where we had stopped at the side of the road.

The expansion of the road system has been good for Turkey Vultures, but not so good for pretty much any other member of the wild kingdom. One optimistic take on roadkill suggests that the numbers of dead animals littering the road is a good sign, an indicator that there are plenty of others living in the woods. Sadly, the real truth is that plenty of roadkills are only a sign of one thing: more roads.

Check out these two maps. The first shows the Southern Ontario road network in 1935, while the second shows the same region in 1995. The growth in our road network is glaringly obvious.

In fact, you are never more than 1.5 kilometres away from a road in Southern Ontario. Nor is it simply a matter of more roads. The quality of the roads has changed too. The graph below shows how, where once roads had mostly gravel or even dirt surfaces, the majority are now paved.

Paved roads mean cars travel faster. Cars travelling down a paved road are generally moving at a speed that is incomprehensible to an animal. An animal may dart across the road in front of an approaching car feeling safe in the knowledge that it can escape well before, say, an approaching fox could nab it. Or, in the case of a porcupine or skunk, safe in the knowledge that its natural defenses will protect it from all comers. In this they are sadly mistaken. Cars defy the rules of the natural world.

It’s not only the cars that kill animals. They are also impacted indirectly by road construction. Important factors include things like lose of habitat. There are also less obvious impacts. Road salt, for instance, is washed off roads and into waterways, where it disrupts the natural salinity of watersheds. The map below shows the salt burden born by roads. Southern Ontario is heavily impacted. Roadkill as a sign of a healthy population? Probably not.

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Fence Sitter

It’s not unusual to see a Turkey Vulture (Cathartes aura) drifting high overhead, its broad, 1.8 metre wide wings set in the distinctive ‘V’ that makes the bird so easy to identify. V is for Vulture. It’s less common to see them on the ground, but I recently spotted this individual resting on a fence post.

Turkey Vultures are a widespread species, with three subspecies ranging from Northern Ontario to Argentina. They haven’t been found in Ontario in large numbers until the last few decades. You are still most likely to view a Turkey Vulture in the south-west of the province, where the climate is a bit warmer. However, since the 1980s, the eastern Ontario population has more than doubled.

Turkey Vultures are almost exclusively scavengers and rarely kill live prey. It’s thought that one factor in their range expansion has been the relentless construction of new roads, which along with high volumes of speeding traffic, bring plentiful numbers of roadkill.

In rocky terrain, Turkey Vultures nest on cliff ledges or in crevices or caves. In more agricultural regions, they may use a hollow tree or an abandoned building. They prefer to nest in darkness, well hidden from predators and humans. The dark loft of an old, abandoned barn may thus provide good nesting habitat.

A migratory species, Turkey Vultures begin to move south in mid September, with the peak migration period running from the beginning to middle of October. Perhaps my fence sitter is resting up while contemplating the journey south.

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