Toronto Star Referrer

Feisty, colourful bird of prey has a superpower

M. L . B R E AM REACH M. L . BREAM AT WILDINTHECITY@ GMAIL.COM

Returning to my car after a visit to the Leslie Street Spit on a day so grey the sky seemed to have swallowed the lake, I looked up to see a small dark shape perched on a nearby power line. It was a bird about the size of a mourning dove or blue jay. I’d recently seen a few doves resting on this very wire, so perhaps that was a possibility. But a jay? In all my years of walking in and around Tommy Thompson Park at the spit I’d never seen a jay. I needed a closer look.

With my binoculars, I was able to see that my mystery bird was an American kestrel. I gave a little yelp of excitement and called my husband over to see.

“Look at this,” I said to Peter, handing him the field glasses. “It’s a kestrel. The smallest falcon in North America.”

I could hardly contain myself. The last time I’d seen a kestrel had been some years ago at Colonel Sam Smith Park on the city’s western waterfront. I knew there were members of this species to be found if you looked hard enough. Experienced birders have recorded the falcon formerly known as the sparrow hawk across Toronto, from Marie Curtis Park in the west to Rouge Hills in the east.

There’s no doubt, however, it’s becoming harder to see this feisty and extremely colourful bird of prey. Over the past 50 years, the kestrel population in North America has decreased by more than 50 per cent. Scientists haven’t settled on a single reason for this decline. Instead, they’ve suggested a variety of factors, ranging from climate change and increased predation by hawks to exposure to pesticides, a reduction in available food and loss of habitat, according to an article in the spring 2019 issue of Living Bird magazine.

The few times I’ve seen a kestrel in the wild, it’s been sitting on a wire or scrubby bit of bush, typical places to spot this little raptor. Kestrels prefer open habitat where they can survey their entire territory from a perch like a fence post. In rural areas, they seek grasslands and farms. In urban areas like ours, they’re most likely to be found in places without heavy tree cover or other dense foliage that will impede their hunting.

Despite their diminutive size — females weigh about 150 grams, or about the same as four or five light bulbs — kestrels are ferocious predators. In the18th century, the Swedish scientist Carl Linnaeus named this bird Falco sparverius. Their genus name, Falco, is Latin for falcon; their species name, sparverius, is Latin for “pertaining to sparrows,” alluding both to their small size and their predilection for hunting sparrows.

It would be a mistake, though, to think kestrels eat only sparrows. On the contrary, these “sit-andwait” predators hunt a wide variety of prey animals. In the summer, kestrels are especially fond of grasshoppers but also take caterpillars, dragonflies, beetles and moths.

In the winter, when invertebrate prey is scarce, kestrels turn to small mammals like voles and mice to keep themselves going. These little rodents don’t hibernate but spend the winter scurrying around, searching for hard-to-come-by food. As they run from place to place, they mark their territory with urine.

As it happens, urine absorbs ultraviolet light. And here’s where it gets cool. Birds, unlike humans, have a superpower: they can see ultraviolet light. For kestrels, the urine trails of voles and mice are as brightly lit as airport runways, leading the little raptors to their next meal.

Even with their superpower, life is tough in the wild for kestrels. Their small size puts them on the menu of many other much larger birds of prey. American crows, barn owls and a variety of hawks, including red-tails, sharp-shinned, Cooper’s and northern goshawks, all prey on kestrels.

This made me wonder whether there might be a connection between the scarcity of kestrels and the number of hawks around. Redtails, in particular, seem to be everywhere, all the time.

In the summer, when I’m having my morning coffee on my deck, I hear their high-pitched screams — a rising kkk-eeee-arr that descends near the end — as they hunt in pairs over our neighbourhood.

This winter, on nearly every one of our walks at the spit, Peter and I have observed red-tails hunting from the low branches of the park’s eastern cottonwoods. These big raptors perch patiently, almost immobile, their piercing yellow eyes scanning the scrub for their next meal. Pity the rat or rabbit, snake or squirrel — or kestrel — that should fall under their penetrating gaze.

While the worldwide population of red-tails is considered stable at two million or more, their numbers have been increasing throughout much of North America from the mid to late 20th century. They are now this continent’s most common hawk. Human impact on the landscape is thought to be at least partly responsible; development converts land from dense forest to more open spaces, giving these fearsome birds of prey more of the habitat they need to hunt.

Despite how common they are, I never tire of spotting a red-tail at the spit. Up close, they are shockingly huge. Females, like most birds of prey, are slightly bigger than males, tipping the scales at nearly one and a half kilos. Perched on a low branch, these birds stop traffic with their size and imperious attitude. Cyclists and pedestrians alike pause to pull out their phones to snap a photo.

It’s unlikely, though, that a little kestrel hunting on the spit would cause a stir. This time of year, only the voles and mice might know it was there.

CULTURE

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2023-01-28T08:00:00.0000000Z

2023-01-28T08:00:00.0000000Z

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