Roshe Knit Jacquard

The letter, written by Ottawa resident Orrin Clayton, complained that the crows scared away songbirds in the park, that they might boost the risk of avian flu to those living in the area, and that they produce a cacophony of "intolerable" cawing.

and falcons to scare them away.

The gatherings at Ottawa's Nike Roshe Run Flyknit Sail White String

and ears are available to watch for predators or even ward them off.

"I've watched them mob things like owls or hawks," Beck said.

However, some in the neighbourhood are less than thrilled about the eerie phenomenon, grumbling that the birds leave a big mess on the ground after they flock to a tree.

An open letter written to a local city councillor in May called on police and fire officials to try to disrupt the crows' roosting pattern.

While a murder of crows can be as small as a few birds, Chatham, Ont., is another community where much larger numbers have been known to congregate during the winter months.

The city has taken a number of measures to combat the problem, including setting up a crow control hotline and hiring a private company that flies hawks Nike Roshe One Retro Womens

"It's a little weird," said one nearby resident.

Hundreds of thousands of Roshe Knit Jacquard the birds arrive each year and remain in the area roughly until March.

It's like something out of an Alfred Hitchcock movie an enormous number of crows have been descending on an Ottawa neighbourhood each evening for the past several winters.

"They have a variety of sounds and they appear to be talking to each other. They also seem rather playful I've watched them doing little somersaults and little bonding routines where they'll fly around each other," he said, adding that they tend to huddle together for warmth on cold nights.

Beck described them as social animals with long memories who, in this case, may be looking for safety in numbers. The larger the murder of crows, the more eyes Nike Roshe Run Flyknit Black/Dark Grey/White

Coronation Park begin in the afternoon and swell as the sun goes down. More than 20,000 of the birds dot the sky and darken treetops in the park on some nights.

Thousands of crows gather at Ottawa