As Urban habitat spreads it wings and expands it boundaries, so must man expect to find nature creating it's own niche within those ever growing cities. One of the most adaptable creatures in cities are birds, and of those the crow may be the most able to conform to urban living. Highly intelligent, with sophisticated social structures, the crow has no problem with having human neighbors. Ken Roblee is a Senior Wildlife Biologist for the NY DEC." They're very social, they use sentinels for warning the flock of approaching predators or humans, so they do very well because they are intelligent."
Crows and their cousins in the Corvid family, including Ravens and Jays, are in rare company on an intelligence scale.They are great mimics and can learn human speech. They are also known tool users, which puts them alongside only humans and primates in that regard. Mark Carrara is a Wildlife Biologist for The U.S. Dept. of Agriculture." Examples of that are where they're using a stick to dig out insects out of a tree cavity or something like that, so they do learn, they have a certain ability to learn, and use tools, which makes them from an anthropomorphic perspective, from a human perspective, that gives them a certain level of intelligence. "
For the most part urban crows go almost unnoticed. During the warmer months crows form smaller groups, but the colder months bring on a unique behavior. In the winter,the birds roost together in large flocks.Their numbers can reach in the tens of thousands, with some flocks counted at over sixty thousand ! Winter roosting is a natural part of crow biology, but what is unusual is their choice of cities as their roosting sites. Roblee offers an explanation."Possibly the light conditions in the city help them see predators approaching the roost, possibly cities are just warmer than just being out in other places in the landscape, the buildings can provide some wind protection, so cities seem to be now an area that can be selected for that winter roost site."
The crows are usually widely dispersed in smaller groups during the day, but sunset beckons the birds to gather, and these smaller groups travel to different staging locations, socializing there before eventually moving on, says Carrara." The last hour or half hour before sunset, what you'll see are these larger flocks of maybe a thousand or two, will sort of hopscotch their way into the city until they get to the final roosting site and all the flocks coming from different directions will join up together, and it is certainly an amazing sight to see."
A number of cities across NY and the country are experiencing issues with the enormous roosts, and most are trying to deal with them in a non-lethal manner. Carrara explains. "Pyrotechnics, loud noises, distress calls, spotlights, those are some of the tools and techniques that we would employ."
Depending on your perspective,the congregation of so many birds may be either a Hitchcock inspired nightmare or a spectacular display of nature's wonder. Says Carrara." You can have a hundred thousand crows in the city, but if you're not getting complaints, then maybe it's a pretty neat phenomena to have that many birds in your city. " Roblee concludes." They have an exceptional bird brain, that's why they're so successful."