Hey birders!

So over the past couple of weeks, we've spotted a pair of hawks hanging around our yard. Our neighbours believe that they've set up a nest in one of three yards by ours, but are not sure where. They haven't attacked the kids or anything (yet...), but Kerry found a chewed-up mouse in our backyard a couple of weekends ago. So the question is, what kind of bird is this? We think it's either a Cooper's hawk, or maybe a sharp-shinned hawk or a boring old red-tailed hawk. Does anyone out there know? Hopefully you'll be able to zoom a bit on the pictures if necessary.