This is the common Buteo of the southern farmland of Ontario, usually seen soaring in lazy circles overhead, or perched conspicuously on a big dead tree in the midst of a farm field.
Occasionally you may see one hovering over a field, then folding its wings to make a spectacular plunge upon some luckless mouse. Most enlightened farmers now encourage this bird as a prime aid in rodent control and leave its big stick nests strictly alone. Sometimes one will take up residence in the city, where its rodent and pigeon control may also be appreciated.
The ample wingspan and fan-shaped tail and soaring flight mark it as a Buteo.
The adults are easily identifies by their rufous-red tail and white underside of the wings in flight.
The immatures have dark brown tails with rather fine black bars, but their large size and white wing-linings also identify them.
The other large open country Buteo is the Rough-legged Hawk which has conspicuous black patches at the bend of the wing.
Both of them are larger than a crow.
The harsh guttural scream of the Red-tail is a good means of identification once learned.
Dr. J. Murray Speirs