I think the raptors I see from my office are "Peregrine Falcon" and not hawks, mainly
because of their wings when they fly. Here is a nice description:
"The often-held image of the Peregrine as a symbol of wilderness diminishes when one sees this falcon breeding on metropolitan bridges and urban skyscrapers or watches tundra migrants on their neotropical nonbreeding grounds speeding along traffic-jammed boulevards at streetlight height in Rio de Janeiro, Brazil, or Buenos Aires, Argentina, chasing bats at sunset. Indeed, a Peregrine is always worth watching; humankind has long admired this species as nature’s perfect aerodynamic performer and as a strikingly beautiful bird."
Source: The Birds of North America Online (Needs subscription)