Hawks ARE scavengers.
Hawks are opportunistic feeders and will scavenge if a chance presents itself. While most species prefer live prey, some species of hawk, such as the red-tailed hawk, are more likely to scavenge than others.
Hawks are solitary hunters that prowl during the day. With eyesight twice as good as a man's, hawks use their specially-adapted wings to make sharp turns while in a dive. They prefer to dive onto prey from a perch and will in fact choose habitats with numerous high perches over those with more available food. Unlike falcons which capture prey with their beaks, hawks catch prey in their large talons. They then carry their prey back to a perch to behead and consume. Small prey is swallowed whole, but with larger prey, they begin feeding on shoulders and ribs.
Scavenging hawks are not picky eaters, but when hunting, they choose small, defenseless prey. Smaller birds, rodents, amphibians and lizards are their most common marks. If hungry enough, larger hawks will be a little more ambitious. Capable of carrying up to three times their weight, hawks will hunt jackrabbits and small domesticated animals like cats. They are even known to pluck the koi out of koi ponds.