Red-tailed hawks are the most common hawks in the area, and in fact they're found throughout North America. They have adapted to almost every type of habitat, from deserts to forests to urban areas. In the wild, they can live to about 20 years of age.
These hawks were silently watching the morning unfold, but they have sharp, piercing calls. I always giggle (or cringe) when I hear the kree-aw sound of a red-tailed hawk on television regardless of what hawk or eagle they're picturing. It's true, the red-tailed hawk has a memorable call, but come on movie and TV industry, we know the same bird isn't making the same sound in all the landscapes we're supposed to think of as wild. (Okay, I'm getting off my soapbox now.)
Female red-tailed hawks generally weigh between 2-4 pounds, while males are about 25% smaller. This is called sexual dimorphism and is common in raptors (and ducks, insects, spiders, reptiles, amphibians, and many fish).
Red-tailed hawks usually hunt from perches, swooping down to prey on small mammals, particularly small rodents. They will also occasionally eat birds, reptiles, insects, and fish. It so happens that this diet overlaps a great deal with Great Horned Owls. The owls hunt at night (and often perch on the same tree!), while the hawks hunt during the day. During twilight the battle is on.
Here's a good shot of the front and back of the red-tailed hawks. They have many color variations, called morphs that are generally categorized into light, dark, and intermediate. The morphs may be due to age, regional characteristics, and of course, genes.