The beautiful blue-and rust Western Bluebird is actually a small thrush. They swoop over open fields to catch insects. They can also be attracted to backyard feeders with mealworms.
The bills of Western Bluebirds are not equipped to dig their own nest holes, so the presence of cavities in trees or posts, old woodpecker holes or nest boxes are very important. When building or purchasing a nest box for a bluebird, make sure you have the correct entrance hole size; the diameter is different for the eastern bluebird.
You can read about Western Bluebird nest boxes at the Cornell Lab of Ornithology NestWatch site.