I would suggest installing a nest box in your yard and installing a water feature. Bluebirds love water, especially shallow moving water. Also planting berry producing shrubs and trees will entice them to your yard in fall and winter. Providing food will in some instances….but I would start with the box. Then you could start feeding mealworms near the box during nesting season(if you have a successful nesting). This is how I started years ago. Here are my bluebirds at the bird bath.
Lexi
Virginia