How to Help
Luckily, there are are many ways for you to help bluebirds in the wild!
Feeders
Although bluebirds can usually find their own food, feeders can be very useful during bad weather, the colder months, and breeding season. Bluebirds will generally eat seeds and suet out of a bird feeder, but the best food you can provide for them is mealworms. Bluebirds will readily eat them themselves, or bring them to feed to their young. Supplying mealworms in a feeder is a bit trickier than other foods, but it's worth it. Read more about how to serve mealworms here.
Windows
Surprisingly, windows are one of the largest threats for all wild birds, including bluebirds. Running into a window can kill a bird instantly, or leave it stunned and susceptible to predators. Window crashes kill nearly a billion birds per year! The birds see the reflection of trees or sky in the window and will fly right into it, unaware of the solid barrier. Luckily, there are a few simple ways to lower the likelihood of birds crashing into your windows. First of all, break up the reflection -- whether it's with window decals or strips of tape, the bird is more likely to realize that it can't fly through if there are unusual shapes in the way. Another useful trick is to place bird feeders close to windows -- around 3 feet. That way, a bird flying off from the feeder can't get up to maximum speed if it's flying towards the window, so even if it does crash into it, fatalities are much less likely.
Nesting Boxes
Nesting boxes, when constructed properly, can be a huge help for bluebirds. With humans rapidly expanding into the wilderness, and European Starlings and House Sparrows taking many of their usual nesting sites, a nesting box helps provide a safe place to take shelter and raise young. The North American Bluebird Society website includes several useful blueprints and guides for building nesting boxes for bluebirds. If you purchase wood that's smooth on one side and rough on the other, remember to have the rough side facing in! This makes it easier for baby birds to climb out and greatly increases their chances of survival. Make sure to score a few grooves in the outside of the box, too, near the entrance hole, so the parents have somewhere to hang on. If the wood is smooth on both sides, score grooves inside the box so the chicks can climb out.
I made an Instructable about how to use the North American Bluebird Society diagrams to make your very own bluebird nesting box! It can be found here.
I made an Instructable about how to use the North American Bluebird Society diagrams to make your very own bluebird nesting box! It can be found here.