Sometimes it takes putting food on a tray close to the bluebird feeder before the bluebirds catch on. It takes two to five days for female to complete nest. Females build the nest alone. Males will carry nesting material during courtship. Nests are light and airy, consisting of fine grass or pine needles, hair and maybe a few feathers, with a small cup shape in the center.
Possible parasites are blowfly larvae which can seriously weaken nestlings.
Diatomaceous Earth can be placed under the nest. This will cause the larvae to sustain cuts which help to dehydrate their bodies. Old material may be partially removed by bluebirds. It is best to clean out old nests for the birds. Bluebirds may come and go during several weeks before completing one nest.