Always remove House Sparrow nests immediately. Have your bluebird boxes in place by mid-March when the bluebirds return from their winter migration and are looking for nesting sites. However, boxes may also be put up later in the nesting season. Bluebirds usually nest in late March or early April, depending on weather conditions. In southern states, where bluebirds reside year round, nesting may occur earlier.
Bluebirds usually have two broods per season, but three broods are possible.
Pine needles may be used. Bluebirds usually lay 4 to 5 light blue eggs, but may lay as many as 6 or 7. A small percentage of their eggs may be white. The incubation period for bluebird eggs is 12 to 14 days. Nestlings remain in the nest 18 to 21 days before they fledge.