Once threatened, bluebird populations are now starting to make a comeback.
The decline of bluebirds was mostly caused by the reduction of its habitat. Bluebirds prefer to nest in cavities of older trees. But more intensive farming practices, more use of metal fence posts, greater use of pesticides in orchards, and the sprawl of urban development have reduced the available habitat for bluebirds.
If that wasn't enough, an aggressive species of bird was introduced from Europe into the United States. European starlings displace bluebirds from their nesting sites.
The most effective way to restore bluebird populations is to provide adult bluebirds with good nesting conditions so they can successfully raise their young.
Building a bluebird nesting box is a fun project. Many designs are available. Some common features are: the use of 1-inch-thick wooden boards, holes at the top of the box for ventilation and at the bottom of the box for drainage, a 1½-inch diameter entrance hole in the front of the box, and a door that opens for monitoring the progress of the nest.
Keep the nesting sites at least 100 yards apart. A pair of boxes are often mounted at each site. Often a bluebird will nest in one box, and another bird, such as a house wren, tree swallow, or chickadee, will nest in the other.
Install your nest boxes in areas that provide open space, such as near open grasslands, pastures, orchards, hayfields, and along roadsides.
The ground below should have grass. Bluebirds will perch on fence posts or branches to look for insects in the grass. Once they locate an insect, they will swoop down to collect and eat it.
Bluebirds raise one or two broods from late April through early August. Nest boxes should be visited at least every seven days during this period. By checking on a regular basis, you can watch the progress of the birds as they raise their young.
Online resources:
North American Bluebird Society
