Nature Link: Native Birds

Here Come the Bluebirds
By Kevin Lang

    The Eastern Bluebird (Sialia sialis) has become one of the most popular birds to observe in the wild. Eastern Bluebirds range from the Rocky Mountains all the way east to the Atlantic Ocean. They thrive in open, grassy areas with little understory. Their diet consists mainly of insects but they also enjoy fruits and berries. Males are easily identified by their bright blue heads and backs, while females are more grayish in these areas. Both have red breasts and chins, which distinguishes them from their close relative the Mountain Bluebird (Sialia currucoides). 

    Unfortunately bluebird numbers began to decline in the 1950's and 60's. Reasons for this decline were due to the loss of habitat, severe winters, and increased competition for nesting sites with other bird species. Non-native species like the European Starling (Sturnus vulgaris) and the House Sparrow (Passer domesticus) use similar nesting sites and take over bluebird nesting cavities. To increase their numbers agencies like the North American Bluebird Society and local birders started to put up wooden boxes that the bluebirds could nest in. The reason for this is Eastern Bluebirds are known as second cavity nesters. They are unable to dig or scrap out areas for their nests, so they use what nature gives them. They search for dead, hollowed out trees and old, abandoned nests from different species of birds. Bluebirds took advantage of this and were quite successful for some time. Unfortunately the landscape began to change. Forests were extensively logged which decreased the amount of natural edge in the environment, native grasslands and meadows were converted to agricultural cropland, and naturally passive bluebirds were getting kicked out of their nests by exotic, more aggressive species like the European Starling and the House Sparrow. Bird counts across the nation were seeing a tremendous drop off in Eastern Bluebird numbers. A movement to help bluebird nesting areas began in the 1970's. People started installing bluebird nest boxes to provide nesting cavities for these birds.

    Would Eastern Bluebirds like the idea of living in a man-made wooden box? Experts were not sure if this solution would work, but it did. Slowly but surely bluebirds began to take up residence in these boxes. Competition for nest boxes by starlings and sparrows still occurs. Landowners need to monitor boxes to keep non-native birds from using nest boxes. 

    Jean Ellen duPont Shehan Sanctuary installed two bluebird trails comprising of 24 bluebird boxes. This spring and summer volunteers helped monitor bluebird boxes weekly. This past summer 19 Eastern Bluebirds fledged with a success rate of 70%! 

    If you are interested in becoming a bluebird monitor please contact Amy Bourque by calling (410) 745-9283 or via e-mail at abourque@audubon.org. You can also get involved by supporting clubs like the North American Bluebird Society or by simply putting up boxes by yourself. However there are guidelines for bluebird boxes to work effectively so contact your local Audubon facility, DNR office, or bird club to learn more.

Here is a typical box plan:

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Important Bird Areas

Important Bird Areas, or IBAs, are sites that provide essential habitat for one or more species of bird.  IBAs include sites for breeding, wintering and/or migrating birds.  To learn more about IBAs in Maryland and the District of Columbia, please visit our IBA page. 

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Photographs courtesy of Amy Bourque.
Some content courtesy of Nathalie Rubin.