Eastern Bluebirds

Mar 24, 2011

By Steve Blight

For many rural residents, the arrival of the Eastern Bluebird is one of the most welcome signs that spring has finally sprung. This cheery member of the thrush family normally arrives back in our area by about the last week of March. The earliest I have ever seen one in Ontario is on March 18.

Bluebirds are one of most easily recognized birds. The male’s deep blue back and head, chestnut-orange breast and white belly are unmistakable. The female looks like a slightly duller version of the male. It isn’t a large bird – at about 7 inches in length, bluebirds are significantly smaller than their cousin, the American Robin, which measures in at about 10 inches in length. In fact, it’s only a bit bigger than the house sparrow, which is about 6 inches long.

Bluebirds breed across eastern and central North America, from the Atlantic Provinces to south eastern Alberta and all the way south to Mexico and Central America. It prefers open habitat with short vegetation and scattered trees. In our area, pastures and orchards are ideal, as long as suitable nesting cavities are available. Although small numbers of bluebirds are recorded in southern Ontario during most winters, by far the bulk of “our” bluebirds spend the winter in the south eastern United States.

The history of changing bluebird populations over the past couple of centuries has been fascinating. Bluebirds undoubtedly benefited greatly when eastern forests were cleared to make way for European settlers and their crops and domestic animals. Prior to European settlement, bluebirds were likely confined to recently burned areas within forests and to natural prairies in southern and central Ontario. Once extensive farmland had been created, populations likely increased dramatically to fill these newly created preferred habitats.

Then along came the introduction and subsequent population explosions of European House Sparrows and European Starlings in the late 1800s and early 1900s. These aggressive newcomers out-competed bluebirds for natural cavities in trees and fence posts, leading to major declines in bluebird numbers. The next hit to bluebirds came with the arrival of intensive farming when hedgerows and other marginal farmland were routinely cleared to improve farm productivity, reducing available habitat for bluebirds. The increased used of pesticides since the end of the second world war has also been suggested as one of the factors contributing to the decline in the numbers of bluebirds and other songbirds. Finally, there were a number of harsh winters and late spring storms that had devastating impacts on adult bluebird across their North American range. By the early 1970s, populations had bottomed out and bluebirds had become worryingly scarce.

Since then, a combination of warmer winters and a huge growth of individuals and groups dedicated to putting up bluebird boxes across North America has led to a significant increase in blue bird numbers. In fact, Eastern Bluebirds are no longer listed as a species as risk at either the federal or provincial levels. Ontario’s bluebird lovers can take comfort knowing that the future of these handsome birds appears quite promising.

For those who have suitable open grassland habitat and would like to attract bluebirds to their property, the following link provides great plans for appropriately sized nest boxes. Download and follow the detailed nest box plans entitled “Tree Swallow, Eastern Bluebird and Great Crested Flycatcher”.

http://www.birds.cornell.edu/nestinginfo/nestboxref/construct

It’s important to pay close attention to the instructions on how to deter raccoons. These cute but abundant omnivores are a major hazard for nesting bluebirds. They can easily climb up to active nests and reach into unprotected nest boxes and destroy eggs, nestlings and even adults in their endless quest for food. 

Please feel free to report any observations to Lorraine Julien at This email address is being protected from spambots. You need JavaScript enabled to view it.  or Steve Blight at This email address is being protected from spambots. You need JavaScript enabled to view it.