Tree Swallows displace Bluebirds...

 

Photo by Barry Wallace

While Eastern Bluebirds (Sialia sialis) often precede Tree Swallows (Tachycineta bicolor) to nesting boxes in the spring, they are very often displaced from nesting boxes by Tree Swallows.   Starlings and House Sparrows are also known to displace nesting bluebirds.   Specially designed birdboxes have resulted in a comeback by bluebirds, but Tree Swallows usually prevail in open woodlands, orchards and farmlands and parks with nesting boxes.   The photo above was taken at Cold Creek Conservation Area in King Township, north of Toronto, Ontario.

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Barry Wallace