Birdhouses to attract swallows and deter sparrows

Credit: Carolyn Herriot

Has your birdhouse been overrun by sparrows? Carolyn shows you how you can get swallows to return

Over the years sparrows have overtaken all our bird boxes.

The house sparrow, like many pest birds, was introduced to North America in the mid-1800s. Since then, the house or English sparrow (not a true sparrow but a European finch), has become one of the most widespread and adaptive birds found on this continent. 
They are very aggressive in establishing territory and will soon dominate over other bird species in the garden.

I have seen sparrows throw swallow eggs out their nest in their determination to takeover. I want the swallows to return, and the only way to do this is to exclude the sparrows from the box. To do this we have attached a piece of wood to all our birdhouses, with an opening that keeps sparrows out and only allows swallows and smaller birds to enter.