What to do with a bird house full of sticks

My bluebird box was just vacated by a bluebird family and now (just a couple of days later), it is filled with twigs by a wren. No soft material in it yet. So how long should I wait before clearing out these twigs so that bluebirds or some other birds, with more serious intentions, can move in? Thanks.

One reason wrens use dummy nests is to keep other birds from using a nest box. Bluebirds usually take a two week vacation between their first and second broods and this is when chickadees and wrens may move in to a vacated bird house.

A male House Wren or Carolina Wren may lay claim to a nesting cavity by filling it with more than 400 small twigs. If the female likes what she sees, she will then take over, making the soft nest cup with grass, inner bark, hair, and feathers. Wrens will usually lay 2 broods in the nesting season from May to July.

The male wren builds several starter nests and the female is the one that chooses which she prefers. The other nests may be used by the male to raise a second brood with another female or remain in place to discourage other male wrens from nesting in the same territory.

The stick-filled cavity of the wren nest provides "stilts" for the nest cup which allows rainwater to collect in the bottom of the nesting cavity without endangering the eggs or young.

You can remove the sticks a wren has put in the box if you think it’s not being used. However if you remove the sticks and he puts them back in the box just leave them there to allow the wren to nest or remove the sticks and leave the box wide open to deter any bird from nesting.

If the bluebird comes back to a house that a wren now feels is his, the wren could destroy any eggs or young of a bird trying to use "his" box.

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• Cleaning & Placement of Wren Bird Houses http://bit.ly/KttSvT
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• 5 Tips to Attract Birds to Nest in your Bird Houses http://bit.ly/uWN7fE
• Common Backyard Bird Nest Identification http://bit.ly/GRg910
• When do birds begin nesting? http://bit.ly/GGuobs