Various species of birds prefer birdhouses of certain sizes. Of course, you will want to make the entrance hole large enough for the type of bird you wish to nest in it. The hole needs to be ONLY that size since larger holes invite predators (birds, squirrels, etc.) to invade the box, either killing the chicks or taking over the box and evicting the previous residents.

      Here's a handy table to use when building birdhous es. Double check the bird house plans you are using to make sure all measurements are in order. Then settle back and enjoy bird watching in your backyard.