Birds need access to a good food supply, water and the right nesting place.  A birds size will determine the kind of bird house you will need.  Birds want a home just large enough to hold their nests with an entry hole just big enough for their bodies.  They will pass by any house that doesn't fit their needs.  Its also important to place their house at a proper height above ground.  We provide a choice of entry hole sizes in our birdhouses to fit these needs.  Check out our handy Houses & Dimensions Chart for more information.