Log Bird Feeder - 23 DIY Birdfeeders That Will Fill Your Garden With Birds (my note: I haven't looked at all of these, but at least one is a terrible idea. The window birdfeeder -- birds could fly into the glass and hurt themselves.
Just withoit the top.How to make a stone birdhouse (or fairy house) for a garden outdoors. Has link to free instructions. Great tips on sealer, glue, roofing choices, etc. One pinner suggested using PVC pipe for the house, and a funnel for the roof.