There's something about this we really like. While at first glance we didn't think cardboard would be sturdy enough for a house, even one for birds, we remembered just how light birds are, and think that as long as this was in a covered spot, it'd be lovely.
We also like the fact that flat pack shipping and no need for glue or tape, not to mention a biodegradable material, all help make for a lighter environmental footprint, an especially good thing when talking about wildlife.
DIY Cardboard Birdhouse, available for $5 from The Curiosity Shoppe.

Sprout Side Table
Even sheltered from rain, I can't imagine this lasting very long - like people, birds also release certain...waste fluids on a regular basis. I'd hate to see a nest full of baby birds fall out when the floor gets too wet and splits open.
It says the cardboard is laminated...so, it's waterproof.
Also, shipping anything is a bad thing. This product makes no sense against a wooden birdhouse that can last for generations.
Like it or not, but don't call it a "green" option.
I'm just guessing here, but the cardboard could be "laminated" in wax, like the nurseries use to ship plants, and they stand up to heavy use, dirt, and water.
It would be cool just to have the plans, so I could cut it out on our school's laser cutter.
This is completely idiotic and should not be sold anymore.
I just bought one as a "thank you" card for a friend who loves birds. I end up spending that much on adorable cards at Papersource any way. I love it and think it is fabulous.