Is Plywood toxic for Bird Houses?

I have some plywood lying around and I was going to build a bird house because I like wild life and wood works so,
Anyway, I hear some types of wood are toxic and shouldnt be used for bird houses, is plywood nomally toxic?

Answer 

1) i have been building bird houses for 50 years and if the plywood has been laying around foe a while its ok to use,,,they build houses out of plywood,they build furniture out of plywood,they build lots of things out of plywood if it was dangerous they wouldn't use it,,, haven't had any dead birds in any of my houses,and they are used alot

2)  Nah. Any wood that would be toxic are most likely those treated with creosote(green or brown) mainly used on posts bottom halves so they don't rot as fast in the ground.Cedar shakes if fresh might be toxic because its natural oils in the woods keep moths out of chests thus saving wool from being moth eaten.
Other than that, plywood is OK, chipboard(not much good after a couple of rains), particleboard(not much good after a couple of rains), rangerboard(not much good after a couple of rains)-ranger also has formaldehyde in its makeup so not healthy to work with(for you). I believe it has been pulled from the market because of the formaldehyde. Rangerboard is just compressed cardboard.
Plywood is the best bet for longevity. Leave it unpainted on the inside. And mount it on the north side of a tree(so it gets some shade) otherwise it is same as an oven....you will have a couple of "friers" in there.
Don't make too air tight, or too small. because the bird will still build a round nest in there. Also have a front door and a back door(escape route should a predator bird be at the front door) and a "heat release" slot near the roof line. These birds are there for the spring summer. No winter heating required.

Also build a few of them. Birds are not solitary. They like company. That is why they fly around in "herds".
Growing bright colorful flowers in the garden nearby attracts bugs which feed the birds. And make sure you have a bird bath someplace. Even it it is just an old garbage can lid upside down with a bit of water in it from the sprinkler.
Plywood is the easiest to work with. Try avoiding using any other glue (if you do use glue during construction) than white carpenters glue. The others have chemicals in them. But if the bird house is big enough and airy enough, noxicity should not be a problem.Then again you could just leave them alone to pick out a tree or a bush where they would build their nest as they have since the dinosaurs.