Most wood is okay to use as long as you get it properly weathered.
I don't know what the perches are, but I imagine with some boiling or soaking, they would be perfectly fine. I know I used to see manzanita (with the bark on) for perches pretty often a decade or so back. Not sure what they use now.
I'd strongly encourage you to take a day trip to a local lake, river, canal, whatever, and go on a hike. Keep an eye out for deadwood, and take something home if it looks interesting.
Give it a good soaking, scrub it a few times with a brush, maybe even boil it.