Joan, did you read the article?
I'm no expert, but it wasn't an issue of the content of the fibers, but rather their ability to wrap around wings, legs, etc. and block circulation. It specifically mentioned hair.
Yes, I read it. Natural ones are in the suggested materials you *can* use:
"If you want to have nesting materials in your yard, we suggest
purchasing pre-made nesting material or use these natural alternatives.
Natural fibers ? such as cotton, wool, jute, and burlap ? make perfect
bird nesting materials.
Animal Hair: If you brush or clip your animals, save the fur! It makes a
wonderfully soft lining for bird nests.
I agree with the human hair, though (thinking of my own 18" long
tresses!). I have seen horse hair in nests around our place and I don't
know how one would stop them from using that.
My stitching buddy has four horses (well, three horses & a mule) and she fi
nds nests every year made primarily of horse hair and baling twine. The bi
rds comeback every year and they seem to have lots of babies. She puts the
embroidery fibers out, too, but cuts them in short enough lengths to not
get tangled and twisted.
Liz from Humbug