This is a tip my mom shared with me in regards to putting shedded hair to use:

In the springtime, when the mother birds are busy building their nests, you can set out any hair you've shed for them to use as nest material. After collecting the hair from your brushes or combs, just set it in the grass or on a windowsill where they'll be able to find it. The hair will make a birds nest a little softer for the babies. However, I would think that you should avoid having any harsh chemicals on the hair, which could hurt the birds or make them sick. To be safe, the hair should be cleaned a little and rinsed before it is tossed outside.

Now, I'm no expert on birds, so I don't know if there is any truth to this whatsoever. I think its worth trying though.  :)

Hmmm....
I've never done that with hair, but I have done it with bits of scrap alpaca fluff from washing a fleece.  My hair gets so tangled on my comb I think it would just get the bird's feet tangled up.  But I might try that some time.

In the summer, I usually dry my hair outside, so there are usually a few strands that I leave out for the birds.  I also put my yarn scraps out in the spring for nest building.  We have very colorful nests in our neighborhood!