Have you ever given any thought of trying to provide nesting hummingbirds with a source of nesting material? I must admit while I have placed pieces of cotton in a wire suet feeder in the spring hoping it might be used by nesting birds, I never considered the possibility the white fibers might be used by a ruby-throated hummingbird. However, three events have caused me to change my mind.
Several years ago, I presented a hummingbird program to a garden club in southwest Georgia that met in the home of one of its members. While I was setting up my projector and screen, the host asked me if I ever heard of a hummingbird using cotton to build a nest. I told her although I had not, I could see how hummingbirds might incorporate cotton in a nest.
She then went on the explain that she had seen a female hummer collect cotton in her backyard. It seems she planted a cotton seed in a pot that sat near her house. The seed germinated and grew into a healthy plant festooned with balls of cotton. Since the plant looked attractive, she left it in pot throughout the winter.
The following spring while she was standing in her living room, looking out across her patio a female hummingbird flew down, plucked some cotton fibers from a cotton ball, and flew up to a nearby tree. The bird repeated this behavior several times. Although she never actually saw the bird using the cotton to build a nest, she surmised that is what the little bird was doing. 
I was reminded of this homeowner’s experience last week when I received an email from a man relating that he had witnessed a female hummingbird collect a bit of cotton from a suet feeder filled with cotton batting. This prompted him to search for a nest. Remarkably, his efforts paid off and he discovered a hummingbird nest close by.
Earlier this week I mentioned this event to a cousin. He was so intrigued by the story he went out and bought a wire suet feeder, filled it with cotton, and hung it out near his home. Unbelievably before the sun set he spotted a female hummer pulling strands of cotton from the feeder. Now he is looking for a nest.
With this kind of success, perhaps this is something we should all try. Even though a hummingbird might not avail itself of the cotton we offer, chances are other nesting birds will.
I have tried this some years ago, but no success. However, I wonder if this use of cotton would be the same as using dryer lint. I have read that you do not want to do this as the lint gets wet, and the babies are on wet and soggy bedding. Also, this would be hard for Mama to keep clean and could cause disease in the nest. Don’t recommend using this.
Martha,
You make some good points. It seems to me it would always be better to use natural fibers instead of synthetic materials.
I have a long-haired cat who’s fur is very fine and fluffy. When I groom him I take the fluff and hang it in suet feeder for birds to use.
Angie,
My daughter gave me a small bag of husky hair. I put in out and it was gone in a couple of days. Did the birds use the cat hair you provided them?
I have read that 100% cotton is good not lint fabric. I’ve read dryer lint is not advisable. Mine is hanging above the humming bird feeder and is being used with no problem. We used 100% cotton balls and hung above the humming bird feeder. It works just fine.
You are correct. We don’t need to put out dryer lint for hummers.