I collect the yarn scraps from my knitting and every year we try to get them out early enough for the birds to nest with. I use mesh bags which I've saved from onions or other veggies. The D.B. usually hangs them up as she knows just where the birds look for nesting materials. This year we had enough yarns ends, between New York & NJ stashes of yarn ends for six little bags. Three are temporarily missing but will soon turn up. The one pictured is a present for Marsha's friend (and mine, too), Elaine.
This afternoon there was a pair of cardinals on the lawn so we're just in time, I think. I try to get some shiny yarns in the bags as the birds seem to be attracted to glittery things.