I know this was supposed to be a Spring type of project, but I just learned about this recently and Spring is just too far away for me to wait.
All you need is some scraps of yarn and a suet feeder station. I got this at Target for about $3.00.
Then you fill it with yarn scraps and little birds will take some and weave them into their little nests. It will make me giddy if I find a nest with some bright yarn woven in! I heard that it works, but I am not holding my breath since it's the end of October and the weather is getting nasty around here already.
I will leave this out for a couple of weeks and will put it back when Spring comes, but I had to share in case you want to give it a try too.