How to keep cat from raiding songbird eggs

Sorry it's taken me a few days to get back here, but glad to read all the responses and ideas. For now, we've wrapped the trunks in cardboard and string up to about the height we think the cat would bother to jump. Hope it holds through the rain and wet long enough to hatch the baby birds and get them flying.

I don't think we're doing the birds a great service though because they've built their nests lower this year. We kept the cat away from them last year and I think they expect us to do it again this year.

We have one cat. She's fixed and keeps current on all her shots. She's locked inside our shop building every night and during bad weather. She stays in her yard or in my kitchen window sill. We feel fortunate to have this cat even though we didn't choose her. She chose us about 5 years ago when someone dropped her in the ditch across from our house. We've never been cat lovers, but this one has earned her weight in gold keeping the many field mice at a reasonable level.

Thanks again everyone for the good ideas and the funny pics. This homesteading forum is the best!