Reconsider attracting birds to a garden that you know has cats roaming in it.

I have cats and birds, but I provide lots of thick shrubs and small fruit trees, along with big shrub roses and herbs to give the birds some 'cover'.

Cats like catmint, which will grow very well by squashes and melons. Along with radishes, catmint is supposed to bring in beneficial pollinators and help discourage 'bad' bugs. The kitties will probably enjoy it, too.

If you don't want the cats too silly, don't break the catmint. Once the branches break, the cats can get a bit carried away and actually kill the plant.

My cats also like pathways through the garden. They make them, themselves, often between the rose bushes and the herbs I have growing in front of the, to discourage the deer. Any cool, shady spot is fun for kitty, too :)

Oh, and there are lists of toxic plants for cats, dogs and horses on the Internet. I'd consult that, too!