bird table and unwanted crows

I recently erected a small bird house/tray which has an overhanding roof onto the garden fence. It turns out to be the local crow population who were cleverly eating the bird peanuts by landing on the bird house and manovering themselves to stick their large pecks into it and gobble. I've thought of putting a little wire around the 4 sides with a small hole for smaller birds, would anyone have any advice on how to deter them in favour of attracting the smaller guys? Thanks.

a single piece of string tied around the perimeter of the birdhouse (about half way up the support legs between the feeding base and the roof)

worked for me - failing that - a slingshot and small pebbles make for an entertaining way to enjoy your garden

If you put food out for the bird population then you have no say as to who will come and dine. All the birds are hungry and maybe even the rats and mice as well. This then attracts the local cats. It's a nice idea to feed the birds but seldom works the way you intended.

We have two bird tables and I regularly have to chase the hoovers (Seagulls) away and keep an eye on the wild cats who hover nearby. We recently have a Sparrow Hawk attacking the birds and have had to bring 2 pigeons to the vets because they were attacked. So as Swallow says it brings a certain amount of responsibility/worry with it, unfortunately.

I have a bird feeder in the garden, hanging from a long branch on a tree. Initially the crows used to land on the branch and managed to get the food. I lowered the feeder by about a foot with wire. That solved the problem.

thanks all for the suggestions. I'll try the trick with lowering a feeder net from the table.