I once heard that if you wanted to grow what birds ate then put up two posts with a wire between them and till the ground beneath the wire. The birds will plant it for you with their natural seed dispersal program.

Eddie, is that the reason I can't keep the weeds out of the grass under the clothesline? LOL

Coriander, check your local extension office to see if they have a list of bird friendly plants that do well in your area. I could make some suggestions but I'm not sure about their hardiness in your colder zone. Since this is going to be for children, watch out for things like poisonous plants, thorns, and plants that cause allergic reactions. And remember that birds need three things to be happy: food, shelter, and water. Provide these and you should have great success.

Good luck!
Sandy

You may want to look into perennial Sunflowers. These are small sunflowers that don't bloom until late summer/fall - are perennial (summers growth dies back, new growth comes up from bottom). It's food that finches love to nibble on. It's a messy rangy sort of plant though... and self-seeds all over. But I get quite a few birds munching on the tiny seed heads.

Coriander,

You might get some ideas on the Wildlife Forum posting - Berries for Birds.

Summer