Good trees for birds to replace hedges

In the next year or so, I'll be removing the conifers to the right and adding a fence. I feel awful, since a lot of birds, especially house sparrows, use it for nesting, but it's so unruly that I can't keep it. Plus I want to grow a border along the edge of the garden, and they've turned it into a desert under there. My aim is for this to be a net positive for the wildlife long term

So, I'd love to plant some trees when they come down to give some cracking nesting sites for the future. I don't want anything huge (the hedge is over 10 metres, something smaller than this would be perfect), and of course I'd like it to be something that looks good to appease the wife.

I'd love any suggestions! Cheers.