Plants from Bird Seeds - are they edible for us as newly grown plants?

Probably a BONKERS question really - We have a Birdhouse which is flush against the housewall.  There are various planters underneath the Birdhouse, where the birds are eating some of the seed and bird food that we've put out, we were getting lots of 'unknown' plantlets - from the bird seed! Bearing in mind that it is now something of 'a new thing' to grow salad leaves, etc., and eat them very small - I was wondering whether it's possible for us to eat these little plants? I've now put a stop to this happening part of the way across our wall as we've put up a Shelf or 'wooden floor' which sits underneath the Bird House. It's worked out very well really - we had one family of 5 fledgling Yellow Tits & Mum & Dad all stood on this 'wooden floor', as the parents were tucking into a long container full of the fat strands that I'd put into the round vertical netting containers! It was AMAZING! The baby birds were trying out their flying skills by flying to our windowsill, having a wee  rest and then on to the 'wooden floor' for their Dinner!