This is funny. I've tried to make pigeons come into my terrace to feed them and allow them to nest with no success at all. Yet other people struggle to keep them out of their balconies :D
This year I found an egg again. I threw it away.
(that's how I learned about the magpie situation, was away long enough to have an entire laying-hatching sequence after leaving when freshly sterilized, I suspect they gave up early, magpie discovered and took the abandoned eggs, remembered the spot and came back to the chicks after the next breeding attempt - pure speculation but the schedule would just fit my absence)
There are all kinds of small and big birds that visit our balcony, especially in what passes for winter these days.
Seed-heavy diets, even if formulated for pigeons, are very fatty and may not make them feel great after eating. And bread is basically junk food for birds! So if you try a more nutritious blend of food made for them specifically, they may really enjoy it and come back for more.
Plus I imagine gulls won’t bother with their tiny food.