I think the bird stealing bread has multiple implications in the song. I think the protagonist of the song is primarily upset since he let his lover go "out from under his nose." So his old lover is the first bird stealing bread. He probably ignored her and so she found some new bread, aka, another lover who will give her more attention, which is probably what was lacking in the former relationship, but in this new latter one, her new lover probably doesn't love her the way the former could. Now he's mad at himself for letting her go, and now, she's not getting the true love she deserves from this new lover, because he doesn't really love her for what she is. So now her new lover is the other bird stealing bread "right from under her nose."
I think the bird stealing bread has multiple implications in the song. I think the protagonist of the song is primarily upset since he let his lover go "out from under his nose." So his old lover is the first bird stealing bread. He probably ignored her and so she found some new bread, aka, another lover who will give her more attention, which is probably what was lacking in the former relationship, but in this new latter one, her new lover probably doesn't love her the way the former could. Now he's mad at himself for letting her go, and now, she's not getting the true love she deserves from this new lover, because he doesn't really love her for what she is. So now her new lover is the other bird stealing bread "right from under her nose."
Sorry that was so long winded.