Sirius sat in his flat, contemplating what he was going to do for his birthday, when an owl flew into the room through the open window. He raised a brow, wondering who it could be from. He'd already received owls from Harry, and from Molly.
He pushed himself off the couch and stood up, walking over to the kitchen table, where the owl had perched its self on top of one of the chairs. He took the letter from the owl, noting that it wasn't even written on parchment, which could only mean one thing; the letter was from Cosette. He unfolded it, quickly reading it, before walking over to his desk and scratching out a reply.
Cosette,
Does this mean you were thinking about me? Not that I'm surprised. I'm flattered.
I suppose I should also be flattered that you remembered my birthday. Not to mention I'm amazed that you bothered to send an owl. Well, thank you very much for the birthday wishes.