Clara Oswald's students-- first years in this class, reading wizarding literature for the very first time-- were not often the sort to cheat on their essays or fight in her classroom. She wasn't known for giving miserable amounts of homework. She did, however, insist that they do the reading and that they pay attention in class. She showed them the same respect in turn. So when an owl bearing a scroll in its claws swooped in through the opening at the top of the tall windows and landed on her desk, she nodded to it courteously and gave it a snack, but did not otherwise interrupt her lecture on the second draft of Pride & Prejudice, the one that discussed Mr Darcy's more vicious reason for snobbery against the Bennett sisters: the second-rate wizarding academy they had attended.
The owl hooted at her, impatiently, and scuttled toward her on the desk. It had, she noted, eaten the candy bar but ignored the mouse. Surprising. She knew her species. That was a southern white-faced owl, not a popular messaging bird, but an impressive one, with magnificent facial feathers. She told it to wait until the end of class. It ruffled its wings and fluffed out its head feathers in a gesture she'd have interpreted as irritation in a human, but settled itself on the back of her chair without further complaint.
The class eventually filed out. Clara picked up the scroll and undid the ribbon. It was the Doctor's handwriting, she noted, fluid yet messy capital letters, ink smeared in places.
My dearest Clara it read, please do not be alarmed. Take a second look at the owl.
She turned. "What's this ab-- oh my stars and garters!"
The owl blurred and shifted. Clara's wand was in her hand before she knew it, and she raised it. Then the owl solidified: it was the Doctor, grinning at her exactly as if he'd been very clever indeed. She tucked her wand up her sleeve and willed her heart to beat slower.
"I did it!"
Clara stared at him. The month he'd spent refusing to come near her, over the summer holidays-- oh. Right. "Doctor--"
"It was trivial, in the end. Simple matter of following instructions."
He closed his eyes and shifted again, before her eyes, into an owl. He spread his wings at her and flapped. The wingbeats were eerily silent. He opened his mouth and hooted, and transformed back into the familiar figure of her friend. He brushed a bit of imagined lint from his black robes and rolled his shoulders.
"--strangest sensation," he said, apparently continuing on with something he'd said while in owl form. "An entirely different nervous system. Different vision system. Even hearing is transformed."
Clara closed her eyes, breathed herself into calmness, then opened them again.
"Are you planning on registering?"
Even as she asked, she knew the answer. The Doctor merely smiled.
"It'll be convenient. You now have two owls for use sending messages. And if I happen to go a bit off course while delivering your letter to your grandmother, well, who's to object?"
"You don't trust Fudge."
"As I am not an idiot, no, I do not trust Fudge. Or any of that lot of pudding-brains. I only trust Dumbledore, and that only when he's not making plans that include me. He'll kill that Potter boy before he's done."
Clara sighed. "I know. I know."
There was a noise from the hallway. The Doctor spun, tensed, and a moment later was the owl again. He hopped onto the back of her chair and commenced preening the feathers of his left wing. It was her next class, the third-years, on their way in with their dutifully-written scrolls on The Man of La Mancha.
Clara bent and brushed her lips over the feathery face of the owl. "Fly safely," she said. She opened the bottom of the window to the central quad and the crisp fall air, the scent of rain, the shout of students. The Doctor spread his wings, flapped, and was gone.