Our budgie, Sunny—who's gotten her own press coverage—is pretty smart. She's figured out that a teapot full of hot green tea is a nice, toasty spot to get warm. On cold nights, whenever she sees a teapot on the table, she flies over and perches on the handle.
(Her cage is open most of the time, although her flight feathers are kept short enough to keep her from flying very far in the event she gets outside—we have a lot of cats in the neighborhood!)
"Mmm ... nice and warm."