Migratory Patterns of the Unladen Swallow

Dr Maturin walked into the Entomological Society's meeting as the Reverend Mr Lamb began his paper on Certain Non-Descript Beetles found on the Shore at Pringle-juxta-Mare in the Year 1799. He sat down at the back and listened closely for a while; but presently the gentleman strayed from his theme (as everyone had known he would) and began to harangue the gathering on the hibernation of swallows; for he had found a new prop for his theory - not only did they fly in ever-decreasing circles, conglobulate in a mass and plunge to the bottoms of quiet ponds, but they also took refuge in the shafts of tin-mines, 'of Cornish tin-mines, gentlemen!'

(Patrick O'Brian, HMS Surprise)