Laudator Temporis Acti

Keith Thomas, Man and the Natural World (New York: Pantheon Books, 1983), p. 85 (notes omitted):

Finally, the old vernacular names for plants and animals were disliked because they were thought too coarse. Anyone who wants evidence of the way in which polite sensibilities have changed with the centuries need only consider the briskly anatomical nature of this now suppressed terminology, for in the seventeenth-century countryside there grew black maidenhair, naked ladies, pissabed (or shitabed), mares fart and priest's ballocks. In the herb garden could be found horse pistle and prick madam; while in the orchard the open arse (or medlar) was a popular fruit. Even the black beetle was twitch-ballock and the long-tailed titmouse bum-towel. Many of today's more fanciful flower names — lords and ladies, for example — are deliberate inventions of the nineteenth century, designed to obliterate some unacceptable indecency of the past; and some present-day survivors still conceal a grosser meaning given them by liberal shepherds in bygone days. The mid eighteenth century was a transitional period, when bowdlerization had begun, but not been completed. Even so genteel a figure as Robert Smith, official rat-catcher to George II's daughter, the Princess Amelia, could occasionally drop his guard, as when he refers in the cold print of his book on how to catch vermin (1768) to a bird called 'the large brown, white arse, ring-tailed hawk'. But then he lived in an age when Wittenham Clumps, those pleasant twin hills in Berkshire, were still known (after the local landowner's wife) as Mrs Dunch's buttocks.

Bum-towel as a bird name reminds me of Gargantua's search for the perfect torchecul (Rabelais, Gargantua and Pantagruel I.13, tr. M.A. Screech):

Then I wiped my bum on a hen, a cock, a pullet, on calf-skin, on the pelt of a hare, on a pigeon, a cormorant, a lawyer's bundle, a woollen hood, a night-cap and a stuffed decoy-bird.

But to conclude: I affirm and maintain that there is no bottom-wiper like a downy young goose, provided that you hold its head between your legs. Believe me on my honour, for you can feel in your bumhole a mirifical voluptuousness, as much from the softness of its down as from the temperate heat of the young goose which is readily communicated to the arse-gut and the rest of the intestines until it reaches the region of the heart and the brain. And do not believe that the blessedness of the heroes and demi-gods in the Elysian Fields lies in their nectar, asphodel or ambrosia, as these old women would maintain: in my opinion it consists in the fact that they wipe their bums on a young goose.