(UK, dialectal) The European green woodpecker, Picus viridis.
I remember the cry of the wood-peckers, or yaffils, as we call them in that country, going to roost in a pale autumnal evening […]. 1792, Charlotte Smith, Desmond, Broadview, published 2001, page 114:
“‘Punched that rotton strap,’ he goes on saying, ‘like a gret ol' yaffle punchin' a 'ollow log!’” 1924, Ford Madox Ford, Some Do Not… (Parade's End), Penguin, published 2012, page 119:
(intransitive) Of the green woodpecker: to make its distinctive cry.
Green woodpecker is not without options. Each year the builder comes to fix the house of the wooden roof. Green woodpecker watches then flies away, yaffling. 2005, Tim Kendall, Strange Land, page 13:
At the mention of yaffling—the cant for eating—Ewan felt a pang of hunger in his belly. 2017, Vanessa Kelly, Shana Galen, Anna Campbell, Kate Noble, A Grosvenor Square Christmas:
You're growing squab yaffling our food and then lazing in the hallway. 2019, Ellie Jacobs, Workhouse Waif: A Victorian Romance: