Yaffle is a local or dialect English name for the green woodpecker. Readers familiar with the cult BBC children’s television series Bagpuss will know of Professor Yaffle, who is indeed a woodpecker. What brought it to mind was spotting one of these handsome birds in my garden, assiduously searching the edge of the lawn for ants. On the rare occasions one sees rather than hears a green woodpecker — with its green back, yellow rump and a crimson head that flashes in the sunlight as it turns its long bill — it seems too exotic to be a native British bird.
Mostly, the signal that one is nearby is its characteristic laughing call, which provoked this odd name for the bird. Other names for it, now rare, include rain bird (because its cry was said to bring wet weather), hickwall, wickwall, woodwall, and yuccle, though these have turned up in so many forms in various British dialects, such as eccle or ickwell, that their links are sometimes hard to detect. While we’re sure yaffle is imitative (the word could at one time also refer to the yelp of a dog), the other names are much harder to pin down; the Oxford English Dictionary hazards a guess that they, too, might be imitative, but they’re so old that they have been transformed out of recognition.
It has a number of other senses, derived from various English dialect words. It can be a description of somebody who is eating greedily, which is known in this sense in Royal Navy slang. And in the Newfoundland dialect it refers to a handful. This is from another English dialect word, spelled yafful in the English Dialect Dictionary.