Eminent naturalist and broadcaster Sir David Attenborough was caught out when he slipped up in identifying the song of a common British bird on live radio.
Sir David, whose TV shows have introduced millions of people to a vast array of wildlife around the world, admitted during an interview on BBC Radio 4's Today programme that he was "pretty poor" at recognising the birdsong of his own nation's countryside.
And he immediately proved that he was not being falsely modest by wrongly identifying the chaffinch as the bird whose chirps have often been described as sounding like the phrase "a little bit of bread and no cheese".
Bird-watchers immediately took to Twitter to point out that the distinctive song was in fact that of the yellowhammer.
And the confusion was compounded later when Today presenter Sarah Montague said that listeners had contacted the studio to say that the bird involved was either the chiffchaff or the yellowhammer.
Sir David's mistake came as he was discussing the Radio 4 series Tweet of the Day, which broadcasts the song of a native bird species for 90 seconds at 5.58am each morning.
"There is something attractive about hearing birdsong early in the morning," said Sir David. "Amid all these electronic sounds with which we are submerged by the end of the day, it's nice to start with a bit of nature."
Asked if he was good at identifying birds from their song, Sir David replied: " It's not that easy is it, learning birdsong? I'm really pretty poor at it, but a really good ornithologist of course can pick up birds by song long before they see them.
"I'm pretty good on the cuckoo, and I'm OK on owls, but there are all these sort of little whistly things which, if you are not very careful you get confused by, which is why in the books I was brought up on we had to put them all in words.
"A chaffinch for example was 'a little-bit-of-bread-and-no-cheese'. I'm quite good on that, but the cuckoo is my main forte."
Twitter user Robin Bisson created the hashtag #birdfail, as he wrote: "Did Attenborough just say chaffinches say alittlebitofbreadandnocheeeese? Think he means a yellowhammer!"
And Robin Usher wrote: "Did Attenborough get it wrong this am - 'a little bit of bread and no cheese' is the song of a yellowhammer, not a chaffinch."