I've been involved with corncrakes for many years. (I'm tempted to say "Some of my best friends are ..." - but no, most of them are better singers!). I'm afraid the numbers are so low now that Mrs Beeton's recipe is unlikely to be used again. It actually disappeared (the recipe, I mean) in later editions of her book - hardly surprisingly.

Mind you, it's not so long ago that corncrakes were so common in Ireland that their incessant nocturnal calling drove people to taking drastic measures to shut them up!