Sing a song of sixpence
A pocket full of rye
Four and twenty blackbirds
Baked in a pie
When the pie was opened
The birds began to sing
Was that not a tasty dish
To set before a king?
- The Only True Mother Goose, 18331
Humans are absolutely nuts. When you hear of singing blackbirds baked into a pie, it's easy to think that this is a joke, a metaphor, a silly children's rhyme... and it may be all of those things. But also, back in the 1500s, it may have been a bit of a fad for rich people to hide live birds in pies, which would fly out and surprise the guests when the crust was cut.
It is uncertain where the practice started, but it may well have been inspired by the character Trimalchio in Petronius' play Satyricon (c. 1 AD), in which the newly wealthy Trimalchio puts on a crass but opulent feast including a roast boar containing live thrushes and live birds in fake eggs.
The real-life implementation of live birds "cooked" into a pie appears to have been the brainstorm of Giovanne de Rosselli, the author of the 1517 cookbook Opera noua chiamata Epulario, reprinted in English in 1598 under the title Epulario, or The Italian Banquet. This book contained recipes from the fairly basic to the extraordinary, including a peacock cooked and then re-clothed in its original skin, feathers and all, with instruction in how to jazz it up further with gold leaf and an open flame coming from its mouth. The live bird pie recipe was the tenth recipe, sandwiched unexpectedly between "Fish Pies" and "To make the crust of Pie or Tart of Pigeons, Pullets, or Kid":
To make Pies that the Birds may be aliue in them, and flie out when it is cut vp.
Make the coffin of a great pie or pastry, in the bottome thereof make a hole as big as your fist, or bigger if you will, let the sides of the coffin bee somwhat higher then ordinary pies, which done put it full of flower and bake it, and being baked, open the hole in the bottome, and take out the flower. Then having a pie of the bigness of the hole in the bottome of the coffin aforesaid, you shal put it into the coffin, withall put into the said coffin round about the aforesaid pie as many small live birds as the empty coffin will hold, besides the pie aforesaid. And this is to be at such time as you send the pie to the table, and set before the guests: where uncovering or cutting up the lid of the great pie, all the birds will flie out, which is to delight and pleasure shew to the company. And because they shall not bee altogether mocked, you shall cut open the small pie, and in this sort you may make many others, the like you may do with a tart.2.
For those of you who do not want to untangle the archaic spelling, it instructs you to bake an extra-large, empty pie crust, which is accomplished by filling the pie with loose flour and then emptying the flour out through a hole in the bottom once is it fully baked. This pie is then filled with live birds, which will fly out when the pie is cut. Also a real pie is hidden in the bottom of the large pie, so as to not disappoint the hungry guests; this pie is filled with a number of tarts.
How often this type of pie was actually constructed is up for debate, but it is part of a Renaissance fad of "subtleties" (often spelled sotiltes or solteties to make them sound more quaint, or referred to by the related French term entremets). These were artistic dishes usually on the order of fancy marzipan creations, but of course, limited only by budget and imagination. Robert May, in his 1660 book The Accomplisht Cook (Project Gutenberg), recounts a fantabulous dinner to be staged on festival days, with an entire landscape laid out with a battle scene, the centerpieces of which were two large pies, one filled with live birds, and the other with live frogs. The frogs were there to scare the ladies, and the birds to fly towards the lit candles and by their flapping put them out, thus throwing the guests into disarray.3
Given the historical evidence we might suppose that this trick has been tried at least twice, and probably a few times more. However, I doubt that this was the common practice on "Festival Times, as Twelfth-day, &c." as May indicates, and given that live birds, ready to take flight, are neither quiet nor toilet trained, I am dubious that this was ever the common practice some culinary historians like to suggest it was.
1. Note that this is not the original form of the rhyme, with the original refering to 'naughty boys' rather than blackbirds; whatever the point of this song is, it is probably not simply mocking the dinning habits of kings.
2. This text was copy and pasted from The Foods of England Project, as it is surprisingly hard to find a scan of the original text in English.
3. You may also see references to John Nott, cook to the Duke of Bolton, who published a book in 1723 (The Cooks and Confectioners Dictionary; Or, The Accomplish'd Housewifes Companion), in which he includes a section called 'divertisements' which is essentially a retelling of May's account.