This is an excerpt from Le Viandier de Taillevent
(France, ca. 1380 - James Prescott, trans.)
The original source can be found at
James Prescott's website
Gannets. Cooked like the stork. (BN manuscript, p. 13.)
Recipes with similar titles:
Connates (Forme of Cury)
28 - Canudos (A Treatise of Portuguese Cuisine from the 15th Century)