"There are here many birds which are called Bernacae which nature produces in a manner contrary to nature and very wonderful. They are like marsh geese but smaller. They are produced from fir-timber tossed about at sea and are at first like geese upon it. Afterwards they hang down by their beaks as if from a sea-weed attached to the wood and are enclosed in shells that they may grow the more freely. Having thus in course of time been clothed with a strong covering of feathers they either fall into the water or seek their liberty in the air by flight. The embryo geese derive their growth and nutriment from the moisture of the wood or of the sea, in a secret and most marvellous manner. I have seen with my own eyes more than a thousand minute bodies of these birds hanging from one piece of timber on the shore enclosed in shells and already formed ... in no corner of the world have they been known to build a nest. Hence the bishops and clergy in some parts of Ireland are in the habit of partaking of these birds on fast days without scruple. But in doing so they are led into sin. For if anyone were to eat the leg of our first parent, although he (Adam) was not born of flesh, that person could not be adjudged innocent of eating flesh."
Jews in the Middle Ages were divided as to whether these barnacle geese should be killed as flesh or as fish. Pope Innocent III. took the view that they were flesh, for at the Lateran Council in 1215 he prohibited the eating of them during Lent. In 1277 Rabbi Izaak of Corbeil forbade them altogether to Jews, on the ground that they were neither fish nor flesh. Both Albertus Magnus and Roger Bacon derided the myth, but in general it seems to have been accepted with unquestioning faith. Sebastian Munster, in his _Cosmographia Universalis_ (1572), tells us that Pope Pius II. when on a visit to Scotland was most anxious to see these geese, but was told that they were to be found only in the Orkney Islands. Sebastian believed in them himself, for he wrote of them:--
"In Scotland there are trees which produce fruit conglomerated of leaves, and this fruit when in due time it falls into the water beneath it is endowed with new life and is converted into a living bird which they call the tree-goose.... Several old cosmographers, especially Saxo Grammaticus, mention the tree and it must not be regarded as fictitious as some new writers suppose."[84]