Thursday, February 26, 2009

What Are Barnacle Geese?

Barnacle geese are interesting creatures of medieval folklore, and although there is apparently an actual type of bird called a "barnacle goose," according to medieval folklore they literally grow on trees. When they are ripe, they fall from the tree, and if they hit the water they are fine, but if they hit the land, they die.

In The History and Topography of Ireland, Gerald of Wales* claims to have actually seen them:
I have myself seen many times with my own eyes more than a thousand of these small bird-like creatures hanging from a single log upon the sea shore.

Other accounts rely on other authorities, but Gerald says he saw them with his own two eyes "many times." Assuming he isn't lying (and since he has a lot more interesting creatures, why lie about this one?), are there any modern theories about what exactly Gerald was looking at to cause him to think these geese grow out of barnacles on trees?

*By the way, Wikipedia, in all its glory, refers to Gerald of Wales as "a contemporary English author." I wonder if they thought his last name was "of Wales?" Heck, since he was half-Welsh and half-Norman, he'd no doubt have taken that as a double insult.


  1. Gerald of Wales as a "contemporary" author -- did they specify *what* he was contemporary to? Inquiring minds and all that. Surely he was contemporary to those of his own time....

    What I always heard is that if you look at a log with actual marine barnacles on it -- especially the kind called "gooseneck" barnacles -- and their feathery feeding appendages are extended, they look a little like they might be some sort of odd, tiny, one-or-two-inch geese. If you don't know enough about their internal biology to know what you're actually looking at, it doesn't take too great a leap of the imagination to visualize them falling off the log and growing bigger, into *real* geese.

  2. I always assumed it was goose barnacles, yes. There's a delightful article I read somewhere about certain mediaeval theologians who liked to use the barnacle goose to try to convince Jews of the truth of the immaculate conception. Clearly, if they can reproduce themselves so innocently in such vast numbers, it is a miracle of God that he could easily have extended to one tiny human saviour.