The Bird that was a Fish


Birds have feathers and fish have scales, right? So how could people have ever thought that a large black and white bird came from a crustacean or some strange form of fish? But, amazingly, just a few centuries ago in parts of Western Europe, many folks actually did.

In all fairness, when considering our forbearers’ limited scientific knowledge, bizarre notions were bound to arise. Superstitions, folklore, and hearsay are early attempts at making sense of the world, and often a lack of experience and understanding factored into the development of some off-the-wall ideas. This lack definitely led to some interesting beliefs regarding one particular bird—the barnacle goose.

Where are the Eggs?

Overall, folks throughout Europe were quite familiar with geese. But not so much with this particular species. Barnacle geese winter in the Scottish Hebrides and in some western areas of Ireland, but they do not breed at these sites. This means that onlookers there who saw the birds could never find any of their eggs. The reason, inconceivable to many people at the time, was that the birds were nesting during the summer within the Arctic regions of the North Atlantic.

Clearly, the barnacle geese, like all other forms of life, were reproducing. But if there were no eggs, how exactly were their offspring formed? This was the puzzle. And based on the evidence available at the time, the answer seemed obvious, even if quite unusual. The answer, as many thought centuries ago, must be related to something commonly found in the birds’ wintering areas: barnacles. Frequently spotted on driftwood and the like, these formations were thought to be the young geese, an explanation that today accounts for the bird’s name. Thus, by means of association, in appearance and location, the barnacle and the bird became causally connected in people’s minds.

Remarkably, even first-person reports supported this fallacious logic. In Giraldus Cambrensis’s twelfth-century account within Topographia Hiberniae, the royal clerk and clergyman notes, “… with my own eyes [I observed] more than a thousand minute embryos of birds of this species on the seashore, hanging from one piece of timber, covered with shells, and already formed” (1). Some variations of the story by other writers indicate that fruit, dropping off trees into the water, developed into the geese (2, 3). Either way, the notion that the barnacle goose was not really a bird persisted with the support of erroneous eye-witness accounts from Cambrensis and others. But the pervasiveness of this belief likely continued for a more convenient reason.

Fish on Friday, Fish for Lent

Wishful thinking was without doubt a critical component for these legends’ popularity. Why? Well, periods of fasting within Catholicism (such as Lent) forbid the consumption of meat, including fowl; however, fish were acceptable. So since many people believed the barnacle goose was not really a bird, eating it was deemed excusable. Doing so, in fact, offered a win-win situation. The goose was a tastier (and plumper) alternative to fish. Secondly, according to this widely held misconception about the bird’s status, consuming it posed no problem for maintaining religious dietary restrictions.

Obviously, other folks who knew better or at least found the barnacle-bird connection suspect could not let this issue rest. How to classify the barnacle goose became such a problem that eventually the Roman Catholic Church intervened. At the Fourth Council of the Lateran gathering in 1215, Pope Innocent III declared that the bird should not be consumed during Lent (4). Despite this papal ruling, misinformation about the barnacle goose’s origins still remained rampant for centuries. Only as explorers ventured north, documented the areas where the birds breed, and reported their findings did many people at last recognize the barnacle goose as a true bird (5).

Eventually, the wintering and breeding aspects of migration became clearer to scientists and laypeople. Looking further into more misunderstandings about migration next week, we can see that the barnacle goose story, quite remarkable from today’s perspective, was just one of many incredible fallacies.


  1. Cambrensis, G. Wright, T. (editor). Forester, T., and Colt, R. (translators). The Historical Works of Giraldus Cambrensis. London: George Bell & Sons, 1905. p. 36.
  2. Lee, H. Sea Fables Explained. London: William Clowes & Sons, Limited, 1883. pp. 98, 101–103.
  3. Heron-Allen, E. Barnacles in Nature and in Myth. London: Oxford University Press, 1928. pp. 10–25
  4. Ibid. p. 16.
  5. Ibid. p. xv of forward.

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