A black swan is rare not non-existent. The observation is credited to the second century Roman poet and satirist Juvenal:
“rara avis in terris nigroque simillima cygno” (”a rare bird in the lands and very much like a black swan”)
Juvenal never said black swans don’t exist. He simply wrote it would be unusual to see one in Europe. So he did not set up a test for falsifiability.
Europeans finally saw black swans in Australia in the 16th Century. At that point, black swans were no longer “rare”.
Europeans finally saw black swans in Australia in the 16th Century.
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The 16th century ran from 1500 to 1599.
Maybe you meant 17th century
This from Wikipedia: “The first known landing in Australia by Europeans was by Dutch navigator Willem Janszoon in 1606. Later that year, Spanish explorer Luís Vaz de Torres sailed through, and navigated, Torres Strait islands.”
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I am not going to Google “black swans”