There was once a hobbit, who was given a ring by his uncle. It was a rather beautiful ring, strangely fascinating in its way, golden, heavy, and surprisingly cold to the touch; the hobbit was disquieted by the gift, and decided to sell it.

/thread So off he went to the jewellers in the strip mall outside Hobbiton.

The jeweller stared at the ring wide-eyed.

There's no contradiction.

When I was a kid I knew the difference between blackberries and any other berry you might find in the hedges.

But my partner was told "berries in the hedges can poison you". And despite the exceptions like blackberries, that's true as a general rule. Similarly, "birds fly" is a general rule, despite the existence of ostriches and penguins.

You can expect to find exceptions to almost any real-life example of a general rule. But that doesn't mean "birds fly" is a lie: given a random bird, it's a safe bet that it flies.