Could this have been confirmation bias, or something else?

The dream and the brief inability to move sound compatible with a sleep-related experience such as sleep paralysis, though nobody can diagnose that from a short description. Vivid imagery and fear can happen around the transition between dreaming and waking, especially after a tense, stimulating night.

That doesn't prove what happened, but it gives a fairly ordinary explanation without needing to assume an outside presence. If episodes like this become frequent or interfere with sleep, talking with a healthcare professional would be reasonable.

Once fairy stories were on your mind, it would be easy for a strange dream, a tingly feeling, or an unusual flock of birds to feel connected. That's a normal way attention works, not a sign that the experience was made up.

Crow numbers can vary around a food source, too. One surprising morning doesn't tell you much on its own, even if it felt eerie at the time.

You don't have to settle on a supernatural explanation or dismiss the whole thing as meaningless. The experience can feel intense and still have ordinary ingredients: late-night media, anticipation, a vivid dream, and noticing details that might otherwise pass without much thought.

If you want to check your interpretation, write down what happened before searching for more stories, then note what repeats over several days. For now, taking a break from frightening material before bed and getting back to a familiar routine seems like a sensible move.