Why do you think any of those definitions fit the case of the falcons?

I took a look at “MW’s” web definition and it seems singularly lacking. Perhaps you should consider purchasing a real dictionary.

Cambridge is a bit better: https://dictionary.cambridge.org/us/dictionary/english/missi...

A common theme is that for something to be “missing,” it should not be where you expect it to be. But if your expectation is invalid, then it’s not “missing,” you simply have wrong expectations, which is the case with these falcons.

For example, I could say that there are a million falcons missing from my front yard right now. Do you think that’s a valid way to describe it?