The ability of migratory birds to know when to migrate is legendary, and largely real. Nobody knows how they do it.
My theory is rather outlandish. Almost all migratory birds can sense the Earth's magnetic field: that's how they navigate. So an event on the Sun creates changes in our magnetic field, and the slower particles in the solar wind create changes in the weather 24 to 48 hours later. No psychic power needed.
But of course, global warming will stop birds from migrating, so climate alarmists please hold your breath waiting.
Well, I’ll accept your theory.
They know