Crows...

A *lot* of crows. A *murder* of crows, in fact. And this is only showing the sky in one direction, they were everywhere. Makes me wonder about passenger pidgeons (now extinct) - they were estimated to pass in flocks at a rate of 400,000 per *minute*! Billions of birds, leaving a layer of guano everywhere. Snapping branches off forests of trees when they landed. Blocking the sun for hours at a time. All this only 150 years ago. And extinct for > 100 years now.