Geese Darken the Sky

Snow & Ross' Geese -- Sacramento National Wildlfe Refuge, CA
Canon EOS Rebel T5i, EF 100-400mm f/4.5-5.6L IS II USM, f/5, 1/1000s, ISO: 125

I've heard there used to be so many geese and ducks in the Central Valley that they would darken the sky.  That's easy to imagine at Sacramento National Wildlife Refuge.  If you're in the right place at the right time you might even experience it.