Yellowstone National Park (Mammoth Hot Springs).
This morning was overcast and gray and the sky blended with the off-white terraces at Mammoth. Blue birds flashed through the drab sky like florescent blue meteorites.
A pair of killdeer were wading through the shallow warm water of the springs, searching for and eating small bugs floating on the water’s surface. The insects floated through run-off channels, like small canoes in a shallow stream.
As one killdeer was foraging and wading among the thermophiles, another would make the distinctive and far-carrying "kill-deer" call. Killdeer are graceful plovers.
The travertine terraces in Mammoth Hot Springs host a variety of thermophilic bacteria including the fascinating Cyanobacteria which uses photosynthesis by day and fermentation by night - as part of its metabolism.