Went camping in the Uintah mountains of Utah for 8 nights. Many times we were visited by hummingbirds. They would stick their beak in the cold ashes outside the fire pit. The ashes were very fine, maybe from charcoal briquets. Apparently the ashes had something they liked or needed. Any ideas what that could be?
The ash from a wood fire, and charcoal briquettes are made of wood products, is mainly calcium in the form of carbonate or oxide depending on the temperature of combustion. It also has potassium in lesser concentration, but still a significant amount.
Minerals, most likely. Flower nectar, of course, is lacking in minerals (as well as protein), so hummingbirds need to get these from other sources. Mostly they eat insects for this, but they could look for minerals from other sources.
No links, but this is a thing that has been observed.
Nitpick: It appears that the range in question is known as the Uinta Mountains; a Utah county at the east end of this range is known as Uintah County.