Over several days' stationary observations at the same location at about 6200' in the Sierra Nevada (Nevada Co, very close to the border with Placer Co) I've heard/seen a single Ruby-crowned Kinglet.
Despite being a long time birder, without an ornithology background there are many gaping holes in my knowledge of bird populations. Based on my geographical locations in CA and on the southeastern US coast, I think of Ruby-crowned Kinglets as ubiquitous wintering birds and I recognize how they look, sound and behave as they forage. That's the extent of my knowledge.
Seeing/hearing only one Ruby-crowned over several days has sparked my curiosity. I looked up their range and found breeding range in the Sierra Nevada.
Now I wonder whether this lone bird is part of fall migration or not. Do "we" know much about how many and at what elevation these birds breed here? Do we know if the breeding population here are residents or if they, too, are migrants from elsewhere, whether far or near?
