The Black-capped Chickadee is one of three or four types of chickadee we have in Oregon. It is the one type I recall seeing in our area.

Chickadees are popular with just about everyone, including researchers, who find them fascinating for these reasons - "Their vocalizations, interactions with other species, social hierarchies, food caching, winter survival, and brain-neuron regeneration make them fascinating research subjects" Add to all this the remarkable ability to "see ultraviolet wavelengths, apparently detecting differences between males and females. In many species that mate for life and share nesting duties, male and female plumages look identical to our eyes."

(Above information from: http://www.birds.cornell.edu/page.aspx?pid=1859 )