Common, my foot. How many trips have I made looking for birds before I saw this one? Dozens? It may be "common", but it wasn't easy to see. This Common Yellowthroat (Geothlypis trichas) was flitting about in the rushes at the viewing platform along the auto-tour of the Merced National Wildlife Refuge. And I mean "flitting" in the most active sense of the word.
Their numbers have decreased by about a third over the last few decades, probably from wetlands habitat loss.