The Ruby-crowned Kinglet is a tiny, energetic songbird—among the smallest in North America at just 4 inches long—olive-gray overall with a bold white eye-ring, white wingbars, and, in males, a small red crown patch that's usually hidden and only flashed when the bird is excited or agitated. Found in coniferous forests across Canada and the western mountains for breeding, then wintering across much of the U.S. and Mexico, this restless bird is constantly flicking its wings while hopping through foliage in search of insects, spiders, and occasionally berries or seeds, and it's known for its surprisingly loud, complex, warbling song for such a small body.