Very large for a hummingbird; size alone separates from many other species. Males and females similar: even gray below, greenish back, brown rump, and large dark tail with prominent white corners. Also note white eyebrow and short mustache stripe. Males have a bright blue throat patch, but it is difficult to see unless the light hits it just right. Most similar to female Rivoli's Hummingbird, but note more even gray underparts (less speckled), more obvious white eyebrow, shorter bill, and larger white corners on tail. Common in Mexico; limited range in U.S. Found in canyons and mountains with mixed pine-oak forests. Visits hummingbird feeders.