Yellow-billed Loon - first-winter, Colorado River near Parker, La Paz Co., AZ. January 19th, 2011. Images taken using Canon Powershot A495 handheld through Swarovski HD telescope.
This bird was frequenting both sides of the AZ/CA state line on the Colorado River just north of Parker and was originally found by David Vander Plyum et al on January 15th. Susannah and I failed to find it on January 16th en route to the Salton Sea, but I tried again on January 19th and eventually found the bird off Riverside Drive about 3 miles north of the Blue Water Casino.
For my money, the most exciting of the loons with a unique jizz and well worth the drive (about 3 hours from Phoenix). Remarkably, this was my third Yellow-billed Loon in Arizona, the other two also coming from the Colorado River - one at Havasu City in Feb 2001 and one on Lake Havasu in Feb 2008.