Back on December 29, Paul Hurtado was strolling through some woods along the Olentangy River here in Columbus when he encountered a most interesting beast (Ohio birders will probably remember last May's famous Kirtland's Warbler, which Paul also found here in Columbus). The female Northern Cardinal in the photo is a fully leucistic individual, which means that it has a genetic trait that blocks the production of melanin. Melanins are pigments that manifest themselves as dark colorations in feathers, but they also serve a whole host of other functions. David Sibley has done a thorough and scholarly job of detailing pigment abnormalities in birds RIGHT HERE.
This pink & white cardinal is just about as crazy looking as the yellow one in the preceding post, and thanks to Paul for brining it to light.