A pair of ornithologists from Western Illinois University spent 15 months observing a rare northern cardinal with gynandromorphism -- exhibiting both male and female characteristics.

Between December 2008 and March 2010, Brian D. Peer and Robert W. Motz made more than 40 total days of observations of a bilateral gynandromorph northern cardinal (Cardinalis cardinalis) in northwestern Illinois whose condition gives its plumage color a distinctive, down-the-middle split -- male red on one half and female brownish-grey on the other.

It turns out life may be a bit lonely, and devoid of music, for such birds. The researchers noted that their subject, observed primarily near a bird feeder, never paired up with another cardinal and it was never observed singing. On the plus side, perhaps, the unusual cardinal was not subjected to any unduly combative behavior from other cardinals.