From Science Daily: Early bird catches more than just the worm.

Compared with early birds, late risers are more likely to be cuckolded, a group of international researchers has found. The study’s lead author said they found that early risers used that time to mate with birds not in their social pair. Melatonin-implanted birds did not sire as many birds and later cared for nestlings fathered by an early riser in their nest. Study results provide insight into the evolution of the body clock. [continue]