Related Clues:
- Greek character
- Pi-sigma link
- Wonderland creature
- Christogram component, perhaps
- Pi's follower
- Thickhead
- Long-extinct bird
- Pythagorean character
- Extinct bird of Mauritius
- Bye-bye birdie?
- P, on a fraternity house
- It became extinct less than 100 years after its discovery
- Sigma neighbor
- Sigma follows it
- Christogram component, sometimes