How would you model a Bird class? What issues arise when you try to add a Penguin or Ostrich? (LSP violation)

A common modeling mistake is to define Bird with a Fly() method and then derive Penguin and Ostrich from Bird. Penguins and ostriches are birds biologically but cannot satisfy a behavioral contract that requires flying. This can violate the Liskov Substitution Principle because code expecting any Bird to fly would fail for those subclasses. I would separate common bird identity from capabilities such as flying.