The original sentence is mostly clear but can be improved for grammar and flow. A corrected version is:
Tropical birds have unique appearances and skills: shiny peacocks, tough shoebills, speedy cassowaries, and hummingbirds that can fly upside down and backwards.
Explanation:
- "unique looks" is better expressed as "unique appearances" for slightly more formal clarity.
- Adding a colon before listing the birds improves structure.
- Adding commas after each bird name clarifies the list.
- "backwards" is acceptable but some prefer "backward"; both are correct.
This version maintains the original meaning but improves grammar and readability.