Analysis of potential sightings in Scotland's National Nature Reserves:
- Cliffs: Yes, especially in areas like St Kilda, known for its high cliffs.
- Seabirds: Yes, reserves like St Kilda are famous for large seabird colonies.
- Penguins: No, penguins are not native to Scotland; they are found in the Southern Hemisphere.
- Underwater caves: Yes, St Kilda is mentioned as having amazing underwater caves.
- Wildlife: Yes, reserves protect a wide range of wildlife, as stated in the text.
- Bluebells: Yes, Loch Lomond is mentioned as having woods full of bluebells in spring.
- Deer: Yes, Loch Lomond is mentioned as a place where you might see deer.
- Swans: Yes, the Insh Marshes are mentioned as having flocks of swans in winter.
- Feldmice: Yes, St Kilda is mentioned as having unique species of feldmice.
- Parrots: No, parrots are not native to Scotland.
Conclusion: Based on the text, you can potentially see cliffs, seabirds, underwater caves, wildlife, bluebells, deer, swans, and feldmice in Scotland's National Nature Reserves.