People such as colonial entrepreneur Edward Cargill (who had the 'castle' built in the 1870s) have long valued cliff-top views and the privacy they afford. Many seabirds also nest on cliffs – not only are they next to the sea and high enough to give a good take-off point, but they're also harder for predators to access, making eggs and chicks safer.

Fairy prions are small seabirds that feed mostly on crustaceans near the surface of the water. Although common in New Zealand's southern waters, they were thought to breed only on offshore islands where there are no rats or other introduced predators.

However in the 1990s a local conservationist found them nesting on ledges part way down the 70m high cliffs just south of Cargill's Castle. His surveys showed that there were breeding birds on ledges and in overhangs, safe from rats and disturbance from any other animals.

Forest & Bird's work with fairy prions

Dunedin's branch of Forest & Bird is working hard to make sure this colony survives by providing nest boxes for the prions, as well as making a predator-proof fence around steep land at the top of the cliff.

This will enlarge the area that prions and other seabirds can safely breed in. They have also set up speakers that broadcast the calls of other species of seabird, in the hope that this will attract new species to the newly-improved habitat.

For more information:

• Read a blog post about Forest & Bird's work with prions.
• Friends of the Prion Fence on Facebook
• Forest & Bird Dunedin branch