Our baggage includes about buckets containing a dozen fledging Bulwer's Petrels which landed on board the Rapture last night; Beth plans to put them into sheltered rock crevices from where they will try their first flights again.

Once on shore, we put on our quarantine outfits - new clothing, shoes, and hats frozen for 48 hours to lessen the probability of bringing on board alien species of plants and insects. The island is part of the Hawaiian Islands National Wildlife Refuge, managed by the U.S. Fish and Wildlife Service; a special access permit is required for landing on the island. The Refuge was created in 1909 to protect the seabirds from poachers gathering bird feathers.

Beth and Gordon tell us that the native plants and birds are relatively intact on Nihoa, but there are lots of alien insects on the islands, primarily carried by humans to the islands, before strict rules for what can be worn or brought on the island were adopted in 1990. Both scientists are worried about the effects of these alien species on the plant and animal life of the island. Gordon points out that these island environments are very limited and fragile, and species so limited in number may be just a toehold away from extinction.

As we begin our hike to East Palm Valley we spot a rare millerbird-a small endangered warbler. As we proceed, Beth warns us to watch where we step as there are baby noddy on the ground, as well as burrows where baby shearwaters and petrels are hidden . Also, if we get too close, a nesting parent sitting on an egg or a chick, it might be scared off, and the egg or chick would get fried in the intense heat of the sun.

There is more greenery on the ground than is apparent from the sea-bunch grass, ohai and 'ilima - three native species. As we make our way over steep rocky ground, there are birds everywhere, flying overhead, perching on stones and low shrubs, some guarding their eggs or chicks. We see a chick emerging from an eggshell, as well as several dead seabirds in various states of decay.

There is no flat land on Nihoa everything slopes down to the south. Gordon and Beth point out agricultural terraces where native Hawaiians who inhabited the island centuries ago planted crops, perhaps sweet potatoes, to sustain themselves. Later we walk past a cave shelter, with a low wall across the front. Then another wall expertly built, still intact after all the weathering of centuries.

The archaeological remains on this remarkable island are a testament to the human ability to survive, as well as a reminder that sometimes things go wrong and human life is no longer possible.

While Gordon was talking about an alien scale feeding on the leaves of a loulu palm found only on Nihoa, a ladybug alighted on my hand. 'Aulani asked if it was a native; Gordon says no, it probably flew here from the main Hawaiian islands. How does it fit in? Gordon says it feeds on other aliens like aphids, scales and white flies.

Back down at the landing for our zodiac ride back to the Rapture, we eat lunch in the shade of cliffs. Three endangered monk seals lull beneath us, sunning themselves on the rocky shore. Beth carefully places the fledgling petrels we brought ashore onto a sheltered ledge. When the zodiac pulls up to the landing site, we depart.