Marine iguanas enjoy the sunshine, unhindered by any real threat of predators. Photo / Jim Eagles Expand

Marine iguanas enjoy the sunshine, unhindered by any real threat of predators. Photo / Jim Eagles

The first thing I saw after wading ashore on to Espanola island, and negotiating the lines of sealions sleeping on the pure white sand, was an Espanola mockingbird.

Watching it fossick along the shoreline in search of food I felt as excited as Charles Darwin must have done when he arrived here in the Galapagos, off the coast of South America, in 1835.

A mockingbird mightn't be as spectacular as a swimming iguana, soaring albatross or breaching whale but it so happens it was the discovery that this archipelago has four distinct kinds of mockingbird - three of them unique to a single island - that started Darwin thinking about how that could have happened.

Then, to add to my excitement, I saw three different finches: a small black one flitting in the scrub, a small brown bird hiding in the leaves and two identical large black finches with powerful beaks foraging for insects in the sea lion droppings. There are, in fact, 13 varieties of finch in the Galapagos and Darwin took specimens of most back to England where their distinctively different beaks made them the poster birds for his theory on how species evolve in response to local conditions.

Next I found a couple of quirky little lava lizards sunbathing on the sand, much as a group of bikini-clad young women from our ship, La Pinta, were doing further down the beach. Presumably they were Espanola lava lizards but there are three further varieties in the archipelago.

Later, kayaking around an adjacent islet, I came across a couple of marine iguanas - the only iguanas which actually swim - drying off on the rocks. Once again, you guessed it, these were Espanola marine iguanas but there are five other varieties found elsewhere in Galapagos.

Of course there are species that occur right across the islands, like those Galapagos sea lions sleeping on the beach, four of which roused themselves enough to frolic with our kayaks when we went exploring, or the distinctive black and white Galapagos penguins - the only tropical penguins - that flashed past my eyes once when I was snorkelling but were easier to see preening themselves on the rocks.

And there are also species that are found around the world, like the magnificent humpback whales that played around La Pinta every day, or the frigate birds with their distinctive v-shaped tails that constantly soared overhead looking for the chance to steal food from other birds.

But most of the incredible array of creatures found here are endemic to the Galapagos and many are unique to just one of the islands.