The Galapagos Islands straddle the equator 600 miles west of Ecuador. There are five inhabited islands and many other smaller ones all of which are volcanic in origin and have been formed recently. The archipelago is well spread out with even some of the larger islands not visible from any of the others. Visitors travel to the islands on regular flights that take one and a half hours to cross the vast expanses of the Pacific Ocean. There are few other places in the world that are as much as 600 miles from any other land and the large distance from the mainland has helped in the creation of the unusual flora and fauna.
Underwater topography shows the origin and development of the archipelago. The islands are tips of volcanoes coalesced to form a platform at 400 metres beneath sea level, 2-3000 metres above the ocean floor. Each island is formed by a single volcano apart from Isabela which has six major volcanoes. All Galapagos’ volcanoes are smooth and rounded in a shield shape; their basalt lava flows are hot which allow the gases to escape and the lava to flow smoothly producing shield-shaped volcanoes. On the mainland volcanoes are shaped like elegant cones, indicative of more violent eruptions. Espanola in the south-east is the oldest island at about 5 million years old, Fernandina in the west is the youngest at about 0.7 million years.
The flora and fauna show close affinities with those of South and Central America, but the difficulties in crossing 600 miles of ocean account for the paucity of animal life. There are no amphibians, few reptiles and only nine land mammals: seven rodents and two bats. The islands have a great interest to ecologists because of the high percentage of endemic forms that live in the harsh conditions; of 700 species of higher plants, 40% are endemic. Isolation is the most important feature in the formation of new species. Colonisation has been essentially by accident and many species or potential colonisers have not made it (pollinating plants and insects). Invaders find new environments, few competitors, few predators and few food plants or insects.
On arrival at San Cristobal air terminal the tameness of the avifauna was immediately apparent as a YELLOW WARBLER and a DARWIN’S FINCH were feeding inside the terminal as I collected my ruck sack. My travels around Galapagos were aboard an eight berth ocean going bath tub called the Albatros. We boarded in the late evening to the accompaniment of BROWN PELICANS, BLUE-FOOTED BOOBIES and the ever present MAGNIFICENT FRIGATEBIRDS. We weighed anchor at 2.00 am and set off for Espanola some five hours away. The weather was, to say the least, decidedly variable and the Albatros cut through the waves with the grace and eloquence of a dead whale. When the engine failed, the boat began to wallow in the ocean swell. My stomach finally lost control and the rest of the night was spent bent over the side rails studying the krill that lit up as the boat surged past. To cheer me up, at 5.00am I glimpsed my first views of two SWALLOW-TAILED GULLS as they flew around the rigging and the navigation lights. These are the only nocturnal gulls in the world and look like a large Sabine’s Gull.
As it got light I made a dramatic recovery from my night time vigil, chuntering over the side; for the first bird I focused on was a WAVED ALBATROSS flying close to the boat. Several more of these albatrosses were seen as we anchored close to Espanola within view of the seabird colonies.
This island’s most important ornithological feature is a colony of 12000 pairs of WAVED ALBATROSS which is nearly the whole world population, with just a few pairs nesting on islands near to mainland South America. My visit in mid-January coincided with the two month period when all of the albatrosses depart to the Humbolt Current off Peru, returning to breed in mid-March. During our walk across the island, we were fortunate to see the single juvenile albatross that had not left. Stepping on to the island we were greeted by HOOD MOCKINGBIRD; a tame, inquisitive bird endemic to this small island and one of four mockingbird species to be found on Galapagos. With only four other land-birds to be seen on Espanola it was the seabird colonies that took centre stage. BLUE-FOOTED and MASKED BOOBIES in their thousands were sitting around, apparently in no hurry, as the breeding season could last all year if necessary in the consistent climatic conditions. RED-BILLED TROPICBIRDS were breeding here in small numbers and each time they flew by their sleek,
distinctive plumage caught the eye. Of the other seabirds SWALLOW-TAILED GULLS were to be found standing around in good numbers, BROWN NODDIES were scattered along the rocky shoreline and just for a change the ever-watching eyes-in-the-sky, were contributed by a colony of GREATER FRIGATEBIRDS.
We left Espanola in the early afternoon for a seven hour cruise to Santa Fe, an island with a safe overnight anchorage. Then, next day, a short early morning journey took us to South Plaza, a small, low, flat island formed by an uplifting of the sea bed rather than an eruption. Here with the introduced predators all having been eradicated, Land Iguanas have been reintroduced and are thriving. A cliff face, 20 metres high, runs the length of the island’s southern side. Much of the life of the island is concentrated around the cliff including sealions, Marine Iguanas and a host of
seabirds. AUDUBON’S SHEARWATERS are constantly in view either entering their nests or just sitting around on the water. With no natural predators they are much more visible on their breeding grounds here, being able to visit their nests, at will, without fear of harassment. The ‘blue-riband’ species, RED-BILLED TROPICBIRD nests on South Plaza and obligingly gives views as good as the Fulmars at Hunstanton Cliffs. They fly back and forth showing off their superb plumage to it’s best, with the long tail streamers continually being buffeted by the updraft.
The climate in Galapagos is unusually dry for the equator, with low rainfall, low humidity and relatively low air and water temperatures. Generally conditions are unpredictable and often very severe in the lowlands – this is responsible for so few species surviving. There is much variability of rainfall between years, so occasional drought years place strong natural selective pressures on plants and animals. The special mix of tropical and temperate environments allowing penguins and fur seals to live side by side with cacti and tortoises.
Like most islands, Espanola and South Plaza are very inhospitable with very little rainfall leaving a dry, arid landscape. There are exceptions to this and the next island we visited, Santa Cruz, has an upland area of lush, green, tropical vegetation. A few of the islands have volcanoes that break through the cloud base over the Pacific that is constantly around 300 metres and this high land consequently enjoys climatic conditions similar to the cloud forests on the mainland. Although not the capital of the Galapagos, Puerto Ayora on Santa Cruz is home to the Darwin Research Centre that is the base for all environmental research on and around the islands. They also offer their knowledge and assistance to the National Park Service and direct research in ways that may benefit the Park Service. A walk around the Darwin Centre looking at the Giant Tortoise breeding pens also produces the opportunity to see many land birds that are attracted to the drinking pools. It is possible to see up to eight of the thirteen species of DARWIN’S FINCH at these pools. All of the DARWIN’S FINCHES have drab brown, grey or black plumages and their names are little more exciting than their looks. At one pool I was able to see VEGETARIAN FINCH, CACTUS FINCH, LARGE TREE FINCH, SMALL GROUND FINCH and LARGE GROUND FINCH all drinking together; hardly electrifying but five ticks in a minute isn’t all bad. The whole archipelago has been designated a National Park with strict controls on the movement of the approximately 1000 tourists each week. The only free movement is on the five inhabited islands, including Santa Cruz, that have sizeable areas of farmland and many introduced predators that essentially exclude much of the natural flora and fauna from them. Many uninhabited islands also have introduced plants, insects and animals that have affected many of the islands’ natural environments in the 170 years since Charles Darwin’s visit in 1832. Much of the National Park Service’s time appears to be taken up by controlling the populations of introduced predators in the form of cats, rats, dogs and goats and rearing programs to ensure the survival of endangered reptiles.
Travelling further north-west through the archipelago, there were always new species to view on or near the coast line. LAVA GULL and LAVA HERON were regularly seen although in world terms their range is very restricted and their numbers are low. We reached another safe anchorage at a small island called Sombrero Chino late one afternoon. The beach was made of one inch pieces of white coral that proved to be very uncomfortable for a wet landing in bare feet. Two species that may have eluded me were to be found on this small island and fortunately both were close to where we anchored. GALAPAGOS PENGUIN breeds in the cold waters of the western islands of the archipelago, but a few non-breeders can be seen elsewhere. A group of six were to be found roosting in the sheltered waters between Sombrero Chino and the larger island of Santiago, only 100 metres away. The boat crew showed little interest in going to see them, but after a mutiny amongst the passengers had been organised, we were able to get very close views from a dingy. A pair of GALAPAGOS HAWKS from Santiago used this small island for peace and quiet to devour their food and dismantled a rat in full view of our boat as we ate our evening meal.
Sullivan Bay on Santiago is visited for its’ geological features; a vast lava field only put down 100 years ago which still has only a couple of pioneering plants taking hold on what is an otherwise barren but interesting landscape. Birds were virtually non-existant, with only AMERICAN OYSTERCATCHER and WANDERING TATTLER feeding on the shoreline and of course the FRIGATEBIRDS watching from the air. Off-shore of Sullivan bay, Bartholomew Island was hardly blessed with more birds, but did have a small party of Pacific Green Turtles on the beach.
This was an unusual sight, for although there are many turtles in these waters and many pairs are seen mating just off shore, normally they only haul themselves onto the beach to lay their eggs at night.
During journeys between the islands it was always worth watching off the front of the boat for dolphins, rays and sharks. Of the seabirds to be seen, GALAPAGOS, ELLIOT’S and MADEIRAN STORM-PETRELS were regular, AUDUBON’S SHEARWATER was common and I was fortunate to see half a dozen HAWAIIAN PETREL, which is now the most endangered species of bird to be found on the Galapagos. Only a hundred years ago, HAWAIIAN or DARK-RUMPED PETREL was not uncommon in Pacific waters, but due to human disturbance and introduced predators there is only a small population left on the Galapagos and an even smaller number on the Hawaiian Islands. The Park Service spend much time and effort trying to conserve the nesting colonies in the highlands and to an extent they have been able to stabilise the small population.
My last morning was spent walking from sea-level to the highlands on San Cristobal. As one climbs through the lowlands there is virtually a Darwin’s Finch in view all the time. Many of them are high up above the vegetation and flying with purpose and vigour, although you could hardly describe the LARGE GROUND-FINCHES or LARGE TREE-FINCHES as elegant. DARK-BILLED CUCKOO, GALAPAGOS DOVE and LARGE-BILLED FLYCATCHER put in an occasional appearance, then as you reach the wet highlands, VERMILLION FLYCATCHER and the famous WOODPECKER FINCH become common. From the roadside verge I flushed a PAINT-BILLED CRAKE which then watched me very warily from some dense vegetation, this bird is probably the most recent natural arrival on the Galapagos having first been recorded in 1953. Being a recent arrival it has not acquired the lack of fear that all of the other birds have.
My strongest memories of Galapagos will undoubtedly be the effortless FRIGATEBIRDS that were always on patrol and seemingly over see everything that goes on. I had recorded 55 species of bird in a week, including most, but not all of the endemics. Perhaps I might go back some day to see the Flightless Cormorant that unfortunately only frequents the most western islands.