Linking the northern shoulder of South America to the southern end of the Caribbean Archipelago lies the twin island nation of Trinidad and Tobago. This is a prime location for the enjoyment of the natural world, for observing and studying the bewildering variety of plants and animals collectively known as biodiversity.
Nowhere is this biodiversity more striking than in the tropics, especially so on the continental mass of South America where eons of warm, wet climate and sea level fluctuations created the conditions which led to the evolution of the increasingly specialized and varied life forms typical of the region.
Trinidad, only ten kilometers from the Venezuelan mainland, shares many of the biological characteristics of its huge neighbour. Tobago, a further forty kilometers to the North east, is typical of the palm-fringed paradise of the tourist brochures with white sand beaches and clear blue seas. But like its sister island it enjoys a rich and varied wildlife: biodiversity, if you will, with a Caribbean flavour, full of sound, colour ---and surprises.
This richness is further enhanced by the varied topography of the islands which creates several distinct habitats and ecosystems, each supporting a different assemblage of plants and animals. A range of hills rising to almost a thousand meters borders the north coast of Trinidad. Lesser ranges cross the centre of the island and the south coast. These are the most heavily wooded areas and provide habitat for many of the larger animals. The unique Trinidad piping guan or pawi, a highly endangered species, inhabits the forests of the Northern range. The montane forest gives way to lowland forest on the flat, deciduous forest in the drier areas and mangrove forest along the coastal wetland. Where soil conditions do not support tree growth, natural savannahs occur as in the Aripo Savannahs. These are home to a distinctive flora interspersed between islands of moriche palms. From the mountains, streams and rivers flow to the coast forming swamps and marshes. Here migrating birds find a place to rest and feed while on the offshore islands oceanic birds congregate to breed.
In Tobago the central ridge supports forests less dense than Trinidad’s but still rich in wildlife including several species which do not occur in Trinidad. The cocrico, or rufous-vented chacacalaca, is one of these and is the national bird of Tobago. A few like the ocellated gecko have been found nowhere else in the world. Indeed, together, with an area of slightly more than five thousand square kilometers, Trinidad and Tobago have an exceptionally rich biodiversity, --the richest in the Caribbean.
The liveliest, noisiest and most colourful of the creatures are the birds and none more so than those which feed on fruit and nectar. These include tanagers, hummingbirds and honeycreepers. The names of many of the hummingbirds reflect their iridescent splendor: The white-chested emerald, blue-chinned sapphire, the ruby-topaz.. As if they were not conspicuous enough, many species show off their bright plumage in a dance, congregating in groups to vie for attention from the females. A modest show is given by the little hermit hummingbird. Despite his name he is quite sociable and performs for the females with much tail-bobbing and preening.
Far more accomplished dancers are the manakins. The golden-headed manakin prefers to perform in the relative privacy of the forest canopy. His cousin the white-bearded manakin dances nearer the forest floor. He performs in an area known as a lek. This is a collection of several small clearings which act as individual dancing platforms for the male birds. He will spend as much as ninety percent of his waking hours at this avian ballroom. The dance is series of hops, buzzes and snaps and can involve as many as 70 birds, each one trying to outdo the other to gain the favour of the female.
The blue-backed manakins in Tobago offer a show of sound and colour as well as dance. The dance is preceded by a loud call, actually a duet. This is followed by a strange knocking sound, with two to four males participating. As excitement builds the birds drop onto a special horizontal branch where the dance escalates.
With a female in attendance the tempo increases to a truly spectacular performance involving a variety of sounds and an elaborate choreography that includes cart-wheeling, leaping and twirling and generally showing-off outrageously.
The discerning female judges the dance carefully and makes her selection. She eventually goes off on her own to tend her nest, and rear her chicks with no help from her dancing male.
The dance of the blue-backed manakins and their erie calls brighten the dark recesses of the Tobago. We are lucky to have them as these forests were devastated by Hurricane Flora in 1963. Only recently have they recovered. Another Tobago resident similarly affected by Flora was the white-tailed sabrewing hummingbird. For several years after the hurricane it was thought not to have survived but although still a rare sighting it is now making a comeback.
At night the songs of the forest and the marsh come largely from the male frogs as they serenade the females. Theirs is indeed a brave chorous for advertising ones presence has its dangers. These range from owls to bats to snakes and even spiders. The frog captured by this wolf spider is bigger than the spider itself.
While the daylight hours are dominated by birds the nighttime belongs to the bats.. The Tamana cave on the northern slope of Mount Tamana in central Trinidad is the Mecca for bats on the island. An estimated half a million of them inhabit this cave. Their tenancy and the nutrients they bring in via their feces dominate the cave ecosystem. Their sheer numbers create heat and carbon dioxide levels which make breathing difficult for those who venture there and the walls are plastered with giant cockroaches. On the floor amid the insects live some of the largest frogs known to Trinidad. Several species of bats dwell together in this underground colony, each with its own complex social structure. Here a phyllostomus male is seen guarding its harem.
At nightfall the bats exit their subterranean roost in search of food. As the light fades they pour out of the cave’s mouth. Despite their huge numbers, their speed and their closeness to each other, a sophisticated communication and navigation system prevents the collisions that seem almost inevitable as they leave to fan out over the countryside. In the course of the night they will, while feeding, perform the vital functions of pollination, insect control and seed distribution.
There are caves in the Northern Range as well which, apart from the many insects attracted to their moist, dark interiors, offer another unique spectacle. In them live the oil birds or guacharos. As the bats do, they forage at night despite the fact they feed exclusively on fruit. Unlike most birds they have a well developed sense of smell which helps them locate fruiting trees, especially palms. They swallow the fruit whole and regurgitate the seed later. The floor of the cave is littered with these regurgitated seeds, all germinating hopefully but doomed by the lack of light. In the complete darkness of the cave they rely on echo location, which, unlike the sonar used by the bats, can be heard as a series of clicks. The oilbirds are so named because their diet of palm fruit leads to their chicks having a very high fat content. The Amerindians who originally populated Trinidad and the early settlers would harvest oil bird chicks, separate the oil and use it for cooking and in lamps.
At the higher altitudes of Trinidad’s Northern Range, often shrouded in cloud, we find forests that have adapted to the heavier rainfall and cooler temperatures. The trees are festooned with mosses and other epiphytes, constantly dripping with moisture.
This is the home of the beautiful golden tree frog, a species that is specially adapted to live within the giant bromeliads that grow at these altitudes. The bromeliad serves as the frog’s entire universe. It lives and reproduces in the pools of water found at the heart of the plant. Its flattened profile permits it to move easily between the interlocking leaves. The golden tree frog is found nowhere else on earth other than the bromeliads in the moist forests of Trinidad’s highest peaks.
There is another species that is unique to the upper reaches of Trinidad’s Northern Range. The luminous lizard is so named because when originally discovered it was thought to be luminous and in the dark recesses that it inhabits, the bright spots on its side may well have appeared to glow.
The Northern Range’s heavy rainfall is channeled into the valleys and folds on the mountainsides to form the headwaters of streams and waterfalls surrounded by communities of plants suited to such moist conditions. These streams form the tributaries of the larger rivers flowing from the foothills and into the adjoining plain on the south side of the range or, from the northern slopes down into the sea. The pools along these watercourses are richly populated. The Trinidad Guppy carries the name of one of Trinidad’s early eminent naturalists and is found in aquariums throughout the world. The guppies share the stream with tetras, cichlids and other creatures like the galap, and the Trinidad otter.
Some of the south-flowing rivers flow eventually into wetlands. The largest of these is the Nariva reserve. Here forest, marsh and mangrove merge. Several of Trinidad’s larger mammals can be found in Nariva. The monkeys are the noisiest and most visible, especially the red howlers. They have a pronounced social hierarchy. The dominant male asserts his superiority with loud guttural calls. They feed on a variety of fruit and leaves and will sometimes peer down from the canopy to view the casual visitor. In the heat of the day activity slows down and the troop will select an appropriate tree to pass the time resting.
Their smaller cousins, the white-fronted capuchins, are not quite so noisy but very lively and highly sociable. A favourite food is the fruit of the cocorite palm but they feed also on shoots and leaves. As with the red howlers grooming is an important social ritual. They seem naturally playful creatures with an evident enjoyment in each other’s company. Another noisy denizen of the Nariva swamp forest is the cicada or segal. Their shrill call practically drowns out every other sound as they announce a coming rainstorm. The porcupine is normally nocturnal but it can sometimes be seen in the day making its slow way through the upper branches.
Where the forest meets the marsh is home to a wide range of plants and animals, including the endangered manatee. At night the spectacled caiman patrols the channels in search of a meal; a bird, crab, fish or another reptile will do. The caiman is not fussy. Another Nariva predator is the anaconda, the largest snake in the western hemisphere. All snakes in Trinidad are severely persecuted. A few like the corals and the fer-de-lance are indeed dangerous, but most are harmless and are an important part of the animal community. Despite the national antipathy towards snakes, the anaconda survives in Nariva Swamp where it is at home on land and in the water.
In the early mornings the red bellied macaws leave their roosts in the moriche palms and royal palms fringing the swamp to forage in the forest surrounding the Nariva wetland and the nearby Aripo Savanna. The macaws breed in the hollow stems of dead palms. Potential nesting sites are scarce properties and often fought over. At Nariva efforts are underway to reintroduce the blue and yellow macaw. This species previously inhabited the swamp but was wiped out through poaching and habitat destruction. For the first time in over forty years the blue and gold macaw has once again a home in the Nariva reserve.
Where the river eventually reaches the sea, especially along the east and west coasts of Trinidad, rich mangrove swamps develop. Sediment brought down by the rivers is deposited at the river mouth, supporting stands of mangrove and on the western coast, extensive coastal mudflats. The mud is a resource shared by many resident and migrant birds, each species exacting its share by means of differing feeding techniques. Herons patiently stalk fish or crabs they capture with a sudden lunge. This contrasts with the sandpipers as they gather food from the surface. Scarlet ibis are among the deeper feeders often plunging their beaks in so that their faces are pressed into the mud as they hunt for fiddler crabs.
The black skimmer sports one of the more remarkable bills. The lower mandible projects well beyond the upper half in a most peculiar manner, the value of which is evident when feeding. The bird flies low over the water, slicing the surface with its knife-like lower mandible. When it detects a fish or shrimp its bill snaps shut. As small fish are attracted to the disturbance the skimmer will often trace the same path again and capture the curious. This tactile feeding method is well suited to the calm murky water with poor visibility.
The Caroni swamp on the west coast supports large numbers of scarlet ibis. They have recently resumed breeding here in small numbers after a long period when they bred only on the mainland. They are one of the island’s principal tourist attractions and have been recognized as Trinidad’s national bird.
Unlike the calm waters and mud flats of Trinidad’s West coast, Tobago, on its east coast, has clear water and crashing waves. A different complement of seabirds lives here, typified by the tropicbirds of Little Tobago. Tropicbirds range throughout the world’s tropical oceans feeding on squid and fish. Tiny islands near rich feeding grounds and relatively safe from predators provide good nesting sites. Relative is the operative word. Tropicbirds nest on the ground but choose steep cliffs, difficult for terrestrial predators to access, but they can’t prevent an attack from the air. Magnificent Frigatebirds living up to their other name of man of war birds, while not predators, are pirates. After a long day of fishing tired tropicbirds return to feed their young. The man of war birds, after lazily floating on updrafts for much of the day, lie in wait. Their technique is to harry the incoming tropicbirds and force them to regurgitate their prey. The thief then picks off a free meal. It appears that not all frigate birds have this villainous habit. Some individuals depend on their own fishing ability but others appear to specialize in a piratic lifestyle targeting tropicbirds, boobys or other species.
Along sandy beaches, especially those of the north and east coasts of Trinidad, the leatherbacks, largest of all turtles, lumber their way ashore to lay their eggs. This occurs between the months of March and June, --usually at night, but at peak season turtles may be seen completing their task well past dawn. After excavating a neat hole above the high water mark and carefully depositing her 80 or so eggs, the female leatherback delicately refills the hole and packs down the sand. She then camouflages the nest with scoops of sand and with much effort hauls herself back down the beach and returns to the sea.
Nesting is a time of great danger for the turtle for while a powerful swimmer in the ocean, she is vulnerable to poaching on land. At least at the beaches of Matura and Grand Riviere she can feel a measure of security as the local communities provide protection for the turtles. Thanks to their efforts the nesting sites now rank as the second largest in the world.
The leatherback eggs hatch after about 60 days. For the baby turtles the journey from the nest to the water’s edge is a perilous one with further dangers at sea; but those who survive may one day return to the same beach at which they were born to lay their own eggs.
The leatherback turtles at Matura and Grand Riviere and the blue and yellow macaws of the Nariva reserve have a lesson to teach us. It is that while we enjoy their presence and they enrich our lives, they can do so for only as long as we look after them. We must be their custodians and the custodians as well of all the other creatures that inhabit our wild places. We in Trinidad and Tobago are a young nation. The experience of older nations is that as a country develops and the needs of society are met, the urge for natural surroundings grows stronger, but often only after much has been lost. So, with our enjoyment comes responsibility. A responsibility to ourselves and to the world to play our part in supporting the welfare of all the worlds creatures and to ensure that our golden tree frog, ocelated gecko, luminous lizzard and pawi remain a part of the world’s biodiversity and a continuing source of wonder and enjoyment for our people at home. |
