Like startling flames in a sea of swamp green, we saw five Scarlet Ibises roosting far above us, in the upper branches of a dense clump of really tall mangroves. The Ibises were one of many species spotted in a recent Christmas trip to the Caroni Swamp–part of the T&T Field Naturalists' Club annual Christmas gathering held on December 7 at the Caroni Bird Sanctuary.
Sixteen field naturalists and assorted nature lovers boarded the boat captained by tour guide Shawn Madoo shortly after 3 that afternoon. We soon set off, eager to explore the swamp.
With almost 15,000 acres of biodiverse marshland, tidal lagoons, mangrove forests and intertidal mudflats, visiting the Caroni Swamp is a wonderful experience for birdwatchers, lovers of wildlife, or people who simply like the peacefulness of gliding through the wetlands.
Located on Trinidad's northwest coast, the Caroni Swamp is home to at least 20 endangered bird species, and is a wetland of global importance (it is a Ramsar site). This special place is not only a magnet for bird life–some 190 species of birds (nesting, resident and migrant) have been reported here–but it is also a valuable nursery for many freshwater and marine species of fish.
Our boat trip departed at 3.16 pm as a gawky young grey and brown Scarlet Ibis and a dapper Blue Heron (both perched on a jetty railing at the Visitor Centre) eyed the water for tasty crabs–or perhaps a frog or two. We headed west on the Number 9 Drain or Blue River.
An early sighting was a Tree Boa or Cascabel Dormillon. His five-foot-long khaki-brown body looped like a Celtic knot around an overhead branch of mangrove. He seemed very at peace with his world; his sinuous curves looped around himself as he slept in the trees. Tree Boas are mostly nocturnal, solitary, territorial animals, I discovered later. And they eat rats, birds, lizards and small birds' eggs.
Shawn was friendly, engaging, and seemed personally interested in the wildlife, telling tales of past experiences (he's been cruising the swamps for many years) and educating the newer field naturalists among us on the swamp's inhabitants.
At one point everyone on the left side of the boat had to duck as we passed beneath some low-lying mangrove branches. We paused there to observe a tiny Tree-climbing or Fiddler crab. These humble little crabs are a great example of the delicate interrelationships of life systems in the swamp: they are a major food source for many species, including the Scarlet Ibis. The crabs' tiny bodies contain the red chemical pigment B Carotene, which is what gives the Scarlet Ibis its beautiful, startling red colour.
Shawn's practiced ear recognised many bird calls, including the Yellow-breasted Flycatcher, the Northern Waterthrush, and the Straight-billed Woodcreeper.
He told us about the wealth of fish species in the swamp, including sardines, grouper, snook, herring, tilapia, and catfish, not to mention mangrove oysters, mussels, clamsand shrimp. At odd times we would hear a splash or a plunk, as fish would surface and quickly disappear.
Mangrove forests with massive arching roots surrounded either side of us as we motored slowly up the peaceful channel. We learned about the three main species of mangrove: red, black and white. The first kind we saw was the black mangrove, with strange little aerial roots growing straight up, like colonies of otherworldly fingers groping for the sky; these roots can breathe even when submerged. Later we saw red mangroves, with their complex networks of tall stilt roots that grow down into the water like giant tentacles. Red mangrove is more common further down the river, and at the seaward edge of the swamp, where saline water mixes with fresh; and these red mangrove roots are where the oysters like to live, said our guide. All three mangrove species work together to help stabilise the shoreline, trap tidal debris and provide feeding, breeding, and nursery grounds for a great variety of fish, shellfish, birds, and other wildlife.
We almost missed spotting a little four-foot black caiman, so well did his leathery ridged back blend in with the surrounding roots.
Bird sightings included a Boat-billed Heron, a Yellow-crowned Night Heron, a Tri-coloured Heron with his S-shaped neck, a Grey Heron, many Blue Herons, a Belted Kingfisher and a solid, rugged looking Common Black Hawk perched quietly on a branch. We also saw keen black and white Ospreys or Fish Hawks, which are fish-eating birds of prey. Ospreys have such good eyesight that they can see fish underwater from 100 feet in the air.
As sunlight glinted off the rippling river water, the channel widened as we approached the expansive horizon of the sea, with the sun straight in our eyes. We went out into the Gulf of Paria, with the smell of salt air and a spectacular view of Trinidad's coastline. In the distance we could see mainland mountains. Seawards, ospreys swooped.
A special surprise was the sight of a huge pelican party. Some were swimming along the bay, but they all flew up into the mangrove on our approach. Perhaps 50 or more Brown Pelicans then peered down at us from their high roosts, keeping a wary eye on us, their white heads and fantastically long bills swiveling as they tracked our location. One lone pelican remained in the water; when we approached, we realised why: it had a damaged left wing.
On our return to the swamp, we saw a Merlin (a small raptor) and a happy osprey with dinner in his beak–something with a wriggling tail.
By 5.09 pm, Shawn had parked our boat facing a large island in the middle of the swamp. Soon, three other boats joined us.
Then, from all directions in the swamp, flocks of Scarlet Ibis began arriving, intermittently at first, and then picking up the pace. Some black cormorants and tri-coloured egrets also flew in. As sunset shaded into hints of dusk, over the short time of 20 to 30 minutes, hundreds more Ibises arrived, long lines of flapping red flocks arrowing in on their favourite roosting spot on the mangrove island. It was a breathtaking display of one of nature's beautiful rituals. Each new flock haggled for its spot in the island in a cacophony of bedtime bird talk.
Shortly before dusk, suddenly there appeared long, long lines of white egrets, almost skimming the water in low-flying acts of grace, like spirits flying home. They mostly roosted below the ibises.
The green mangrove island soon looked like a beautiful Christmas forest–our own indigenous Christmas beauty: not one of vertical fir trees, but rather a sprawling, green, vibrant space, jeweled with living red and white.