Where When How N/D 2017 - J/F 2018 : Page 176
OUR FEATHERED FRIENDS A BILL FULL OF WATER MoST vISITorS CoME To ThE TurkS ANd CAICoS ISlANdS (TCI) To SEE ThE MAGICAl TurquoISE ColourS oF GrACE BAY. If you’re prepared to go oﬀ the proverbial beaten path, a visit to any of the country’s interior waterways will oﬀer a diﬀerent treat. The TCI is an archipelago almost entirely made out of limestone. The high porosity of the substrate means rivers, streams and creeks are non-existent, which leads to very little soil or nutrient runoﬀ. This, and a number of other factors, helps contribute to the striking clarity of the water found in the TCI. The majority of ponds or lakes found here are salt water or at best, brackish. Considering most birds drink some water every day, where do birds ﬁnd fresh water in the TCI? Ever-so resourceful, they scoop water up from morning dew on leaves, drink from puddles, or ﬁnd rainwater caught at the base of plants. like all mammals, birds require fresh water. But not all birds have direct access to it. In fact, some seabirds spend a great deal of their lives at sea, therefore, drink-ing salt water is the only option. The TCI boasts a large number of bird species oﬀering a diverse selection to study and understand their drinking habits. You will ﬁnd seabirds, freshwater birds and songbirds living in close proximity, but all with their own needs and practices. Being surrounded by ocean, coastal man-groves, mudﬂats, inlets, lakes and ponds that are salt water-based or largely brack-ish, it’s easy to conclude a number of birds have adapted well to the environment. A seabird, like the brown pelican, will collect rainwater in its bill when it can, but it will also drink salt water. The juvenile least grebe photographed here is a fresh-water diving bird. That being said, this photo was taken on a saltwater pond on North Caicos named Whitby Pond. The Bahama woodstar hummingbird found in the TCI does not actually drink water at all. Instead, it gets its sugar liquid from the nectar of ﬂowers. What’s more, birds diﬀer greatly in their ability to desalinate salt water. Some can drink seawater without a problem. For many others, too much salt water is poi-sonous because they cannot process a large salt intake eﬃciently. A bird’s capability to secrete salt seems to be linked to habitat, particularly its marine environment. Birds have a prim-itive, largely reptilian-type kidney that helps process salt water. The nasal gland (aka, the salt gland) acts as a desalinisation system and is located in shallow depres-sions inside their bodies. Although the gland is present in all birds, it’s only func-tional in species regularly exposed to salt water in their diet. With bird anatomy being quite diﬀer-ent from human, it’s easy to see why they don’t drink the same way. Generally, birds lack the ability to suck liquid up into their throats. Instead, most ﬁll their bills with water, then tilt their heads back using gravity to ingest it. Pigeons and doves are among the few birds who can suck water to drink while their heads are down. There are a few important freshwater ponds crucial as a main source of drinking water for many birds. Erosion of the porous limestone bedrock in TCI has led to a freshwater lens to collect beneath the surface of the islands. The lens, in turn, has spawned these freshwater ponds. Cottage Pond is a freshwater pond located on North Caicos and is a favourite spot for bird watching. You’ll see a variety of birds hunting in the water or observe seabirds (such as terns) skim a bill full of water as they swoop down for a drink. Most notably, the thick, green vegetation surrounding the pond can be the perfect escape – if you’ve had your ﬁll of turquoise. I ~ STORY AND PHOTOS BY KIM MORTIMER ~ 176 • • • • • NOV/DEC/JAN/FEB 2017/2018 “Where When How -Turks & Caicos Islands”
Our Feathered Friends A Bill Full Of Water
MOST VISITORS COME TO THE TURKS AND CAICOS ISLANDS (TCI) TO SEE THE MAGICAL TURQUOISE COLOURS OF GRACE BAY. If you’re prepared to go off the proverbial beaten path, a visit to any of the country’s interior waterways will offer a different treat.