Where When How — N/D 2017 - J/F 2018
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Our Feathered Friends A Bill Full Of Water
Kim Mortimer

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, drinking 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 mangroves, mudflats, inlets, lakes and ponds that are salt water-based or largely brackish, 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 freshwater 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 poisonous 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 primitive, 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 depressions inside their bodies. Although the gland is present in all birds, it’s only functional in species regularly exposed to salt water in their diet.

With bird anatomy being quite different 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.
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