Born out of the drift of the Atlantic plate, which formed a string of islands where it slides under the Caribbean plate, Saint Martin is located at the heart of the Caribbean Arc, or more precisely, at the North end of the Lesser Antilles archipelago.

Saint Martin is bordered on the East by the Atlantic Ocean and on the West by the Caribbean Sea.
Saint Martin has the characteristics of a dry island, with sparsely wooded hills, and a few areas with heavy vegetation. Its specificity comes from the large bands of sand shaded by sea grape and palm trees, which form the magnificent white sand beaches, which are part of the island’s idyllic decor, and from the salt ponds, the white gold of colonial times (the Arawak name for Saint Martin was Soualiga, meaning « land of salt »).

The island of St Martiin, like the rest of the Lesser Antilles, has an intertropical climate. The maximum annual temperature spread is barely more than 7ºF, and the average daytime temperature is 81ºF. In the winter, from September to March, North Atlantic depressions may reach down to our latitude, causing our temperatures to drop somewhat and a switch to northern sea swells, with light coastal floodings on the west coast. The permanent character of easterly Trade Winds sets the stage for a distinction between « windward » and « leeward » coasts, which have different micro-climates. With the moderate elevations in St Martin the « foehn effect » is negligible ; however, with a N-S orientation, the crestline is perpendicular to the Trade Winds’ direction, reinforcing the orographic rains phenomenon. These rains are abundant on the summits and particularly so on the leeward hillsides, whereas the windward side is more or less free of precipitation. This dryness of the windward coast is exacerbated by the constantly blowing winds.

In St Martin, if there is a seasonal variation in the precipitation amount, the contrast between dry and rainy seasons is much smaller than on islands further South, such as Guadeloupe and Martinique. The term rainy season is usually associated to the hurricane season, which extends from June to December. Among the most memorable hurricanes that visited St Martin are DONNA, which hit the island on Sept. 4, 1960 ; ELOISE, which barely missed us in 1975 ; DAVID, on Aug. 29, 1979, followed by FREDERIC on Sept.2, 1979 ; and HUGO, on Sept. 16, 1989.

C. HENOCQ

The different types of  shoreline and underwater systems
The island of Saint Martin offers a great variety of coastal landscapes, which represent quite distinct ecosystems. In coastal areas, from the shoreline to a sea depth of 150 ft. are found rocky and sandy shores, marshy areas and mangrove, large underwater sea-grass beds and coral reefs.

On Saint Martin’s many sandy beaches, the joint action of swells and shoreline drift makes for an unstable substrate and the permanent shifting of sand prevents any organism from taking permanent hold. The animals living in this environment burrow into the sediment. Animal life concentrates in clumps of seaweed and algae deposited by the waves on the beach. This is the domain of small crustaceans sand fleas and shore crabs.

In the rocky areas, often affected by wave erosion, broken chunks of rock provide support for many species of algae, which are fed on by grazing organisms such as sea urchins, gastropod molluscs such as periwinkles and West Indian top shells locally called « whelks » and polyplacophoran molluscs such as chitons. At high tide, other animals feed on the plankton brought in by the sea. One of these is a small crustacean that secretes a calcareous shell, the barnacle. Colonies of sea birds nest on cliffs exposed to the winds, where they rest after hours of flying at sea, seeking food. Most common are terns, seagulls, pelicans, frigates, phaetons and boobies.

The mangrove and marshy areas are mostly around Simpson Bay Lagoon and l’Etang aux Poissons, near French Quarter. The mangrove is a forest in water, in which grow very peculiar trees that have developed a set of characteristics that allow them to live in a salty and oxygen-poor soil. Red mangrove trees stand right in the water into which they extend their long aerial roots, and black mangrove trees stand in the inter-tidal zone.
These marshy areas are the link between the land and the marine environments, and they constitute the breeding grounds where most marine creatures reproduce. This is an extremely rich ecosystem which provides an abundance of food to young fish and plankton, a mix of sea urchin, crab, lobster, molluscs and sponge larvae. The labyrinth created by the aerial roots of the mangrove is a haven for small fish and young crabs, a shelter against larger predators. The disappearance of these marshy areas would be an ecological disaster that would cause the extinction of a large number of marine species.

When the sea is deep enough to prevent the swells from affecting the bottom, some flowering sea grass may settle on the sandy bottom and spread into fairly large fields.
Certain fish species live and reproduce in these oases. This is where the Antilles’ largest gastropod mollusc, the conch, can be found, along with the Spanish helmet, many kinds of starfish, sea cucumbers and bivalve molluscs, such as the clam, which burrows into the sand. Some of these sea grass beds can be found in Saint Martin in the bay of Cul-de-Sac and at Orient Bay.

Coral reefs develop in areas where a rocky seabed offers them steady support. They are made by polyp colonies which, by secreting a protective calcareous envelope, build very large underwater plateaus.

These large developments are home and shelter to an extreme variety of marine organisms and constitute the richest tropical ecosystem, comparable to the Amazonian forest. Certain species of fish have jaws adapted to grazing on coral polyps protruding from their calcareous « branches ». Among these are the multi-colored parrotfish and the triggerfish. The reef is also the domain of lobsters, spectacular fan coral and sponges. The most beautiful coral reefs in Saint Martin are found on the windward shore, outside the Baie de l’Embouchure, Orient Bay, Grandes Cayes, and around islets such as Pinel, Green Caye, Tintamarre and Fregate near Grand Case.

The Brown Booby (Sula Leucogaster) builds its nest on cliff tops near the sea. The female can be identified by its white plumage on the lower body.

The Phaeton (Phaeton aetherus) is identified by its long tail feathers and its red beak.

The Brown Pelican (Pelicanus occidentalis) is the most common and can be found on the islets, the lagoons and even in the bay of Marigot, where it fights for the fish leftovers at the market.

The Magnificent Frigate (Fregata magnificens) is a deep sea fish hunter whose wing span sometimes reaches over 7 feet. They can frequently be seen in the bay of Marigot and from any beach on Saint Martin and can be recognized by their V-shaped tail and their black plumage with a white throat. They use ascending warm currents to gain altitude and better locate their prey. In the mating season, the crimson throat of the males draws the female’s attention.
The Seagull (Larus articilla) displays a distinct grey, white and black plumage. It hunts for fish in groups, skimming the water’s surface without diving.

Terns live in colonies and nest further inland than the Brown Booby, in the brush or in prickly pear cacti. When disturbed, they utter sharp cries and dive toward the intruder’s head. There are several species of tern in Saint Martin. Among the most common are the sooty tern (Sterna fuscata) and the royal tern (Sterna maxima).

The Great Blue Heron (Ardea herodias) and the Great Egret (Casmerodius albus) are large migratory wading birds reaching up to 3 ft. that can sometimes be found at l’Etang aux Poissons in French Quarter.

The Plumed Egret (Egretta thula) is a bit smaller and very common in the Caribbean and in Saint Martin.

The Cattle Egret (Bubulcus ibis) is the most common wading bird and it can often be seen in the fields, looking for food near the cattle. At nightfall, these egrets get together to fly back to their night quarters in the mangrove of Simpson Bay or l’Etang aux Poissons. This migratory wading bird () only arrived in South and Central America a few decades ago. It is of African or S-W Asian origin.

The Green-Backed Heron (Butorides striatus) can often be found in the marshy areas of mangroves and ponds. It has a beautiful multi-colored plumage, with a silvery green back, reddish cheeks, a green crest and white chin and neck.

The Black-Bellied Plover (Pluvialis squatarola) is a migratory bird from North America that lives in flocks on the banks of marshy areas. The same is true of the piping plover (Charadrius vociferus).

The Black-Winged Stilt (Himantopus himantopus) is a small wading bird that can often be found in Saint Martin’s salty ponds such as Chevrise, Grand Case, French Quarter, Great Bay, Long Bay or Baie Rouge. Identification markers are the black and white plumage and pink or yellow legs. It lives in flocks and feeds on worms and small crustaceans. It sometimes reproduces in Saint Martin.

The White-Cheeked Pinktail (Anas bahamensis) is a small-sized duck, very common in the Caribbean, where it is sedentary. It can sometimes be found in the Lowlands salt ponds, but more often in the fresh water at the entrance of Philipsburg. It can be recognized by its white cheeks and red beak.

The Blue-Winged Teal (Anas discors) is a migratory duck from North America that can sometimes be seen in the briny ponds, mangrove and fresh water ponds.

The Osprey (Pandion haliaetus) is a large raptor that feeds exclusively on fish, whose « turf » is the vicinity of l’Etang aux Poissons in French Quarter

The American Kestrel (Falco sparverius) is the smallest Caribbean raptor (8-12 in.). It can be commonly seen in Saint Martin, in flight or perched on a tree and it can be identified by its small size, yellow belly and striped brown and black back.

The Scaly-Naped Pigeon (Columba squamosa) is a wild pigeon that lives and nests mostly in the humid middle forest, in the heights of Saint Martin. Its burgundy and blue plumage make it hard to see in the forest cover.

The Zenaida Dove (Zenaida aurita) is a dove very common in the Lowlands and on the Dutch side, where hunting is prohibited. You may occasionally see them perched on power lines or flying in pairs at nightfall. They reproduce in Saint Martin between February and November. The male and female alternate brooding.

The Common Ground-Dove (Columbina passerina) is a small brownish dove (6 in.). It is very common in the Lowlands and especially at Mullet Bay.

The Hummingbird is tiny. There are over 20 species in the Caribbean. They often sport a silvery green plumage. They feed essentially on nectar and their thin, curved bill is well adapted to their favorite flower, the Hibiscus.

The Sugarbird (Coereba Flaveola) is a small sedentary bird. It is easy to recognize, with its yellow chest, black wings and back and white stripes over the eyes. They feed on flower nectar, small insects and sweet fruit juices. They are very common on Saint Martin, and if you set a cup of sugar outside, they will gather in large numbers.

C. HENOCQ

Côté terre-ecotourisme
Côté terre-randonnées
Côté mer-le monde aquatique
http://www.reservenaturellesaintmartin.com
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In the Antilles, and specifically in Saint Martin, are found a great variety of birds, which populate every available ecosystem, from the sea and the marshes and lagoons to the dry and humid forests. Part of this avifauna is a permanent fixture on the island, while others are only making it a seasonal stopover in their migration between North and South America.

The majority of pelagic seabirds live on the heights of the rocky shores and cliffs, where they nest once or twice a year. There are still some colonies of these birds on the Eastern shore of Flat Island and on the Lowlands peninsula, at Falaise aux Oiseaux « Birds’ Cliff » in English.