Warning: Breeding season for coastal and seabirds is upon us again

American oystercatchers also breed on the island during the breeding season of mid-March to the end of June.

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Most bird species on Curaçao are very pragmatic with regard to their breeding period. If it rains and there is enough food, birds will breed. Or in some cases such as the Crested Caracara, when it gets drier and there is more bait and carrion they will breed. However, coastal and seabird species do have a definite real breeding period on the island, with various species especially coming to our island to breed. And that period is now, at the end of March! This article also serves as a warning to anyone using the breeding grounds for recreation. You too can contribute to a successful breeding season. How? Read more!

Laughing gulls dancing ritual.

Coastal and sea birds that breed on Curacao

There are several water- and shore bird species on our island that can be found all year round and also breed on our island. Think of ducks such as the White-cheeked pintails and Black-bellied Whistling ducks, Caribbean (American) coots, and American gallinules, which can breed all year round if there is enough food available. Wading birds such as the Makamba or Black-winged stilt also breed on the island and can do so all year round, although the majority of breeding behavior falls in a fixed period, a period that coincides with the breeding period of several other coastal and seabirds. The same applies to plovers such as the Wilson’s Plover and the Killdeer.

As the breeding season approaches, more and more tern species gather on the island, often in mixed groups, such as these Sandwich Terns (with yellow/black beaks) and the Royal Terns (with orange beaks).

In addition, there are birds that come to the island especially (also to Bonaire and Aruba, by the way) to breed and can only be seen during this breeding season. Outside of that, they are a very rare sighting. Think of tern species such as the Least tern, the Sandwich tern, the Common Tern, the Sooty Tern, and the Bridled Tern. Species all called ‘meuchi’ in Papiamento. The Royal Tern and the Laughing Gull also breed in the same fixed breeding period on the island, but can also be observed on the island throughout the year.

Wilson’s plover adult and chick in the saltpans of Jan Thiel.

Breeding time and mating behavior

In which time frame does this breeding period for terns and laughing gulls, Black-necked stilts, Killdeer, and Wilson’s Plovers fall exactly? Their breeding season roughly lasts from mid-March to mid-August (it varies a little each year). Laughing gulls and Royal Terns can be found on the island all year round, but about mid-February changes start to appear in the appearance of the birds. Laughing gulls that are white-gray in color outside the breeding season suddenly develop a dark brown head and wingtips and the bill and legs turn red. Royal terns get a deep black cap on the head, and the bill changes from normal orange to bright orange-red. These are all signs that the breeding season is approaching, the birds are changing into their breeding plumage to have a greater chance of successfully finding a mate. From the end of February to the beginning of March, more and more Royal Terns, and Laughing Gulls come to the island and other tern species also start to assemble along the coast. Species that you hardly see outside the breeding period, such as the Least tern and the Sandwich tern. When they arrive they are often in a transitional phase in terms of breeding plumage, and the different species often mix in large groups along the coast of the island and on Klein Curaçao. The groups make an enormous amount of noise and there seems to be hardly any order and regularity, all the more because there are different species mixed together. But if you observe carefully and also take the time to look at the dynamics in the group, you will soon see that the large group consists of subgroups of the same species together with careful attempts to start partner relationships.

The chick of a Wilson’s Plover almost completely coincides in color with the substrate. Pieces of fishing line can be fatal to these little ones. Because the plastic wraps around the legs of the animals, they become entangled and die.

The final choice of a partner is the result of a ritual that differs per species. However, most species have a phase where a present in the form of a fish is presented to the female by the male. This is followed by the acceptance or decline of the present by the female. If the present is accepted a ritual in which the mates perform an extensive dance together follows, both to confirm and reinforce the choice of the mate. Later, during the incubation of the eggs, this ritual of giving presents and strengthening the partner bond will be essential for successfully rearing the offspring. Only when the partner bond is really well developed, does a mating take place, in which the male maneuvers himself on top of the female to rub the cloaca’s against each other, something that often takes no longer than a second or 2. The ease and success with which the male handles himself on top are illustrative of his experience in the matter and if you are watching a young inexperienced male or one who has done it before. As soon as fertilization has taken place, the ‘building’ of the nest follows.

Eggs of the Black-necked stilt look like tiny limestone rocks.

Building the nest – locations

Coastal and seabirds generally breed on the ground. This means that they build a nest that lies on the ground, preferably on and between coral stones. Usually, this nest is nothing more than a hollow between the stones, with in certain cases some algae or sea-purslane plants that serve as a softer cover for the egg(s). The terns usually breed together in large groups (breeding colonies). The group breeding not only provides protection, as more eyes see danger faster but also reduces the chance that an egg or young is stolen, for example by a hungry Frigatebird or Caracara.

Adult Black-necked stilt with chicks.

Terns like the nest to be right next to a large rock, which can then serve as a benchmark for the location of the nest and also as a shadow provider at certain times of the day. The egg is placed on the ‘bare’ surface and also has the color of the surface; limestone. The egg completely ‘disappears’ into the limestone underground and is perfectly camouflaged, making it harder for predators to find. Both parents will come regularly to oversee the egg or eggs and will occasionally sit on them. Not so much to incubate the egg, but to protect it from the fierce heat of the midday sun so that the egg does not literally boil. They will fiercely defend the nest against intruders. The parents fly up and yell loudly at an intruder, will regularly launch feces at intruders, and may even inflict injuries by pecking with their sharp beaks.

The chicks that have finally hatched also have the color of the background, again so as not to stand out.

All the coastal and seabird species, listed earlier in this article, breed in locations with limestone subsoil not too far from the sea. Areas such as the rugged coastline on the north coast (Playa Kanoa, Koraal Tabak, Hato plains, Boka Patrick, Ascencion. Shete Boka), the coastline around inner bays such as Santa Martha, Schottegat, and Piscadera Bay, the islands that lie in the middle of the salt pans of Jan Thiel and the salt pans of Boka Samí, and on the walls of these salt pans. Klein Curaçao is also a popular place for these birds to breed. However, all the mentioned locations are precisely the places that are increasingly used for recreation by humans.

Least tern with a juvenile at Playa Kanoa.

Threats to successful broods

If the tern species and other nesting coastal and seabirds are looking for an ideal nesting place to lay their eggs and raise their young, they are already very sensitive to disturbance. This is because the breeding site must meet high standards in the sense of tranquility. A little disturbance is therefore enough to make the animals decide to leave. During the breeding and rearing of the young, the breeding colonies and the individual solitary breeders (such as the Black-necked Stilt) are extremely sensitive to disturbance and the slightest disturbance in the form of (stray or unleashed) dogs, mountain bikers, hikers, or quad bikers will make them leave their eggs or chicks without coming back. With a lost generation as a result. Other destructive elements are the presence of feral cats and rats, which in many cases can wipe out entire budding colonies.

It is therefore of great importance to diminish disturbing elements at potential breeding locations during the scouting and breeding period. And that’s where the users of nature areas come in to lend a helping hand.

What can you do to help!

Behave responsibly
It is of great importance that users of natural areas that are located along the coast behave responsibly and especially observe carefully whether there is courting behavior of terns, whether aggressive behavior can be observed (in the form of the birds coming in close with a lot of noise) or coming directly at you and deviating at the last minute), and whether there are certain large groups of seabirds together. If you see this behavior, it’s important to get out of the area immediately!

Keep dogs on a leash and avoid areas with breeding activity
In addition, we ask everyone who walks dogs in coastal areas to keep all dogs on a leash until at least the end of June, and if the breeding activity is detected somewhere, at least not to walk there until the end of June. It is very important that quad riders do not drive through the areas mentioned. We also ask mountain bikers and hikers to be attentive and to avoid areas where breeding activity can be observed.

Areas where you have to be careful!
The areas where great care is especially necessary are: the Hato plains (along the coast), along the north coast from Ascencion to Westpunt, the salt pans of Jan Thiel (including the islets), the salt pans of Boka Samí, the salt pans of Jan Kok, the coastline along inland waterways such as Sint Jorisbaai, Fuik, and Groot Santa Martha and the coastline of Klein Curacao.

If you observe breeding behavior as described earlier in this article, please report this together with the location where the behavior was observed via info@curassavica.com or via the Facebook page Bird Watching Curaçao in a private message. We can then issue targeted warnings for the areas that will be used as breeding sites this year.

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