While our mountain retreat offers stunning views and abundant wildlife, Costa Rica’s beauty extends far beyond the cloud forests. Today, we set our sights on the coast, where a graceful aerial acrobat awaits – the Forster’s Tern.

A Master of the Marsh

Forster’s Tern (Sterna forsteri) is a medium-sized tern, easily identified by its slender build, long, forked tail, and agile movements. These birds are at home in shallow waters, be it freshwater marshes, brackish estuaries, or saltwater coastlines. They’re not picky – as long as there’s an open area for hunting fish, they’ll be there.

Spotting a Forster’s Tern

These terns come in two distinct “looks” depending on the season. During breeding season (typically spring and summer in North America), Forster’s Terns sport a sleek black cap that extends down their neck. Their back and wings turn a pale gray, contrasting beautifully with their bright white underbelly. The bill becomes a striking black tipped with orange, and their legs turn a vibrant orange as well.

In their non-breeding plumage, the black cap disappears, replaced by a white crown. However, a distinctive black comma-shaped marking appears around the eye, making them easy to recognize. Their wings remain a pale gray, and their underparts stay white. Their bill turns black entirely, and their legs become a dull brownish red.

A Flashing Flight

Forster’s Terns are a captivating sight in flight. Their slender wings beat rapidly, propelling them through the air with impressive agility. They often hover gracefully, scanning the water below for unsuspecting fish. Once they spot prey, they dive headfirst in a spectacular plunge, often disappearing entirely beneath the surface for a moment before emerging with their catch.

Winter Visitors

Unlike many of Costa Rica’s resident birds, Forster’s Terns are seasonal visitors. They breed in North America during the summer months and migrate south for the winter. Here in Costa Rica, particularly along the Pacific Coast and the inland Southeast, Forster’s Terns become a common sight from November to April.

Finding Forster’s Terns in Costa Rica

While you won’t find these terns at our mountain retreat, there are several locations in Costa Rica where you can witness their aerial acrobatics. Here are a few suggestions:

• Carara National Park: This park on the Central Pacific Coast boasts extensive wetlands and mangroves, making it a prime location for spotting Forster’s Terns during the winter months.
• Palo Verde National Park: This dry forest park in the northwestern Guanacaste province has a network of rivers and estuaries that attract Forster’s Terns during migration.
• Maquenque National Wildlife Refuge: Located on the Caribbean coast, this refuge offers a diverse habitat, including lagoons and marshes, perfect for spotting wintering Forster’s Terns.

A Glimpse into the Elegant World of Terns

The next time you visit Costa Rica’s stunning coastline, keep an eye out for the flash of silver wings – it might just be a Forster’s Tern, gracefully hunting and showcasing the beauty of the avian world.

For more information, please view our comprehensive guide about the birds of Costa Rica

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