High in the mountains of our Costa Rican retreat, the symphony of birdsong is a constant companion. But here, amongst the vibrant toucans and melodic wrens, you won’t find the sooty tern. This sleek, ocean-loving bird graces a different Costa Rican landscape – the vast expanse of the Pacific Ocean.
While not a permanent resident, the sooty tern is a fascinating visitor to Costa Rica’s shores, particularly during breeding season (which can vary slightly depending on location). So, if you’re planning a visit to the coast and have a keen eye for avian wonders, keep an eye out for this charismatic seafarer.
A Master of the Open Ocean
The sooty tern is a medium-sized seabird, instantly recognizable by its striking black and white plumage. Adults sport a jet-black back and cap, contrasting beautifully with their snowy white underparts and forehead. Immature birds take a few years to acquire their adult finery, initially appearing a dark sooty brown with white speckles.
Built for life on the open seas, the sooty tern boasts a streamlined body, long pointed wings, and a deeply forked tail – perfect for agile maneuvering and effortless gliding. With a wingspan of up to 47 cm, these birds are masters of aerial acrobatics, dipping and diving as they hunt for prey.
Speaking of prey, the sooty tern is a skilled piscivore, its diet consisting primarily of small fish and squid plucked from the ocean’s surface. But these birds aren’t solitary hunters. They often work in collaboration with other terns or even marine predators like dolphins and tuna, who drive fish schools closer to the surface, making for an easier catch.
A Noisy Neighbor (But Only for a While)
Sooty terns are highly social birds, forming massive breeding colonies on remote islands throughout the tropics. These colonies can be incredibly dense and noisy, with the constant chatter and squawking earning them the nickname “wideawake terns.” Here in Costa Rica, some potential nesting sites include Cocos Island National Park and Isla del Caño Wildlife Refuge.
The courtship rituals of sooty terns are a sight to behold. Males present potential mates with small fish offerings, accompanied by elaborate aerial displays. Once paired, they collaborate on building a simple scrape in the sand, where they lay a single egg. Both parents take turns incubating the egg and feeding the chick after it hatches.
However, once the chick fledges, it embarks on a life at sea, potentially not returning to land for several years. This makes sightings of sooty terns from the mainland Costa Rica a bit of a lucky draw. But if you find yourself on a coastal excursion during breeding season, keep your eyes peeled for these remarkable birds – a fleeting glimpse of their black and white forms against the endless blue is a memory you won’t soon forget.
While you may not find sooty terns gracing the skies above our mountain retreat, Costa Rica boasts a wealth of incredible birdlife waiting to be discovered. Stay tuned for our next blog post as we delve into the fascinating world of another feathered Costa Rican resident!
For more information, please view our comprehensive guide about the birds of Costa Rica
