Great Crested Tern

Fascinating facts about the Great Crested Tern

• A great crested tern can dive from 15 metres up and plunge into water at 60 km/h — fast enough that its eyes have evolved a special lens that reshapes mid-dive to see clearly underwater, then snaps back to focus on air when it surfaces. This optical trick happens in milliseconds and lets them spot a 10-centimetre fish from above the waves.
• These birds are nomads of the Indian Ocean and beyond: they follow monsoon winds and fish migrations across 8,000 kilometres of coastline each year, with some populations moving between Africa and Australia based entirely on where food appears. A tern tagged off Australia was recorded in Mozambique three weeks later — a journey of 5,000 km.
• The great crested tern raises its chick alone on bare rock or sand with no nest at all, and the chick's camouflaged down plumage is so effective that parents sometimes can't find their own offspring in a colony of thousands. A single missed feeding can be fatal; chicks starve in less than 48 hours without food.
• Colonial breeders nesting in groups of up to 10,000 birds, great crested terns synchronise their breeding so tightly that within a colony, 90% of eggs hatch within just seven days of each other. This timing overwhelms local predators — a predator can't eat thousands of chicks when they all fledge at once — but it means the colony must find fish for thousands of hungry mouths in the same two-week window.
• The great crested tern's pale silvery plumage acts as a heat sink: breeding adults spend up to 16 hours a day sitting on sun-baked rocks at 50°C in equatorial heat, and their light colouring reflects enough solar radiation to keep them cool enough to survive. Dark-feathered seabirds in the same habitat overheat and must abandon eggs or chicks to find shade.

At a glance

About the Great Crested Tern

As the Great Crested Tern soars effortlessly above the sun-kissed waves, its sleek, grey form glistens with a subtle sheen, like the gentle lapping of the tide itself. With a fluid motion, it tucks its wings and plunges into the depths, emerging triumphantly with a silvery fish clutched tightly in its beak, a testament to its remarkable agility and precision as a hunter. In its effortless dance between sea and sky, the Great Crested Tern embodies the very essence of the coastal realm, a true monarch of the windswept shores.

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