Tiny parasitic wasp helps save one of world’s rarest birds from extinction

A tiny parasitic wasp has given a lifeline to one of the world’s rarest bird species by killing off an invasive insect that was threatening its survival.

The Wilkins’ bunting lives on Nightingale Island, part of the Tristan da Cunha group; the world’s most remote inhabited archipelago. It eats the fruit of the Phylica arborea, the island’s only native tree.

But around 2011, scientists began to notice signs of an unwelcome visitor. An invasive, sap-sucking scale insect had been, it seems, accidentally introduced on to the island by humans. These insects secrete honeydew, which encourages the growth of a sooty mould that weakens and eventually kills Phylica arborea. Their arrival threatened to destroy the forest, and the tiny bird population among with it.

This news was devastating to the scientists who study and protect the little yellow bird, as its numbers had been suffering. Huge storms in 2019 destroyed much of the forest, and surveys before the storm found there were only about 120 breeding pairs of the bird remaining.

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