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The atoll of Tetiaro is a string of tiny islands in French Polynesia, about 60km away from Tahiti. The islands \\u2013 known as \\u2018motus\\u2019 to local Polynesians \\u2013 are unique ecosystems that are crucial nesting sites for native seabirds.\\n \\nBut invasive species threaten to disrupt these fragile environments \\u2013 a fate seen across many islands in the Pacific.\\nRats arrived with early human settlers and have driven bird species off some of the islands. Meanwhile introduced mosquitoes have thrived in the warm conditions, and now act as vectors for diseases such as the Zika virus. \\n \\nRat eradication experts have travelled to one of the uninhabited islands in the atoll, called Reiono, to attempt an experimental eradication of thousands of rats with one mammoth poison bait drop. They\\u2019re also using this as an opportunity to better understand why eradication attempts have been less effective on tropical islands.\\n \\nAt the same time, on another island in the chain called Onetahi, researchers are releasing swarms of sterilised male mosquitoes to try to rid this motu of the disease-carrying pest.\\n \\nJoin Carl Smith from ABC Australia for the third episode of The Chase: a special four-part series about science on the run.

Picture: The Pacific rat (Rattus exulans) is smaller than many other invasive rat species, but it\\u2019s still been linked to localised extinctions of island birds, Credit: Carl Smith