Golden White Eye avoids the specter of an invasive snake

In the middle of the Pacific you will find buried treasures – not in the ground, but through the forests of Saipan and Aguijan in the Northern Mariana Islands. The golden white-eyed Cleptornis marchei weighs only 20 grams, but as part of the ecosystem is worth more than its gold weight. It feeds on insects, fruits, and nectar, and pollinates many of the islands' plants. It also helps another small species of bird, the Rufous Fantail Rhipidura rufifrons, find food by washing away insects as they forage. The two species can often be spotted in an unlikely procession, with the fantail following the golden white eye.

Unfortunately, this species has lived in the shadow of extinction for many years as the threat from the invasive Brown Tree Snake Boigaregularis slid ever closer to its banks. The carnivorous, nocturnal snake was accidentally brought to the island of Guam by a US military cargo ship at the end of World War II. With no natural predators, the devastation was quick. Surveys found that most bird species declined by 90% within nine years of the snake's invasion, and three bird species became completely extinct.

What is worrying is that all goods imported into the Northern Mariana Islands are shipped via Guam as both are overseas territories of the United States. When the snake settled on islands near Saipan – the largest stronghold of the Golden White Eye – conservationists feared it would become another on the long list of bird sacrifices. The sightings of the dreaded snake around Sapian's harbor seemed to confirm these fears. This looming threat led the species to be classified as critically endangered in 2004.

However, recent reports show that there have been no confirmed records of brown tree snake on Saipan for 20 years. It appears that biosecurity measures to prevent the snake from spreading are working and the predicted disaster did not occur. Coupled with the successful move of an "insurance population" from Golden White-Eyes to nearby Sarigan Island, this means that the bird's future may not be as bleak as previously thought. It's not entirely clear – it still has a very small range and habitat degradation is a growing problem. Even so, it's a beacon of hope that shows us that no extinction is a foregone conclusion.

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