Three years after field actions against the fire ants (Wasmannia auropunctata), the French Polynesia NGO Ornithological Society of Polynesia (SOP) Manu and the Matarai drone company are proud to declare ants-free the Maruapo Valley in Tahiti and the successful protection of half of the world population of a critically endangered bird (CR), the Tahiti Monarch (Pomarea nigra). The Tahiti monarch, or Tahiti flycatcher, is a rare species of bird in the monarch flycatcher family. Thanks to tireless and innovative conservation actions, the population of this endemic bird species to Tahiti in French Polynesia has now reversed declines and resulted in a population increase.

Pomarea nigra, or ‘ōmāma’o in Tahitian language, is endemic to the island of Tahiti in the Society Islands, French Polynesia. Previously common throughout the island, it became rare throughout the 20th century and was even declared as disappeared from one of the four valleys where it was observed in 1998.  In 2001, more individuals were discovered upstream in the Maruapo valley, beyond several waterfalls (Blanvillain et al. 2018).

Tahiti flycatcher  © A Petit

In 2015, a fire ant colony was discovered in contact with the monarch living at the entrance of Maruapo Valley, coming from an allotment present at the top of a 300 meters high cliff. In 2016, the five monarchs in contact with this megacolony were gone. The Tahiti flycatcher can’t survive in areas colonised by the fire ants. Between August 2017 and January 2018, 17.4 hectares of forest and steep cliffs of 300 meters high were treated to eradicate the fire ants. To implement an effective approach, the SOP Manu has innovated using drones and sole tools to be able to reach inaccessible areas.

Fire ants © C Blanvillain

No fire ant was found in March 2021 into the valley, whereas only four houses are still contaminated. Three years later, the cliff ant colony eradication is officially confirmed. This success has been enabled by a BEST project, co-funded by the country and the Punaauia district that has financially supported the SOP Manu in 2017-2018 to implement these activities. This work is pursued by additional financial support from the city of Punaauia, the Mohamed Bin Zayed Fund for Conservation, the National Geographic Society, The French government (MTE), l’Association Française des Parcs Zoologiques (AfdPZ), Victoria Zoo, and the Maru ata Union.

Mapuro Valeey, Tahiti © Matarai

The BEST project was indeed aiming at restoring the habitat of the endemic species, eradicating invasive alien species threatening the endemic bird, improving its habitat and working closely with the population who have been actively involved in the restoration of the habitats and the treatment against the invasive alien species. While only 12 individuals were observed in 1998, 103 adults, 49 pairs and 17 chicks have been observed in 2020-2021.

Like the Phoenix coming out the ashes, the Tahiti flycatcher seems to have reversed the curve with a growth rate of 1% in 1998 that jump to 17% after 2016.

Thanks to the BEST project, SOP Manu’s innovative approach has been also internationally acknowledged and is part of the PANORAMA community of solution providers as the great solution is replicable and can help other countries and islands to tackle fire ants invasion. Congratulations to the SOP Manu team and its partners!

More info of the SOP Manu, here. 

Juvenile of Pomare nigra © C Blanvillain