The Tongan whistler, the endemic hengahenga and other native bird species have increased in population on Mt Talau in Vava’u over the past year due to projects implemented to battle invasive species, including rats.

The Secretariat of the Pacific Regional Environment Program (SPREP) in partnership with the Tongan Government implemented numerous projects. Two projects funded by the Global Environment Fund Pacific Alliance for Sustainability joined together to help bring the positive changes in native bird population in Tonga.

SPREP stated that recent bird surveys, despite being hampered by Tropical Cyclone Winston confirmed that ongoing control of rats on Mt Talau has led to an increase in the number of Tongan whistler, Polynesian Triller and Starling. Rats heavily impact the survival and productivity of the Tongan Whistler because the birds build an open bowl nest that is easily accessed by rats.

This work also complimented other activities to protect the Mt. Talau rare endemic plant Casearia buelowii, which has been protected from pigs over the past year with the construction of a pig-proof fence.

Viliami Hakaumotu GEFPAS IAS coordinator for Tonga said it is great to utilise techniques from New Zealand successfully in Vava’u to protect our rare birds and plants, which are under threat from invasive species.

"This species of Tongan whistler is not found outside of the Vava’u Islands and the Casearia buelowii has such a beautiful flower but is only found on this one mountain," he said.

“While the first opportunities to manage invasive species are prevention through biosecurity followed by eradication, or complete removal of a species from an island, these options are not always realistic," said David Moverley, SPREP's Invasive Species Advisor.

Site or asset based invasive species management is a new concept in the Pacific but there is much to be learned from other countries such as New Zealand. 

The Global Environment Fund (GEF) funded the work to help eradicate rats on the island of Vava’u with the United Nations Environment Program as implementing agency while SPREP and the Ministry of Meteorology, Energy, Information, Disasters Management, Climate Change and Communications of the Government (MEIDECC) of Tonga as the executing agency in association with the Vava’u Environmental Protection Agency and the Mt. Talau community.