Invasive Rat Control on Henderson Island
Visiting North Beach, Henderson Island
(Photo: Dave Williamson)

Henderson is the largest island in the Pitcairn group in the South Pacific Ocean, (latitude 24.22 S, longitude 128.19 W). It is home to breeding Henderson Petrels as well as other endemic bird species. Pacific Rats (Rattus exulans) had been killing more than 25,000 petrel chicks a year, threatening the continuing existence of this rare seabird. Fully 99 of all petrel chicks were killed within a week of hatching. The Farallon Islands Foundation was proud to contribute a gift in 2011 toward funding a remarkable, international, collaborative effort to eradicate rats on this subtropical island. This eradication effort was unique in several ways. A single motor vessel (MV Aquilea) with two helicopters conducted three separate eradication and restoration projects on a single voyage of nearly 17,000 miles.

Helicopter spreading rat bait above the plateau of
Henderson Island (Photo: Andrew MacDonald)

The three islands were:

  • Palymyra Island in the Hawaiian group (done by Island Conservation in collaboration with US Fish and Wildlife and the Nature Conservancy)
  • Phoenix Islands in Kirbati (Eco Oceania Pty Ltd), the world’s largest World Heritage site
  • Henderson Island (Royal Society of the Protection of Birds with funds from many donors in addition to this Foundation)

Henderson Island’s size of almost 11,000 acres makes it the largest subtropical island so far made rat-free (and the third-largest of all islands where rats have been eradicated, after Rat Island, Alaska and Campbell, Island, New Zealand).

The many types of species to benefit from the eradication program: in addition to the five endemic birds (the Henderson Petrel, Henderson Lorikeet, Henderson Fruit-dove, Henderson Crake and Henderson Reed-warbler), marine turtle hatchlings and seeds necessary for forest maintenance.

In other isolated island habitats, bird species have rebounded quickly from rat eradication. A trip is planned for 2015 for scientists to return to Henderson and study the impact of rat eradication on seabird and other species populations. In 2014, Farallon Islands Foundation had the pleasure of making a grant toward the planned 2015 survey.

  • 2011 grant: $7,500
  • 2014 grant: $10,000
  • Grantee: Birdlife International