New Zealand island now rat free

This video from California in the USA says about itself:

Achieving Balance: Anacapa Island Ten Years After the Removal of the Black Rat

6 March 2013

Ten years after removing nonnative rats the ecosystem on Anacapa Island, including rare seabirds, is showing profound results of recovery.

Ashy storm-petrels are nesting on the island for the first time ever recorded and Cassin’s auklets have expanded their territories in the absence of rats as predators. Significantly, the number of Scripps’s murrelets nests has quadrupled with a 50 percent increase of eggs hatched.

Rats are known to have negative impacts to island ecosystems. Rats are the most significant cause of bird extinctions on islands and are estimated to be responsible for half of bird and reptile extinctions worldwide.

Nonnative black rats, which were first reported on Anacapa Island in the early 1900s, threatened critical breeding habitat for these rare seabirds. They were eating approximately 70 percent of the eggs of the once common Scripps’s murrelet, a state-listed threatened species. They also preyed upon native deer mice, reptiles, insects, intertidal invertebrates, and plants.

To restore balance to the island ecosystem, black rats were removed in 2001 and 2002 using an aerial application of rodenticide bait. Some of the world’s leading island experts and scientists from the United States, Canada, and New Zealand assisted project partners from Channel Islands National Park, Island Conservation, and the American Trader Trustee Council (comprised of the California Department of Fish and Wildlife, U.S. Fish and Wildlife Service, and NOAA) in the rigorous planning process for this project.

From Wildlife Extra:

Another New Zealand island declared rat free

Rodent eradication successful on Taranga Island

July 2013. There has been no sign of rodents on Taranga Island, off the Whangarei coastline north of Auckland, since a large-scale eradication took place there in May 2011. Monitoring has just been completed now that two years have passed since the aerial application of bait. No rodent sign was recorded, which confirms they have been eradicated.

The NZ Department of Conservation (DOC) and Ngatiwai Trust Board worked together on “Project Restore” with the objective of removing the rodent threat to the continued existence and recovery of the many threatened species that live on the island.

Monitoring was carried out in June 2012 and then again in May 2013 using rodent detection methods that consisted of tracking tunnels, rat traps, observations from people working on the island and rodent detecting dogs scouting the island. DOC Programme Manager Keith Hawkins says “After two years of no kiore (Pacific rats) being found we are confident that the eradication was successful. Two years allows for any kiore that may have survived the bait drop to have bred to detectable levels and be picked up by monitoring”.

Tuatara & lizards

Evidence has shown that following kiore eradications from islands the number of tuatara and lizards recover quickly. DOC expects this will happen on Taranga Island, along with huge benefits to ecosystem regeneration.

Saddleback, little spotted kiwi, red crowned parakeet, kaka, and Pycroft’s petrel

Coastal broadleaf forest covers the island that is home to saddleback, little spotted kiwi, red crowned parakeet, kaka, and Pycroft’s petrel. Tuatara, at least six species of lizard and an endemic land snail also inhabit the island.

Taranga has extensive historical features and holds spiritual significance. Taranga Island is part of the Hen and Chicken Islands group and is ranked as internationally important. As a nature reserve, Taranga is strictly a ‘no landing zone’ to protect the rare and endangered flora, fauna and local endemics that are present on the island.

Now the island is kiore free, DOC urges boaters to be extra vigilant, ensuring they are not taking unwelcome guests out with them as that is the only way they can get there. Not storing food on your boat and having traps set on board are easy measures that can be taken.

A tropical rodent eradication review has been launched to develop recommendations for improving the success rates of eradications. More than 30 experts in island rodent eradications, island ecology, rodent ecology, and toxicology came together at a meeting at the University of Auckland, New Zealand, to review historical data, analyze successful and unsuccessful projects, and discuss new ideas and approaches to increase the success rates of rodent eradications on tropical islands: here.

Related articles

• California’s Best View is From Anacapa Island, Says Magazine (kcet.org)
• Rat Invaders: Islands Fighting Back Against Killer Rodents (news.nationalgeographic.com)
• Anacapa Island (maryangeliniphotography.wordpress.com)
• With nature restored, Channel Islands dazzle (myrtlebeachonline.com)
• Once Extinct in the Wild, Galapagos Giant Tortoises Return to Pinzon Island (blogs.scientificamerican.com)
• Kill a rat, save an ecosystem (theecologist.org)
• World’s largest rat extermination rids South Georgia of rodents (guardian.co.uk)