At the start of the program in 2019 Lord Howe Island had an estimated rodent population of 300,000 rats and mice – roughly 1,000 rodents for each of the island’s 350 residents. The animals were said to have arrived after jumping ship. Mice first appeared on the island in 1850, with rats following in 1918 after escaping from a ship that sank off the coast. They were responsible for driving several native species extinct, including five land birds, 13 invertebrates and two plant species. Next on the list was the dwindling population of the flightless Lord Howe woodhen. After concerns were raised that the birds may eat the rat poison pellets, they were moved to an isolation pen managed by Sydney’s Taronga zoo while the program took place.