Midway Atoll eradicated invasive rats after Bonin petrels had fallen to fewer than 5,000 nesting pairs

The successful removal of invasive black rats from Midway Atoll has resulted in a remarkable ecological recovery, most notably a dramatic increase in the Bonin petrel population. Once numbering fewer than 5,000 nesting pairs, the petrels have rebounded to over 135,000 breeding pairs, according to conservation research and field reports from the U.S. Fish and Wildlife Service.

Midway Atoll, a remote group of islands in the North Pacific, was once a vital breeding ground for seabirds. Before the introduction of non-native mammals, hundreds of thousands of Bonin petrels nested there annually. However, the accidental arrival of black rats from military ships during World War II drastically altered the ecosystem. The rats, finding few natural predators, spread rapidly and began preying on the ground-nesting petrels' eggs and chicks, leading to the destruction of entire breeding colonies.

By the late 1980s, the impact of the rats had reduced the Bonin petrel population to critically low levels. The invasive rodents also damaged native plant life and exacerbated soil erosion on the fragile atolls. Recognizing the severe decline, the U.S. Navy, in collaboration with the U.S. Fish and Wildlife Service and APHIS-Wildlife Services, launched a large-scale rat eradication program in 1995.

This intensive operation involved using rodenticide bait across Sand Island and Eastern Island, with meticulous planning to ensure comprehensive coverage while minimizing risks to native bird species. After extensive monitoring and verification, federal wildlife managers declared Midway Atoll free of rats, paving the way for the astonishing recovery of the Bonin petrel population and the restoration of the atoll's ecosystem.