Unusual Hawaiian Fence Serves an Important Purpose

Hawaiian FenceUnusual Hawaiian Fence Serves an Important Purpose

A fence isn’t just a fence. There are so many different variations, styles, designs, materials, and purposes that lead to unique and distinctive fences around the world. A Hawaiian fence, for example, is garnering national attention recently for its unusual purpose and placement.

The Endangered Species Problem Facing Hawaii

Hawaii is known for its idyllic vacation spots and breathtakingly beautiful scenery, but it unfortunately also has the title of the endangered species capital of the United States. The state is actually home to a third of all endangered species in America, and 78 percent of extinctions in the country have occurred in Hawaii. This is not only disheartening but also very concerning. More than half of the state’s 130 native birds are now gone, and the rest remain severely endangered.

The Invasive Species: Feral Cats

This endangered species problem is so drastic in Hawaii because, before humans arrived, bats were the only mammals that lived on the land. But now a growing human population has taken over Hawaii, along with their deer, goats, pigs, and cats. It is estimated that nearly 500,000 feral cats roam on Hawaii’s Big Island, and they are causing more than 70 percent of deaths of petrels, birds that nest deep in lava rock burrows on the slopes of the Mauna Loa volcano.

When other invasive species cause such damage to endangered species, the invasive species is usually just removed, but cat supporters strongly oppose the eradication and removal of feral cat colonies. This leaves fencing as the only solution.

A 5-Mile Long Cat-Proof Fence

In order to protect endangered native species from feral cats, Hawaii is building its fifth conservation fence to keep cats away from the birds. The fence is not only six feet high, but also is equipped with a curved, floppy top that prevents cats from climbing over it. The construction of this fence was formidable at best, as it had to be built at 8,000 to 10,000 feet on top of a volcano. Materials and workers were flown in by helicopter, commonly battling extreme heat and cold to complete construction outside of nesting seasons.


Though building of the fence was physically demanding, 600 acres of nesting habitat on Mauna Loa are now fully protected, thanks to the Hawaiian fence.