The Hawaiian islands are a master class in introduced animals, and on the island of Kauai, the most obvious subject is chickens. Thousands of feral chickens roam the island with no natural predators. A new study seeks to answer these questions: what are they doing there, and what can they teach us?
The Hawaiian islands, incredibly remote from any continent, were largely absent of large animals prior to Polynesian settlement in (this is disputed) somewhere between 300 and 800 AD. There were no mammals, besides some bats, and the largest animals were some mid-sized birds. Most everything in Hawaii, geologically speaking, is new, which is why imported animals can wreak so much havoc. A prime example would be the wild cattle of the Big Island, but on Kauai, a different kind of livestock has taken hold: the chicken.
Kauai is home to thousands of wild chickens, a particular variety that’s vibrant in plumage but of mixed value to the ecosystem of the island. They eat the venomous centipedes native to Kauai, a trait that people seem to like, but they have no natural predators besides pet cats and dogs, and the population is growing at an alarming rate. Some have even moved to other islands in the archipelago, like Oahu, where they’re not so welcome. But a team of researchers from Michigan State University is interested in the birds for an unexpected reason. Is it possible that the Hawaiian chicken could lead to hardier varieties of birds?
All domestic chickens are descendants of a bird called the red junglefowl, native to various parts of, mostly, Southeast Asia. Domestic chickens these days are mostly so far removed from the red junglefowl that they can hardly be compared with it, but the Hawaiian chickens are a little bit different. Polynesians brought red junglefowl with them when they settled Hawaii, and only cross-bred them with domestic chickens following Captain Cook’s landing on the archipelago in 1778. So the Hawaiian chickens are pretty recently developed from their wild form.
The study attempts to figure out the complicated history of these birds, with an eye to possibly using their hardiness to create hardier breeds of domestic chickens. It also confirmed that the Hawaiian chickens really only came into their own as the pigeon of Hawaii in the past few decades, after Hurricane Iniki destroyed chicken enclosures in 1992, releasing many of the island’s captive chickens into the jungle. You can read more from the study, published in the current issue of Molecular Biology, here.
Image via Flickr user Eli Duke