Human Impacts
Colonization by the Polynesians
The Polynesians colonized the South Pacific in 1100 B.C. and reached Hawaii between 300 and 500 A.D., introducing feral ungulates such as pigs, goats, and other livestock to Oahu. Until colonization by the Polynesians, there were no land mammals in Hawaii. The Polynesians also brought the kalo, coconut, kukui, noni, and dog. Some of these introduced, non-native species became invasive because the native species had evolved without predators.
European Arrival
On January 18, 1778, British Captain Cook discovered the Hawaiian islands while exploring the Northwest Passage. The British brought gifts and animals to trade with Hawaiians, introducing even more non-native species including pigs, sheep, horses, cattle, cats, dogs and rodents, and seeds for melons, pumpkins, and onions. The British also brought disease that killed many native Hawaiians.
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Consequences for Birds
Feather OverexploitationThe Polynesians killed native birds and plucked their feathers off as decorations for capes, cloaks, helmets, god images and leis for Polynesian kings. Feathers were also used as a form of ancient Hawaiian currency. Honeycreepers and versatile finches were most sought after for their brightly colored feathers. Hawaiians used feathers from 80,000 birds to make one of King Kamehameha I's cloaks. Fossil proof shows that over half of the endemic Hawaiian birds were killed during this period.
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Habitat DestructionHabitat destruction is caused by agriculture, logging, constant expansion of living space and exhaustion of resources. Habitat destruction includes anything from deforestation to the building of new homes or roadways, which destroys the natural habitat of native birds. Another cause of deforestation is slash and burn agriculture, which is especially disruptive because fire is not a natural part of the dry forest.
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Avian MalariaMosquitoes were introduced to Hawaii in 1827 by a ship that had mosquito larvae in their water barrels. Sailors dumped the water in a bay in Maui and the mosquitoes hatched and bit chickens, some of which had immunity to avian malaria. Many endemic birds, however, including the Hawaiian Honeycreepers had never been exposed to malaria and died soon after being bitten. Birds that survived usually live at higher in the canopy because the mosquitoes like the warmer temperatures at the forest surface.
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