Travel Reference
In-Depth Information
HAWAII'S ANGRY BIRDS VS FERAL PIGS
How delicately interdependent are Hawaiian ecosystems? Consider how pigs are
driving Hawaiian birds to extinction. Not directly, of course, but the chain of cause
and effect is undeniable.
Feral pigs, most likely the descendants of domestic pigs brought by early
Europeans, have caused widespread devastation to the islands' native wet forests.
At Hawaii's national parks, pigs are considered public enemy number-one, with
federally sponsored eradication and fencing programs. Outside of federal lands,
eradication efforts are few, and one estimate is that there may be as many as one
feral pig for every 33 state residents.
Pigs trample and kill native fauna, destroy the forest understory and spread far
and wide the seeds of invasive plants. Pigs love native tree-fern stems, knocking
them over and eating the plants' tender insides, while the bowl-like cavities left be-
hind catch rainwater and create ideal breeding pools for mosquitoes.
Common mosquitoes - presumed to have arrived in Hawaii in water casks
aboard whaling ships in 1826 - pick up avian malaria and avian pox (also intro-
duced from the European continent) and spread it to native birds, particularly hon-
eycreepers, who have lost their natural immunity to these diseases.
It's a simple equation: no feral pigs, far fewer mosquitoes, far less avian malaria
and far more honeycreepers. What's not so simple is how to make that a reality
statewide.
Feathered Friends
Many of Hawaii's birds are spectacular examples of adaptive radiation. For instance, all
56 species of endemic Hawaiian honeycreepers most likely evolved from a single finch
ancestor. Today, over half of those bright-colored honeycreepers - along with two-thirds
of all native birds - are extinct, the victims of more aggressive, non-native birds, predat-
ory feral animals (like mongooses and pigs) and infectious avian diseases against which
they have no natural immunity.
The endangered nene, Hawaii's state bird, is a long-lost cousin of the Canada goose.
Nene usually nest in sparse vegetation on rugged lava flows, to which their feet adapted
by losing most of their webbing. While eight other species of Hawaiian geese (now ex-
tinct) became flightless, nene remain strong flyers. There were once as many as 25,000
nene on all of the Hawaiian Islands, but by the 1950s there were only 30 left. Captive
breeding and release programs have raised their numbers to over 2000 on the Big Island,
Maui, Kauaʻi and Molokaʻi today.
