Biology Reference
In-Depth Information
Many birds that eat a lot of fruit have digestive tracts capable of separating out the seeds
and regurgitating them, but the Cedar Waxwing lets the seeds pass right through. Scient-
ists have used this trait to estimate how quickly waxwings can digest fruits.
TROUBLE IN PARADISE
Invasive species can pose dangers
that aren't appreciated until it's too late. For ex-
ample,theintroductionofmosquitoesontotheHawaiianIslandsposedaseriousproblem
for native humans and birds, but that problem was gravely exacerbated when nonnative
birds were introduced. These birds from other areas carried blood-borne pathogens that
they had long ago evolved immunities against. When mosquitoes bit them and then bit a
native Hawaiian human or bird, they transferred these pathogens to them.
Malaria in particular decimated both the native human and bird populations of the Is-
lands. Most native Hawaiian birds have been extirpated at the lower elevations of the
islands where mosquitoes occur. One of the concerns about climate change on Hawaii is
that warmer temperatures allow mosquitoes to spread to higher elevations, reducing the
areas where native birds can still survive.
Many of the introduced birds on the Hawaiian Islands are stunningly beautiful, but
in every case, they live in other places as well. Native Hawaiian birds, such as the Iiwi
and Apapane, are found nowhere else on the planet. Of the 71 known endemic Hawaiian
birds, 26 are extinct, and 30 of the remaining species and subspecies are listed as en-
dangered or threatened by the U.S. Fish and Wildlife Service.
Extinction Is Forever
Q I know about the Dodo and the Passenger Pigeon, but what other birds have gone
extinct in the past century?
A
The last captive Carolina Parakeet died in a zoo in 1918. Eskimo Curlews may be ex-
tinct — coordinated efforts since the mid-1980s to locate these elegant shorebirds have
failed, but isolated unconfirmed sightings even in the 2000s continue to surface so there
is hope that a few still exist.
Many researchers believed Ivory-billed Woodpeckers had become extinct until 2004,
when documented (but controversial) sightings were made of at least one male in the
Big Woods of Arkansas. Intensive efforts to locate this species in Florida, Arkansas, and
