Everything about Palila totally explained
The
Palila (
Loxioides bailleui) is an endangered finch-billed species of
Hawaiian honeycreeper. It has a golden-yellow head and breast, with a light belly, gray back, and greenish wings and tail. The bird is in a close
ecological relationship with the
Mamane tree. The Palila is also an
endangered species primarily due to
destruction of Mamane-
naio woodland.
Physical Description
Palilas have yellow heads and breasts, with white to light gray
plumage ventrally, medium gray plumage
dorsally, and olive-green wings and tail. The
wings and the tails are greenish. The birds also have heavy dark bills with swollen sides, a brown iris, and dark feet with yellowish soles. The Palila is one of the largest living Hawaiian Honeycreepers, measuring around 6-7½ inches (15-18 cm).
There is some
sexual dimorphism. Males tend to have brighter colors overall, as well as clear-cut black
lores. The corresponding area contrasts less with the dirty-yellow heads in the marginally smaller females.
The bird's song is inconspicuous, containing whistling, warbling and trilling notes. The call is characteristic, however, being a clear, bell-like whistle,
chee-clee-o or
te-cleet. This is loudly communicated between birds advertising food during the morning and evening, and according to native informants, it's given most frequently during the day as rain approaches (Rothschild 1900).
Systematics and nomenclature
The Hawaiian Honeycreepers (Drepanididae) are sometimes included in the true finch
family (
Fringillidae).
Oustalet scientifically described the Palila in 1877. Named
Loxioides bailleui by him, it was for some times united with several other "parrot-billed" Hawaiian honeycreeper species in
Psittirostra. Currently, the Palila has again been moved to
genus Loxioides, which was long considered
monotypic. The
native name
‘O‘u-po‘o-papale ("capped
‘o‘u") probably refers to this species too (Rothschild 1900, FWIE 1996). Despite its bill and habits being somewhat similar to the ‘O’u, its color pattern betrays a very close relationship with the genus
Telespiza.
Distribution and status
Currently, the Palila can be found only on the upper slopes of
Mauna Kea on the island of
Hawaii. Palila lives from about 6,500 ft to 9,500 ft (2000 m to 2900 m)
AMSL. The
population density of the bird increases in areas where Mamane grows more plentiful, and the birds don't appear to venture far from Mamane stands. Essentially, this means that the species is confined - and may always have been so - to the area above the
rainforest belt at around 3,000-4,500 ft (900-1400 m).
Palilas are today found in less than 10 percent of their historical range; they were found at elevations down to 4,000 ft. (1200 m) as late as the 19th century.
Loxioides bailleui was abundant throughout Hawaii until the beginning of the 20th century. It lived on the upper slopes of Mauna Kea, the northwest slopes of
Mauna Loa, and the eastern slopes of
Hualalai. Then, as early as 1944, scientists believed the bird almost extinct.
On
March 11,
1967, palilas were listed as an
endangered species under the
ESA. In 1975, it was estimated that only 1,614 palilas existed. In 1978, federal
courts ruled to remove
feral sheep and
goats from critical
habitats of the bird. From annual counts between 1980 and 1996, variable estimates of population ranged from 1,584 to 5,685 mature birds, though there are no consistent trends. In 1997, the west slope of Mauna Kea contained 72% of the population. The entire population, an estimated 4,396 birds, occupied an estimated 78 km² (BLI 2004).
Ecology and behavior
The palila favors dry Mamane and Mamane-naio
forests. A
habitat mix containing, apart from said forest, patches of
grasslands,
pukiawe shrubland on
lava fields, and other types of native
understory vegetation is optimal for their survival.
The diet of the palila is almost exclusively the immature seeds of
mamane when these are available. These contain much vile-tasting
phenolic compounds in the
seed coat and a lethal amount of
quinolizidine alkaloids in the
embryos themselves. By some as of yet undetermined means, adult palila are able to cope with a dose of these
toxins that would kill other small animals in mere minutes. The amount of toxins in mamane varies, and the palila can be seen to avoid certain trees. It is possible that these contain the highest amounts of poison, but how the birds would be able to recognize this isn't known (Banko
et al. 2002).
The bitter taste of the seed coats probably doesn't affect the birds (see below). Nonetheless, the seed coats are not very nutritious, and are thus discarded. Palila bills are adapted to open
Fabales pods. The birds hold the pod with one foot and pry it open with the bill to expose the seeds. They then tear away the visible portion of the seed coat and extract the embryo, leaving the remaining coat in the pod. Seeds that drop out of the pod intact during opening are picked up and positioned
longitudinally in the bill. The seed coat is then neatly cut open by the bill's edge and the embryo nudged out with the bird's tongue. The seed coat, still remaining in one piece, is then dropped.(Banko
et al. 2002)
Palilas also eat
naio berries and other fruit (such as the introduced
Cape gooseberry: Rothschild 1900), and mamane
flowers, buds, and young leaves. Additionally, they feed on
caterpillars, particularly those of
Cydia species (Mamane coddling moths) and more rarely on those of
Uresiphita polygonalis virescens (Mamane snout moth). These caterpillars as well as other
insects, along with the very nutritious mamane seeds, provide the Palila's main source of
protein. Nestlings, apparently not yet able to cope with the amount of poison contained in the seeds, are fed to a large extent on
Cydia caterpillars. These destroy or discard the Mamane's toxins they take up with their food, so that the caterpillars themselves are non-toxic. They do contained high amounts of phenolic compounds they probably
sequester from their food and quite likely taste as bad. The palilas don't seem to mind the adverse taste or are physically unable to perceive it, given that they go at great lengths to obtain this food during breeding season. (Banko
et al. 2002)
The abundance of mamane seeds affects
reproduction rates and adult survival. Palilas start to eat the seeds at higher elevations and then gradually move downslope. During
droughts, when mamane seeds are scarce, most birds don't even attempt to
breed.
The birds breed from February up to September. The female constructs a loose, cup-shaped
nest of some 4 in (10 cm) diameter high up in a mamane or naio tree. For this it uses
grasses,
stems,
roots,
lichen, and branch
bark from the mamane trees provide the building material. Lichen and small
leaves layer the inside of the nest. Usually the palila clutch size is two
eggs. Both parents
regurgitate food to feed their young. The
juveniles remain in the nest for up to 31 days before
fledging.
Legal Background
The Palila (Loxioides bailleui) was the first animal to have a 9th district federal case cited in its own name. Prior to Palila v. Hawaii Dep't of Land & Natural Resources 852 F.2d 1106 (U.S. 1998), cases were cited under the represented party for example Lujan v. The defenders of Wildlife 504 U.S. 555 (U.S. 1992), this citing error opened a door for environmental protection agencies who in prior years had lost on issue of standing, for example Lujan. As the Circuit Court Justices so aptly realized the fact that this bird had “winged itself into court” represented a major stepping stone for animal rights activist.
Counsel: For PALILA, Plaintiff - Appellee: Michael R. Sherwood, Esq., Earthjustice Legal Defense Fund, San Francisco, CA.
Judges: Before: HUG, TROTT, and WARDLAW, Circuit Judges.
Further Information
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