What creature lives on a volcano, eats poisonous seeds, and is in danger of extinction? It’s not a dinosaur, it’s the palila!
The palila is a small bird that most people have never heard of before. But, don’t be fooled, this bird displays surprising characteristics that have baffled scientists for years. Unfortunately, palila are in danger of becoming extinct if we don’t protect the species and its habitat.
The palila is a honeycreeper found only on Hawai’i’s Big Island on Mauna Kea, a dormant volcano and the tallest mountain in the Hawaiian Chain. Mauna Kea is flanked by māmane-naio forests, a dry, high-elevation forest and shrubland that occur in a ring around the mountain. Two main species of trees make up the native forests in this area: the māmane and the naio.
Adult palila feed almost exclusively on māmane seed pods,
Close up of a palila sitting in a tree. Photo Credit: Paul Chang, U.S. Fish and Wildlife Service
Māmane seed pods are the main source of food for palila. Photo credit: Paul Chang, U.S. Fish and Wildlife Service
which has baffled scientists for years because the seed pods are in fact poisonous but don’t affect palila negatively. Palila also primarily nest in the māmane forests.
Unfortunately for palila, the māmane forests are favored by non-native feral sheep and goats as well. There are three types of sheep on the Big Island: the feral domestic sheep; the
European Mouflon sheep, an introduced species; and hybridized offspring of the two. The feral sheep and goats destroy the māmane trees, making it difficult for the endangered palila to nest and find food. Sheep and goats kill sprouting trees by eating new māmane shoots. Māmane takes about 20 years to reach the size needed to support palila. The sheep and goats also kill older larger trees by eating the bark off the trunks. When a tree is stripped of its bark, it cannot transport nutrients to the rest; the result is the slow but steady death of the entire tree. So, the sheep and goats are effectively killing off the māmane trees by not letting new trees grow and killing the mature trees.
Evidence of feral sheep damage to the māmane trunk that can lead to the death of the tree. Photo credit: Paul Chang, U.S. Fish and Wildlife Service
A herd of feral mouflon sheep on Mauna Kea. Photo Credit: Ben Kawakami Jr., U.S. Geological Survey
Palila have been negatively affected by the dwindling supply of māmane seeds and fewer choices for nesting. As a result, they are struggling to survive. Studies show that when māmane seedpods are scarce, palila lay fewer eggs and their overall survival rate decreases.
The palila was listed as endangered by the Endangered Species Act in 1967. Critical habitat was designated for the bird in 1977. The critical habitat roughly follows the boundaries of the Mauna Kea Forest Reserve. A 1978 Federal court ruling required that all feral sheep and goats be removed from palila critical habitat.
In the 1930’s, the State of Hawai’i built a 55-mile fence around the Mauna Kea forest to prevent any loss by browsing pressure from feral sheep; however, the fence has fallen into disrepair over the past 70 years and does not keep feral sheep from accessing the remaining māmane forest. Plans for a new fence have been made, but the project has not been completed yet. The palila population has been steadily declining as the feral sheep population increases.
Other factors affecting palila’s survival are: poor management of game populations, drought, feral cats, and use of high-impact recreational vehicles such as ATVs in palila habitat. Vehicle use also increases fire risk in some areas.
The palila is a rare and unique species that we need to protect for future generations.
To contact the U.S. Fish and Wildlife Service about this piece or to report a violation you have witnessed, please go to www.fws.gov/pacific/lawenforcement/ and click on the “contact us” link at the top of the page.
A four-wheel ATV rider in a race around Mauna Kea. Photo Credit: Paul Chang, U.S. Fish and Wildlife Service
Video of bark stripping damage on native trees (Naio) and browse pressure on Mamane trees. Unmanaged ungulates directly threaten the Palila with extinction.
Video of feral sheep on Hawai`i island. Poorly managed ungulates do great damage to native ecosystems and threaten the survival of rare species.