Monday, September 17, 2012

The Nene Goose Story

Before the first canoes arrived Hawaii was a kingdom of birds. Hawaii was a much different place prior to human contact. Birds and insects were the only land animals able to colonize this remote group of islands. There were no land mammals or reptiles. Under these conditions, flightless bird species evolved in the islands. The largest were "true geese" related to the Nene and Moa Nalo ("vanished fowl") related to babbling ducks. They lived all over the islands as recently as 1200-500 years ago. Now all are extinct.

Ancient Fowl of Hawaii Were Grounded For Life

Ancient fowl of Hawaii were territorial. They evolved greater size and weight with larger feet as they gradually lost their ability to fly.

Flight was not needed in prehuman Hawaii because there were no ground-living predators and migration to other regions was unnecessary. Flightlessness has evolved on many isolated Oceanic Islands. Flightless birds were the first to go extinct when humans settled on the islands. They were defenseless against the territorial predators that people introduced.

The Nene Recovery Story

Nene was once abundant in a variety of habitats throughout the island until humans arrived.

Polynesians introduced mammals, modified lowland areas for agricultural crops, and exploited Nene for food.

Westerns almost hunted the species to extinction until hunting was banned in 1907. Recovery of wild Nene populations began on opposite ends of the globe in 1949. Two Nene pairs from a captive flock on Herbert Shipman's Big Island Ranch began the captive breeding program at the Wildfowl Trust in Slimbridge, England and Pohakuloa, Hawaii.

Beginning in 1960, year-old captive reared Nene were released on Maui and the Big Island to boost the numbers of Nene living in the wild. They were released in the high mountains because, at the time, it was thought this was their preferred habitat.

Controlling Predators is Necessary for Nene Recovery

There were no native land mammals or reptiles in the ancient Hawaiian environment. Humans introduced mongoose rats, cats, dogs, and pigs that feed on Nene eggs, goslings and/or adults.

Defenses of ground-dwelling Nene continue to be relatively ineffective against these predators. Goslings and molting adults are especially vulnerable because they cannot fly.

It is very difficult to remove all predators from Nene habitat. Feral dogs and pigs must be hunted from large tracts of land or fenced out.

Feral cats must be caught in traps. Poison bait stations and traps are used to control mongoose and rats in the vicinity of nesting and brood rearing Nene.

Vehicle traffic is a new kind of danger. Adult Nene is often killed by cars in places were people feed them along the roadside.

People Saved Nene From Extinction

In 1950 there were only 30 Nene left in the wild, from an estimated 25,000 in 1800. Captive breeding saved the Nene but has not restored them to their former numbers.

Since 1960 more than 2,300 Nene have been raised in captivity and released on four islands. Many of these have not survived and there are still only about 1,300 Nene living in the wild.

Loss of breeding habitat and introduced predators, such as mongoose, rats, cats, and dogs, challenge the ability of wildlife managers to restore the Nene to its former range. Only the population of Kauai is growing. This is due in large part to the fact that the on goose has never been introduced to this island.

Nene Hawaii Goose

Hawaii's state bird, Nene is found naturally nowhere else in the world. Unlike other geese, Nene is non-migratory and have adapted to terrestrial life. Their feet are padded with reduced webbing, creating longer toes for climbing on the rocky lava flows. Nene has a variety of calls, including the usual "honk" of similar geese. It is also reported that they make sounds while feeding which is described as a low "any-nay." Vocalizations often accompany many postures.

Monogamous, the Nene breeding season corresponds with the wet wirer season in Hawaii, when most plant growth occurs. They have the smallest range of any species of goose and have endured a long struggle against extinction.

A family begins when a young Nene, about two-years old, chooses its partner. A pair usually stays together for life, which may be up to 28-years in the wild. They return to the same area each year to hatch a new brood of 1-4 goslings.

The family stays together as a unit for about nine years as the parents teach the youngsters where to find food and how to behave around other Nene. In the summer, the family may also join with other Nene to form a small flock.

In September the parents return to their nesting brood of goslings. At this point, the offspring from the previous year are able to fend for themselves. Nene males and females have identical plumage. The male is typically slightly larger and more aggressive.

At the Wildwood Wildlife Zoo, males have a numbered band on the right leg and females have the band on their left leg.

Protecting their goslings is a tough job. In December or January, a female Nene constructs a rough nest on the ground, concealed under low shrubs. She digs out a shallow bowl and then lines it with leaves and feathers to help keep the eggs warm.

As she inoculates them for 30 days, her mate vigilantly stands guard nearby, often on an elevated area. The male Nene threatens and tries to chase away anything that comes near the nest, including other Nene, predators, and humans.

After the 1-4 goslings hatch they sometimes nestle next to the mother who covers them with her wings to keep them warm. Goslings must feed on nutritious, protein-rich plants to survive. Within two days of hatching, parents and goslings trek per rough ground to an area where food is plentiful. One parent walks on each side of the goslings at all times, always vigilant of predators.

In the wild, many goslings die from predators. As a result, the Nene population in the wild has not been able to increase on its own.

Wildwood Wildlife Park has the privilege to have two pairs of Nene geese donated to our zoo by Ali and Mike Lubbock from Sylvan Heights Bird Park, Scotland Neck, North Carolina. Wildwood Wildlife Park's mission is to educate people about the importance of conservation and research, focusing on waterfowl and wetland habitats. Wildwood Wildlife Park will also place special emphasis on the captive propagation of rare and endangered waterfowl. Check out this world-renowned facility Sylvan Heights Waterfowl Center, now the largest and most biologically significant waterfowl collection in the world.