New Year of Nene Goslings

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Nene goslings

The San Diego Zoo’s Hawaii Endangered Bird Conservation Program (HEBCP) is excited to ring in the New Year with the hatching of the first nene goslings of the season. The state bird of Hawaii is still captive bred at the HEBCP’s Maui Bird Conservation Center in the attempt to raise the wild population to a more self-sustainable number through the propagation and release of goslings.

The beginning of winter signals the start of nene breeding season. We monitor to determine when the females start sitting on a nest and when they begin laying eggs, because the period for incubation is approximately 30 days. Nene are typically the only birds that we encourage to parent-rear their young, as opposed to artificial incubation and hand-rearing by the staff. Therefore, the majority of our duty during the incubation period is observation.

Nene eggs are pulled for candling. Click on images to view in larger format.

The one exception is when the eggs are candled around day 18 of incubation to assess fertility. If an egg is fertile, it is returned to the nest of the sitting female; however, if an egg is not fertile, it is removed from the nest to prevent contamination of the remaining eggs. Although interns like myself are unable to handle the eggs, it does provide valuable opportunities to learn from the actions of the knowledgeable staff.

On day 28 of incubation, we listen for any sound of goslings that may have hatched. The nene goslings tend to roost underneath the female for approximately two to three days after hatch before their parents take them around the enclosure. There are some changes made to promote the survivability of the goslings, which include shallow water pools and adjustments in diet. Each modification is tailored to the age of the goslings, so as the goslings mature they transition to the diet and husbandry of an adult nene.

Each bird in the HEBCP flock has a unique identification band. Every week or so, the leg bands of the nene goslings are changed, because the youngsters are growing at such a great rate, and we want to avoid any injury that would be sustained if a band were to be too loose or too tight. During this procedure, the staff is able to perform physicals to monitor the goslings’ health and to keep an eye on their body weight and development.

At the Maui Bird Conservation Center, we are ecstatic to announce the successful hatching of seven nene goslings! The three new pairs of parents are taking wonderful care of them. The goslings are eating well, gaining weight, and exploring among the long grass of their enclosures.

There are currently an estimated 1,800 nene in the wild. However, with the exception of the population on the island of Kauai, nene numbers are not sustainable due to ongoing threats facing the wild birds, such as predation by introduced mammals and habitat degradation. In an attempt to keep the wild population buoyant, the HEBCP has released 429 nene since 1996. The current plan is to produce 75 goslings over the next five years, which will be released at Haleakala Ranch on Maui. This is a part of the Hawaii Division of Forestry and Wildlife’s commitment to the safe harbor agreement with these private landowners (see post Nene: Movin’ On Up). The safe harbor agreement with Haleakala Ranch will provide a well-maintained and safe habitat for the nene youngsters to be released into.

Sierra Browning is an intern at the San Diego Zoo’s Maui Bird Conservation Center.