The population of nene geese at the Tracy Aviary has doubled with the hatching of four more of the rarest goose eggs on Earth.
The nene goslings made their public debut Sunday, preening, posing and pecking alongside mother goose during a photo appearance for the local press.Noting that only 1,000 of the geese exist worldwide, aviary director Mark Stackhouse said, "We're really pleased that we have four more and that they are doing so well."
The ground-nesting species once thrived on the Hawaiian Islands, where few land-based predators lived. But then the rat and the mongoose were introduced to the islands and eliminated the nene from the wilds, Stackhouse said.
"This is an example of a bird that has been saved from extinction by captive breeding. Other than a small population maintained in a tightly controlled environment on the island of Hawaii, it survives today only in captive flocks," Stackhouse said.
Tracy Aviary has two pair of nene, but only one has nested, Stackhouse said. Four eggs is the largest brood the pair has produced. Though only about a week old, the goslings are already active and voracious.
"They are gobbling up the grass more than anything we feed them. If they keep it up, we might not have to use the lawn mower in this area," he joked.
While the outlook for the nene goslings appears good, Stackhouse is worried about some of the other nesting tropical waterfowl at the aviary. Waterfowl native to the western United States don't normally breed so early in the spring, but the tropical birds at the aviary have been fooled by the premature and protracted spell of warm weather.
A number of rare birds from Australia, South America, Hawaii and other sunny climes have nested abnormally early this year, Stackhouse said. When that has happened in the past, many of the eggs have been damaged by a cold snap.
The nene were lucky that the warm weather held long enough for the eggs to hatch. "The first few days are the most precarious, but now, they're pretty much out of danger," Stackhouse said. "We're hopeful we can raise all four."
The goslings can be seen in a special enclosure on one of the grassy paddocks at the aviary. Later, they might be placed in another zoo or aviary or even returned to Hawaii, Stackhouse said. "Most likely, they will become part of another breeding program."