Bird Flies 2,500 Miles for Baby’s Food
BANGKOK, Thailand — Talk about a working mother. A Christmas Island frigate bird named Lydia recently made a nonstop journey of just over 26 days and covering nearly 2,500 miles – across Indonesian volcanoes and some of Asia’s busiest shipping lanes – in search of food for her baby.
The trip, tracked with a global positioning device by scientists at Christmas Island National Park, is by far the longest known nonstop journey by one of these critically endangered seabirds.
Previously, the black-and-white scavengers with distinctive pink beaks and wingspans of up to 8 feet were known only to fly a few hundred miles from their nesting sites, staying away for just a few days at a time, officials said.
“It’s a real revelation,” said David James, coordinator of biodiversity monitoring for Christmas Island National Park, the birds’ only known breeding ground.
“The thing that really surprised me is that it was a long, nonstop journey, and that she crossed overland over volcanoes,” James said. “Normally, you would expect the seabirds to fly over the sea.”
Lydia’s trip started Oct. 18 from Christmas Island, an Australian territory in the Indian Ocean about 310 miles south of Indonesia’s capital, Jakarta, and 1,600 miles northwest of Perth, in western Australia.
Leaving a baby chick in the care of her partner, Lydia headed south over open waters – probably to steal fish from other seabirds, a common habit among frigate birds.
She then circled back on Oct. 26 and flew between Indonesia’s Java and Sumatra islands. From there, she headed across Borneo island on Nov. 9 before flying back over Java and returning on Nov. 14 to her nesting site, where she likely regurgitated a meal for her chick.
Though the journey was a record for a frigate bird, it falls short of the top trip among birds monitored by scientists – a 46-day round-the-world trek by a gray-headed albatross, according to Birdlife International, a Britain-based conservation group that keeps track of threatened species.
Lydia is one of the first four Christmas Island frigate birds to be fitted with a satellite tracking device. Funded by a grant from the American Bird Conservancy, the devices – metal boxes about 2.5 inches long and 1 inch wide, with an eight-inch antenna – are attached by harnesses.
They give scientists much needed data on the flight paths and feeding patterns of frigate birds. Previously, most such data came courtesy of bird watchers, who have reported frigate birds turning up mostly in Asia, but as far away as Kenya in east Africa.
Officials hope the new satellite data will help improve conservation efforts.
“With only around 1,200 pairs confined to this small island in the Indian Ocean, the Christmas Island frigate bird is one of the worlds most threatened seabirds,” said Ed Parnell, spokesman for Birdlife International. “This new satellite tracking data will add enormously to our knowledge of the species.”
James said the distance Lydia traveled raises some serious questions about efforts to stem the decline of the birds, whose numbers have fallen by 10 percent over the past 20 years.
“We’re surprised she would have spent that long away from her nest when she had a chick,” he said. “That begs the question: Why does she need to go that far? It raises the suspicion that fish resources around Christmas Island are not currently adequate. That might explain the slow and gradual decline of the bird.”
James and Birdlife officials said Lydia’s route also raised concerns, since it covered industrial areas, mining sites and waters popular with commercial fishing fleets.
“It is tragically ironic that while Lydia nests on one the world’s most remote and pristine islands, she makes her living in some of the most degraded seas on the planet,” James said. “Fishing pressure is huge and marine pollution is severe.”