Talk about a working mother.
A Christmas Island frigate bird named Lydia recently completed a 26-day journey over 4 000km — across Indonesian volcanoes and some of the busiest shipping lanes in Asia — in search of food for her baby chick.
The trip, tracked with a global positioning device by officials at Christmas Island National Park, is by far the longest known non-stop journey by this critically endangered sea bird.
Previously, the black-and-white scavengers with the distinctive pink beak were only known to fly distances of a few hundred kilometres from their nesting sites and would be away for only 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, which is the only breeding site for the birds.
”The thing that really surprised me is that it was a long non-stop journey and that she crossed overland over volcanoes,” he said. ”Normally, you would expect the sea birds to fly over the sea.”
The trip for Lydia started on October 18 from Christmas Island, located in the Indian Ocean about 500km south of the Indonesian capital of Jakarta and 2 600km north-west of the Australian city of Perth.
Leaving a baby chick in the care of her partner, Lydia then headed south into open waters to scavenge for fish stolen from other seabirds. She then circled back on October 26 and headed between Indonesia’s main island of Java and Sumatra. From there, she flew across Kalimantan island on November 9 before flying back over Java and returning to her nesting site on November 18.
Though a long journey, it still falls short of the world record, round-the-world trek of 46 days held by a grey-headed albatross, according to Birdlife International, which monitors threatened species.
Lydia is one of four Christmas Island frigate birds being fitted for the first time with the satellite tracking device. Funded by a grant from American Bird Conservancy, the devices — a small metal box with an antenna attached to the bird’s back — allow scientists to get much-needed data on the birds’ flight paths and feeding patterns.
Until now, most of the data gathered on the frigate birds came courtesy of bird watchers who documented it turning up mostly in Asia but as far away as Kenya.
Officials are hopeful the new set of data can lead to improved 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 world’s most threatened seabirds,” said Ed Parnell of the British-based Birdlife International. ”This new satellite-tracking data will add enormously to our knowledge of the species.”
James said the distance travelled by Lydia raises some serious questions in terms of efforts to stem the decline of the Christmas Island frigate bird, which has seen its numbers fall by 10% in the past 20 years.
”We’re surprised she would have spent that long away from her nest when she had a chick,” James 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 also said the path taken by the bird raises concerns, especially since it was travelling over industrial areas, mining sites and waters popular with industrial 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.” — Sapa-AP