[MARINE_BIOLOGY_INTERNATIONAL] Seabirds work hard to ensure survival

Seabirds work hard to ensure survival

Paige Taylor
From: The Australian

A LONG-TERM study of some of the Indian Ocean's most iconic seabirds has uncovered alarming findings.

There were 10,000 breeding pairs of red-footed booby birds on the tiny Australian territory of Christmas Island in 1989, but numbers appeared to have plummeted this year. In the past month, a survey team from Hamburg University has found just 24 nests in a coastal strip of jungle where there were 212 last year.

In previous years, there have been up to 250 nests.

The scientific community has known for years about the plight of the Christmas Island frigate birds, large black pterodactyl-like pirates that harass other birds into giving up their catch. And seabird ecologists, such as Janos Hennicke, are keenly aware of the endangered status of the island's abbott's booby, the heavy, awkward hunter that risks death daily by nesting precariously above a jungle floor alive with giant, agile and carnivorous robber crabs.

But when Dr Hennicke, and his team, looked to the supposedly prolific red-foot species of booby bird on the island to try to discover some secrets of its success, he found it wasn't thriving at all. Tiny loggers wrapped in condoms and attached to the tails of the red foots showed that, in 2007, nesting birds fished for one day at a time.

This year, Dr Hennicke and his two assistants have learned that the birds' fishing expeditions in the seas off Christmas Island now last for two days each. "They are working twice as hard to catch the same amount of food for themselves and their chicks," Dr Hennicke said. Dr Hennicke began climbing the tall rainforest trees of Christmas Island in 2004 as part of the Christmas Island Seabird Project, which is ongoing.

On twice-annual trips, he has monitored nine species in the seabird community which he has discovered hunt as far away as Java in some cases.

"What we see is that the reproductive success for all the species at the moment is very low, and we are trying to find out why that is."

Heavy rain has destroyed many nests this year, he said.

But he said there were also questions about whether rising sea surface temperatures were taking a toll.

Dr Hennicke began working on the seabird project from the University of Hamburg to create a scientific foundation for the conservation of Christmas Island's seabirds.