Emerging Science Note/It’s for the Birds
Air Date: Week of February 20, 2004
Living on Earth’s Cynthia Graber reports that some large predatory birds may start eating more small birds when fishing bycatch is reduced.
CURWOOD: Just ahead: finding the flow and the culprits that assault underground drinking water supplies. First, this Note on Emerging Science from Cynthia Graber.
[SCIENCE NOTE THEME]
GRABER: Bycatch – unwanted fish caught accidentally and thrown back in the ocean – has been reduced in recent years. That’s because the fish catch is down in general, and because new technology has helped limit bycatch. Now, scientists say that the reduction in bycatch may have an unexpected effect. Predatory seabirds may turn to eating more small birds instead of waiting for a free lunch off the back of a fishing boat.
For example, predatory birds called great skuas had been on the decline a hundred years ago. Humans shot them for food and to keep them away from small livestock. But when factory fishing boats started throwing back huge amounts of unwanted fish, the birds followed the vessels, and their numbers rapidly increased.
The great skuas’ diet usually consists of fish and smaller birds. After they eat, skuas regurgitate small pellets of the indigestible parts of their meal. For the past 30 years, scientists have been collecting these pellets and analyzing skua meals, checking for feathers, or specific types of fish bones. They’ve compared this information against official information about levels of bycatch in any particular year.
In years when bycatch has been lower, fish intake has decreased, and the eating of small bird has gone up. This change in skua diet over the long-term could decrease the numbers of small birds such as the black-legged kittiwake, a type of gull that’s already on the decline. That’s this week’s Note on Emerging Science. I’m Cynthia Graber.
ANNOUNCER: Support for NPR comes from NPR stations, and: Aveda - an Earth-conscious beauty company committed to preserving natural resources and finding more sustainable ways of doing business. Information available at Aveda.com; The Noyce Foundation, dedicated to improving math and science instruction from kindergarten through grade 12; The Annenberg Foundation; and The Kellogg Foundation, helping people help themselves by investing in individuals, their families, and their communities. On the web at wkkf.org. This is NPR, National Public Radio.
[MUSIC: The Dust Brothers “Corporate World” FIGHT CLUB SNDTRK (Restless Records - 1999)]
Living on Earth wants to hear from you!
Living on Earth
62 Calef Highway, Suite 212
Lee, NH 03861
Newsletter [Click here]
Donate to Living on Earth!
Living on Earth is an independent media program and relies entirely on contributions from listeners and institutions supporting public service. Please donate now to preserve an independent environmental voice.
Sailors For The Sea: Be the change you want to sea.
Innovating to make the world a better, more sustainable place to live. Listen to the race to 9 billion
The Grantham Foundation for the Protection of the Environment: Committed to protecting and improving the health of the global environment.
Contribute to Living on Earth and receive, as our gift to you, an archival print of one of Mark Seth Lender's extraordinary wildlife photographs. Follow the link to see Mark's current collection of photographs.
Buy a signed copy of Mark Seth Lender's book Smeagull the Seagull & support Living on Earth