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In recent decades, the number of Marbled Murrelets, a seabird of the Pacific coast, has declined. Scientists in Canada and the US have analyzed the chemical composition of murrelet feathers - some from birds carefully preserved since 1894 by the Burke Museum in Seattle. The analysis shows that the diet of the murrelets has changed dramatically in the last 40 years, to smaller and smaller prey items, which take longer to find. This means that adult murrelets are away from their nests longer, leaving the young birds unprotected.
BirdNote®
Marbled Murrelets’ Changing Diet
Written by Todd Peterson
This is BirdNote!
[Calls of Marbled Murrelets and waves]
In recent decades, the number of Marbled Murrelets, a seabird of the Pacific coast, has declined. Why?
To shed light on this mystery, scientists in Canada and the U.S. analyzed the chemical composition of murrelet feathers – some from birds carefully preserved since 1894 by the Burke Museum in Seattle. The analysis shows that the diet of Marbled Murrelets has changed dramatically in the last 40 years. Rob Faucett, manager of the ornithology collection at the Burke, explains:
[G4T2 8:43] As you go back in time, marbled murrelets are eating bigger and bigger prey items … In order to fill their stomachs and the stomachs of their babies they only need to catch one prey item.
Before the 1970s the birds were finding and eating relatively large fish such as anchovies and sardines. In the mid ‘70s, the birds’ diet changed to smaller fish of lower nutritional value. In the early 1990s, it changed again, to krill and other tiny invertebrates.
G4T2 10:20…If you have to spend hours and hours and hours to fill up your stomach because all you can find to eat is krill then you are leaving your nest for a much greater period of time and essentially putting your offspring and yourself at greater risk.
[Calls of Marbled Murrelets from within the forest]
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Calls of the Marbled Murrelet provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by K..S. Nelson
Producer: John Kessler
Executive Producer: Chris Peterson
© 2012 Tune In to Nature.org December 2012 Narrator: Mary McCann
ID# SOTB- MAMU-DNA-01-2010-12-24
Todd Peterson
Writer
Mary McCann
NarratorSights & Sounds
