Featured Research

from universities, journals, and other organizations

Following Earth's Magnetic Field: Chemical Reaction In Birds Provides Sense Of Direction During Migratory Flights

Date:
May 14, 2004
Source:
University of California, Irvine
Summary:
Migrating birds stay on track because of chemical reactions in their bodies that are influenced by the Earth’s magnetic field, a UC Irvine-led team of researchers has found.

European robin.
Credit: Photo courtesy of University of California, Irvine

Migrating birds stay on track because of chemical reactions in their bodies that are influenced by the Earth’s magnetic field, a UC Irvine-led team of researchers has found.

The birds are sensitive even to rapidly fluctuating artificial magnetic fields. These fields had no effect on magnetic materials such as magnetite, indicating that the birds do not rely on simple chunks of magnetic material in their beaks or brains to determine direction, as experts had previously suggested.

The results are reported in the May 13 issue of Nature. The study is the first to reveal the mechanism underlying magnetoreception – the ability to detect fluctuations in magnetic fields – in migratory birds.

In the study, Thorsten Ritz, assistant professor of physics and astronomy, and colleagues exposed 12 European robins to artificial, oscillating magnetic fields and monitored the orientation chosen by these birds. The stimuli were specially designed to allow for responses that could differ depending on whether birds used small magnetic particles on their bodies or a magnetically sensitive photochemical reaction to detect the magnetic field.

“We found that the birds faced in the usual direction for their migration when the artificial field was parallel to the Earth’s natural magnetic field, but were confused when the artificial field was applied in a different direction,” said Ritz, the lead author of the paper. “Since the artificial field’s oscillations were too rapid to influence magnetic materials like magnetite, it suggests that the most likely mechanism for magnetic orientation in these birds involves tiny changes to magnetically sensitive chemical reactions, possibly occurring in the eyes of the birds – we are not sure.”

In the experiments, the robins could walk and flutter in their cages but could not fly. The birds oriented well in the Earth’s magnetic field alone, but were disoriented in the presence of a broad-band (0.1-10 megahertz) and 7 megahertz oscillating field, aligned at a 24 or 48 degree angle to the Earth’s magnetic field. When the same 7 megahertz oscillating field was aligned parallel to the Earth’s magnetic field, the robins showed normal migratory orientation again.

“Unlike our senses involving vision, hearing, smell and touch, we do not know what receptors underlie magnetoreception,” Ritz said. “Migratory birds have long been known to possess a magnetic compass that helps them find the correct direction during their migratory flights. It has remained unknown, however, how birds can detect the direction of the Earth’s magnetic field.

“Now, our study points to what we need to look for a molecular substrate for certain chemical reactions. That is, we can rule out magnetic materials in birds’ beaks and elsewhere as being possible candidates. Magnetite in the beaks, however, may play a role in detecting the strength but not the direction of the Earth’s magnetic field.”

The experiments on the birds were conducted in a six-week period in 2003 in Frankfurt, Germany, in the laboratory of Wolfgang and Roswitha Wiltschko, co-authors of the paper, who developed the behavioral experimental setup used in the study for testing magnetic orientation in birds. During migratory unrest, the birds could move in their cages. Each cage was funnel-shaped, lined with coated paper and measured approximately 1.5 feet in diameter. When the birds moved in the cages, they left scratch marks that were counted subsequently by the researchers and analyzed.

To produce artificial oscillating fields, the researchers fed high-frequency currents from a signal generator into a coil that surrounded four test cages. The coil, with a diameter of approximately two meters, could be moved to change the alignment of the oscillating field. Each bird was tested once a day during dusk for a period of approximately 75 minutes.

Besides the Wiltschkos of J. W. Goethe-Universität, Germany, Ritz was joined in the study by John B. Phillips of Virginia Tech and Peter Thalau of J. W. Goethe-Universität.

The research was funded by the Deutsche Forschungsgemeinschaft and the Fetzer Institute.

About the University of California, Irvine: The University of California, Irvine is a top-ranked public university dedicated to research, scholarship and community. Founded in 1965, UCI is among the fastest-growing University of California campuses, with approximately 24,000 undergraduate and graduate students and about 1,300 faculty members. The third-largest employer in dynamic Orange County, UCI contributes an annual economic impact of $3 billion.


Story Source:

The above story is based on materials provided by University of California, Irvine. Note: Materials may be edited for content and length.


Cite This Page:

University of California, Irvine. "Following Earth's Magnetic Field: Chemical Reaction In Birds Provides Sense Of Direction During Migratory Flights." ScienceDaily. ScienceDaily, 14 May 2004. <www.sciencedaily.com/releases/2004/05/040514030725.htm>.
University of California, Irvine. (2004, May 14). Following Earth's Magnetic Field: Chemical Reaction In Birds Provides Sense Of Direction During Migratory Flights. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/2004/05/040514030725.htm
University of California, Irvine. "Following Earth's Magnetic Field: Chemical Reaction In Birds Provides Sense Of Direction During Migratory Flights." ScienceDaily. www.sciencedaily.com/releases/2004/05/040514030725.htm (accessed August 30, 2014).

Share This




More Earth & Climate News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Volcano Erupts on Papua New Guinea

Raw: Volcano Erupts on Papua New Guinea

AP (Aug. 29, 2014) — Several communities were evacuated and some international flights were diverted on Friday after one of the most active volcanos in the region erupts. (Aug. 29) Video provided by AP
Powered by NewsLook.com
Raw: Small Volcanic Eruption in Iceland

Raw: Small Volcanic Eruption in Iceland

AP (Aug. 29, 2014) — Icelandic authorities briefly raised the aviation warning code to red on Friday during a small eruption at the Holuhraun lava field in the Bardabunga volcano system. (Aug. 29) Video provided by AP
Powered by NewsLook.com
As Drought Continues LA "water Police" Fight Waste

As Drought Continues LA "water Police" Fight Waste

AFP (Aug. 29, 2014) — In the midst of a historic drought, Los Angeles is increasing efforts to go after people who waste water. Five water conservation "cops" drive around the city every day educating homeowners about the drought. Duration: 02:17 Video provided by AFP
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) — State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins