Earth Science News  





. For Migrating Sparrows, Kids Have A Compass, But Adults Have The Map

Two longstanding questions about migrant songbirds are how quickly they recover when thrown off course -- as they can be when they encounter powerful winds -- and just what navigational tools they use to do so. To address the two questions, the team decided to fit a group of white-crowned sparrows with tiny radio transmitters no heavier than a paper clip and track their movements from a small plane.
by Staff Writers
Princeton NJ (SPX) Nov 07, 2007
Even bird brains can get to know an entire continent -- but it takes them a year of migration to do so, suggests a Princeton research team. The scientists have shown that migrating adult sparrows can find their way to their winter nesting grounds even after being thrown off course by thousands of miles, adjusting their flight plan to compensate for the displacement.

However, similarly displaced juvenile birds, which have not yet made the complete round trip, are only able to orient themselves southward, indicating that songbirds' innate sense of direction must be augmented with experience if they are to find their way home.

"This is the first experiment to show that when it comes to songbird migration, age makes a difference," said team member Martin Wikelski, an associate professor of ecology and evolutionary biology. "The results indicate that the adult birds possess a navigational map that encompasses at least the continental U.S., and possibly the entire globe."

Two longstanding questions about migrant songbirds are how quickly they recover when thrown off course -- as they can be when they encounter powerful winds -- and just what navigational tools they use to do so. To address the two questions, the team decided to fit a group of white-crowned sparrows with tiny radio transmitters no heavier than a paper clip and track their movements from a small plane.

The team first brought 30 sparrows to Princeton from northern Washington state, where the birds had been in the process of migrating southward from their summer breeding grounds in Alaska. Half the birds were juveniles of about three months in age that had never migrated before, while the other half were adults that had made the round trip to their wintering site in the southwestern United States at least once.

After the birds were released, they attempted to resume their migration, but both age groups grew disoriented quickly.

"All the birds scattered at first," Wikelski said. "It was clear they were turned around for a couple of days. But while the adults eventually realized they had to head southwest, the younger birds resumed flying straight southward as though they were still in Washington."

The adults, said team member Richard Holland, recovered their bearings because they possess something the younger birds do not, which is an internal map.

"These birds need two things to know where they are and migrate effectively: a 'map' and a 'compass,'" said Holland, a postdoctoral research associate in Wikelski's lab. "What we've found is that juveniles use their compass, but the adults also use their map."

Holland said the birds do not lose the compass as they age, but somehow develop the map, eventually applying both tools to keep on track during migratory flights. Scientists already have determined that the compass is based on the sun or the magnetic field, but where the map comes from remains a mystery -- one that the team will be exploring in coming years.

"It could be the map also derives from the planet's magnetic field," Holland said. "But there are so many local magnetic anomalies in the Earth's crust that it's also possible they are navigating by sense of smell. It sounds crazy, but there's a lot of evidence that homing pigeons navigate this way, so we need to investigate that idea further."

Community
Email This Article
Comment On This Article

Related Links
Princeton University
Darwin Today At TerraDaily.com




Tempur-Pedic Mattress Comparison

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
Scientists Find Risk Distribution Law For Evolution
New York NY (SPX) Nov 06, 2007
Taking a chance on an experiment - this is one of the impulses that drive evolution. Living cells are, from this angle, great subjects for experimentation: Changes in one molecule can have all sorts of interesting consequences for many other molecules in the cell. Such experiments on genes and proteins have led the cell, and indeed all life, on a long and fascinating evolutionary journey.

.
Get Our Free Newsletters Via Email
  



  • China work, road accidents kill nearly 80,000 since January
  • Anger rises in flood-stricken southern Mexico
  • Hungry Mexico flood victims turn to looting
  • Triage Study Challenges Notions of Emergency Medical Response To Disaster

  • Climate controversy heats up Australian election
  • Drought in southeast US fuels battle over water resources
  • White House defends 'health benefits' of climate change
  • Like It Or Not, Uncertainty And Climate Change Go Hand-In-Hand

  • Vacation Photos Create 3D Models Of World Landmarks
  • NASA Data May Help Improve Estimates Of A Hurricane's Punch
  • DMCii Satellite Imaging Helps Dramatically Reduce Deforestation Of Amazon Basin
  • NASA Views Southern California Fires And Winds

  • EU debates common energy strategy
  • Progress Energy Carolinas Seeks Renewable Energy Proposals
  • Trina Solar Named Fastest-Growing Company In Deloitte Technology Fast 50 China 2007
  • ASU Launches Renewable Biofuel Research Initiative

  • NASA Technology Helps Predict And Prevent Future Pandemic Outbreaks
  • Deadly HIV-TB co-epidemic sweeps sub-Saharan Africa: report
  • Northwestern Exposing Most Deadly Infectious Diseases In 3D
  • Staph-Killing Properties Of Clay Investigated

  • For Migrating Sparrows, Kids Have A Compass, But Adults Have The Map
  • Scientists Find Risk Distribution Law For Evolution
  • Earliest Birds Acted More Like Turkeys Than Common Cuckoos
  • Divers Find New Species In Aleutians

  • Toxic smog threatens Indian capital after six-year break
  • Massive pollution in Yangtze river can be reversed: scientists
  • Cairo tries to escape life under a black cloud
  • US Faces Burning Emissions Issue

  • One-child Chinese families prefer it that way
  • Key To False Memories Uncovered
  • Computers Learn Art Appreciation
  • Research Project May Revolutionize Apparel Industry

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2007 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement