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."
|Contact: Chad Boutin|