A study led by Nebraska's Robert Zink proposes that many bird species, such as the Canada warbler, may have completely stopped migrating during the last ice age.
The onset of the last ice age may have forced some bird species to abandon their northerly migrations for thousands of years, says new research led by a University of Nebraska-Lincoln ornithologist.
Published Sept. 20 in the journal Science Advances, the study challenges a long-held presumption that birds merely shortened their migratory flights when glaciers advanced south to cover much of North America and northern Europe about 21,000 years ago.
The study concluded that the emergence of glaciers in those regions instead acted as an “adaptive switch” that turned off migratory behavior, transforming the tropics from a cold-weather resort into a long-term residence for certain bird species.
Of the 29 long-distance migrant species examined in the study, 20 likely saw their northern breeding grounds become uninhabitable, according to models developed by the researchers. When the climate again warmed and glaciers retreated back to the Arctic, those species presumably resumed their seasonal migrations.
Lead author Robert Zink said the conclusions could alter how scientists reconstruct the history of bird migration.
“It fundamentally changes the way we study the evolution of migration and think about the migratory behavior of birds,” said Zink, professor of natural resources and biological sciences at Nebraska.