Migratory birds track climate throughout the year

Yellow warblers are found throughout North America and fly to Central and South America for winter. Rachael Bay, assistant professor of evolution and ecology at UC Davis, and colleagues found that individual birds show preferences for drier or wetter environments throughout the year and that this preference can be predicted by their genetics. Credit: Jonathan Eisen

As climate change takes hold across the Americas, some areas will warm up, and others will heat up and become drier. A new study of the yellow warbler, a widespread migratory songbird, shows that individuals have the same climate preferences throughout their migratory range. The work is published on February 17 in Ecological Letters.

“What’s amazing is that the birds track similar climates despite migrating thousands of miles,” said Rachael Bay, an assistant professor in the Department of Development and Ecology, College of Biological Sciences at the University of California, Davis. “It seems that individual birds can be adapted to particular climatic regimes.”

Yellow warblers (Setophagia petechia) breed throughout North America and fly south to Central and South America to spend the winter. A previous study by Bay and colleagues found links between genetic variation and precipitation across North America, suggesting that some individuals might be adapted to dry conditions while others thrive in wet conditions. In the current study, the authors were able to use genetics to predict where birds caught on their wintering grounds in Central and South America will end up breeding and compare climate patterns in their wintering and summer regions.

Individual birds showed preferences for drier or wetter areas, but not for warmer or colder areas. In other words, birds that have bred in relatively dry parts of North America – such as the Central California Valley – have wintered in dry parts of South or Mesoamerica.

“This is the first demonstration of using individual genetic tracking to link climates through the migration cycle within a bird species,” Bay said.

Migratory birds track climate throughout the year

Yellow warblers are found throughout North America and fly to Central and South America for winter. Rachael Bay, assistant professor of evolution and ecology at UC Davis, and colleagues found that individual birds show preferences for drier or wetter environments throughout the year and that this preference can be predicted by their genetics. Credit: Daniel Karp

Impact of climate change

This range of climate preferences could have consequences on how birds react to climate change. Bay speculates that the variety she and her colleagues found could provide the raw material for the species to adapt to changing climatic conditions. For example, populations adapted to drier conditions could displace those adapted to wetter ones. In fact, Bay and colleagues have already found that population sizes of yellow warblers have changed with precipitation over years.

Bay collected data for the study during her postdoctoral research, in collaboration with band stations and collecting sites in North and South America. Bay and her colleagues now want to see if individuals of other bird species also track climate during migration.


Winter bird communities track climate change faster than breeding communities in Europe and North America


Additional information:
Rachael A. Bay et al, Genetic variation reveals individual-level climatic footprint through the annual cycle of a migratory bird, Ecological Letters First published: 17 February 2021 doi.org/10.1111/ele.13706

Quote: Migratory birds track climate throughout the year (2021, 18 February) taken 18 February 2021 from https://phys.org/news/2021-02-migratory-birds-track-climate-year.html

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