Global warming may cause birds to cancel their migrations

Retired people who choose to spend the winter months in warmer climates are often referred to as “snowbirds.” However, if your vacation home was only a bit warmer than your regular home, would you make the effort to move for half of the year? Some migratory birds are apparently deciding that they’d rather stick just around at home, according to a new study from Durham University. 

The researchers looked at data ranging from 1964 to 2019, examining a variety of different migratory bird species. These observations showed that over time, some species were spending up to sixty more days in northern latitudes each year. 

“If the trends we have seen in this study continue we may see that, in time, some birds will spend no time at all in sub-Saharan Africa, and instead spend the full year within Europe,” said study lead author Kieran Lawrence.

“The changes in migratory habits we are already seeing could lead to longer breeding seasons for these species, as well as knock-on effects on other species, both here in the UK and in the traditional winter migration destinations.”

More than simply giving Europeans that much longer to birdwatch, this change in behavior could lead to some serious environmental consequences. If more species crowd the skies during the winter months, competition for resources could increase. 

Furthermore, ecosystem services that the birds provide on the other side of the equator would be absent. This means less insects are eaten and less pollination occurs – bad news for habitats that are already vulnerable to fluctuations in climate. 

Animals must adapt to the changing conditions or face extinction. As global warming continues, behavioral changes like this will likely become all too common. 

“Next, we aim to apply a new model, which we are developing at Durham, to simulate these complex migrations, and which we can then apply to future scenarios to understand how the patterns we have identified in trans-Saharan birds over recent decades may continue or change,” said Professor Stephen Willis, who led the project.

Study co-author Clive Barlow, a resident of the west African country The Gambia, is an expert on the birds of this region. 

“It is very satisfying to see the constructive way the Gambian migrant bird records, collected by dedicated ornithologists over many decades, are now being used to highlight the changing migratory patterns of these species,” said Barlow.

“Until the current research, no-one had realized the extent to which migrant birds are spending less of the year in sub-Saharan Africa.”

The study is published in the journal Global Change Biology.

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By Alex Ruger, Earth.com Staff Writer