Scientists warn that migratory birds are spending more time in Europe, raising worries about whether some may cease migrating completely in the winter.
According to Durham University research, trans-Saharan flyers are spending up to 60 days more per year in European breeding grounds than they were previously, potentially as a result of climate change. The researchers looked at data from Gambia and Gibraltar dating back 50 years. Nightingales, willow warblers, and a variety of wagtails are among the species that have been impacted.
Ornithologists in The Gambia between 1964 and 2019 and The Gibraltar Ornithological and Natural History Society between 1991 and 2018 collected data for the study, which was published in the journal Global Change Biology. The scientists analyzed and discovered that species were arriving at their winter destinations later in the fall and abandoning these sites earlier in the spring, lowering the amount of time spent in their winter homes. Migratory birds such as reed warblers, northern wheatears, and common whitethroats increased their stay in Europe by 16 days on average over 27 years. While it was previously considered that birds planned migration based on day length, the study’s findings imply that birds are making “more sophisticated judgments” in response to factors such as “changes in climate and available vegetation,” according to a university spokesman.
Many of these little migratory birds are experiencing major population reductions in the United Kingdom, with nightingales facing extinction and breeding willow warblers in England down by 45 percent in the last 24 years. However, populations of chiffchaffs, a short-distance migratory that spends the winter in Europe or North Africa, have surged by 114% in the same period.
“If the trends we’ve seen in this study continue, we may see certain birds spend no time at all in Sub-Saharan Africa, and instead spend the whole year in Europe,” said lead author Kieran Lawrence of Durham’s department of biosciences. “Meanwhile, in the traditional migration destinations of sub-Saharan Africa, a reduction in the time migratory birds spend there could have implications for ecosystem services such as insect consumption, seed dispersal, and pollination.”
“We are already witnessing changes in migratory patterns, which might lead to prolonged breeding seasons for some species, as well as knock-on impacts on other species, both here in the UK and typical winter migration destinations.” If the birds do not migrate, he believes there would be more competition for food in Europe throughout the winter and fall. Meanwhile, the extinction of African birds would have “ecosystem ramifications” in terms of insect intake, dispersion speed, and pollination.
Professor Stephen Willis, the project’s leader, said his team will create a new model to predict migrations and future situations.
By kesiya kattukkaran