A study has shown that the impacts of climate change could make the winter migration of birds from Europe to Africa a distant memory.
Durham University researchers found that many species spend an additional two months in their summer breeding areas.
After more than 50 years of trans-Saharan bird sightings from Gibraltar and The Gambia, the researchers came to this conclusion.
Among the affected species are some of Europe’s most common migratory birds — including Nightingales and Willow Warblers.
These birds may be able to stay longer in their European breeding grounds and may not require migration, according to the team’s data.
The results show that birds do not simply time their migrations on the basis of day length. They also make nuanced decisions that take into account climate and vegetation availability.
It is estimated that some 4,000 bird species — around 40 per cent of the world’s total — undertake regular migrations.
A study has found that climate change may make it impossible for birds to migrate southwards from Europe towards Africa in winter. This is according to a warning. Pictured: The common nightingale, which is one of many species whose migrations may be changing.
According to Kieran Lawrence, a Durham University ecologist and paper author, “If the trends that we have seen in the study continue, we may find that some birds will spend none of their time in sub-Saharan Africa and instead spend the entire year in Europe.”
‘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.
“In Europe, the longer existence of traditionally migratory birds could lead towards increased competition for autumn/winter foodstuffs and resources for resident bird species who do not migrate.
“Meanwhile in sub-Saharan Africa, a reduction of migratory birds spending there could have implications on ecosystem services such as pollination and seed dispersal.
In their study, Mr Lawrence and colleagues analysed data on local bird sightings collected by ornithologists in The Gambia from 1964–2019 and members of the Gibraltar Ornithological & Natural History Society from 1991–2018.
The team then compared observed climate and vegetation changes with the changes in migratory bird arrivals and departures over time.
The researchers found that birds are arriving at their winter migration destinations later into the Autumn than they were in the past — and also heading back north earlier in the spring.
Stephen Willis, Durham University bioscientist and lead author, said, “Next, we aim to use a new model which we are developing here at Durham to simulate these complex migratings.”
He explained that the model could be applied to future scenarios to understand how patterns in trans-Saharan bird migrations over recent decades might continue or change.
A Durham University research team discovered that many species spend up to two extra months in their summer breeding grounds. Pictured: A whitewagtail, one migratory bird that the researchers assessed during their study.
The researchers analyzed more than 50 years worth of trans-Saharan sightings of migratory birds from Gibraltar and The Gambia.
The team’s data suggests that birds like the northern Wheatear (pictured) can live longer in their European breeding grounds and may not require to migrate.
‘It is very satisfying to see the constructive way the Gambian migrant bird records are now being used to highlight the changing migratory patterns of these species,’ said paper author Clive Barlow of the Birds of The Gambia
He added that “Until the current study, no one had realized how much migrant birds spend less of the year sub-Saharan Africa,”
The study’s full results were published in the journal Global Change Biology.
The findings reveal that birds such as the yellow wagtail (pictured) are not just timing migrations based upon day length but also consider climate and availability of vegetation.
WHY DO MIGRATING BIRDS FLY IN A V FORMATION?
To help birds fly more efficiently, they use a v-formation. This allows them to stay high and expend as little energy as possible.
Scientists discovered the secrets to migrating birds’ flight patterns by attaching tiny logging devices on 14 northern bald Ibises. These devices not only tracked their speed and position via satellite, but also measured every flap of their wings.
The study involved 14 birds that were hand-reared by the Waldrappteam, an Austrian conservation organization that is reintroducing northern bald Ibeses to Europe.
To help birds fly more efficiently, they use as much energy as possible to stay high and fly in a v-formation (stock image).
The birds were observed as they flew with a microlight along their migration route from Austria, to Tuscany, Italy.
Dr Steve Portugal, a Royal Veterinary College, University of London lead researcher, stated: “The distinctive V-formation of bird birds has long intrigued researchers and continues attracting both scientific and popular attention. However, a definitive account of aerodynamic implications of these formations remains elusive until now.
“The intricate mechanisms involved with V-formation flight show remarkable awareness and ability to respond to the wingpaths of nearby flock-mates. The complex phasing strategies of V-formation birds seem to have been developed to deal with the dynamic wakes caused by flapping wings.
Scientists found that the V-shaped birds’ wing flaps were in-phase, which means that all the wing tips followed the same path when flying in V formation.
This allowed each bird to receive extra lift from the upwash of its neighbor in front.
Sometimes birds flew in a straight line, sometimes due to shifts in position within the formation.
The birds then changed their wing beats out of phase to avoid being caught by the downwash.