Many species are already spending up to an extra two months in their summer breeding grounds already, a team of researchers led from Durham University found.
They came to this conclusion after studying more than 50 years of trans-Saharan migratory bird sightings from both Gibraltar and The Gambia.
Among the affected species are some of Europe’s most common migratory birds — including Nightingales and Willow Warblers.
The team’s data suggest that these birds are able to survive longer in their European breeding grounds than before and may one day not need to migrate at all.
The findings show that birds are not just timing their migrations based on day length, but make nuanced decisions factoring in 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.
The winter migration of birds southwards from Europe to Africa may become a thing of the past thanks to the impacts of climate change, a study has warned. Pictured: the common nightingale, one of the many species whose migrations are already changing schedules
‘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 paper author and Durham University ecologist 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.
‘In Europe, the longer presence of traditionally migratory birds could lead to increased competition for autumn/winter food and resources for resident bird species that do not migrate.
‘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.’
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.
From this, the team assessed changes in migratory bird arrival and departure dates over time, comparing this with observed climate and vegetation changes.
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.
‘Next, we aim to apply a new model, which we are developing at Durham, to simulate these complex migrations,’ added lead author and Durham University bioscientist Stephen Willis.
This model, he explained, could be applied ‘to future scenarios to understand how the patterns we have identified in trans-Saharan birds over recent decades may continue or change.’
Many species are already spending up to an extra two months in their summer breeding grounds already, a team of researchers led from Durham University found. Pictured: a white wagtail, one of the migratory birds that the researchers assessed in their study
The researchers studied more than 50 years of trans-Saharan migratory bird sightings from both Gibraltar and The Gambia
The team’s data suggest that birds like the northern wheatear (pictured) are able to survive longer in their European breeding grounds than before and may one day not need 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
‘Until the current research, no-one had realised the extent to which migrant birds are spending less of the year in sub-Saharan Africa,’ he added.
The full findings of the study were published in the journal Global Change Biology.
The findings show that birds like the yellow wagtail, pictured, are not just timing their migrations based on day length, but make nuanced decisions factoring in climate and vegetation availability
WHY DO MIGRATING BIRDS FLY IN A V-FORMATION?
Birds fly in a v-formation to help them fly more efficiently, staying aloft while expending as little energy as possible.
Scientists learned the aviation secrets of migrating birds after attaching tiny logging devices to a flock of 14 northern bald ibises that not only tracked their position and speed by satellite but measured every flap of their wings.
The 14 birds used in the study were hand-reared at Vienna Zoo in Austria by the Waldrappteam, an Austrian conservation group that is re-introducing northern bald ibeses to Europe.
Birds fly in a v-formation to help them fly more efficiently, staying aloft while expending as little energy as possible (stock image)
The birds were studied as they flew alongside a microlight on their migration route from Austria to their winter home in Tuscany, Italy.
Lead researcher Dr Steve Portugal, from the Royal Veterinary College, University of London, said: ‘The distinctive V-formation of bird flocks has long intrigued researchers and continues to attract both scientific and popular attention, however a definitive account of the aerodynamic implications of these formations has remained elusive until now.
‘The intricate mechanisms involved in V-formation flight indicate remarkable awareness and ability of birds to respond to the wingpath of nearby flock-mates. Birds in V-formation seem to have developed complex phasing strategies to cope with the dynamic wakes produced by flapping wings.’
When flying in a V formation, the birds’ wing flaps were approximately ‘in-phase’, meaning all the wing tips followed roughly the same path, the scientists found.
This helped each bird capture extra lift from the upwash of its neighbour in front.
Occasional shifts of position within the formation meant that at times birds flew directly one behind the other.
When this happened, the birds altered their wing beats to an out-of-phase pattern to avoid being caught by downwash.