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Image showing Yellow Wagtail

Experts from our Department of Biosciences think this is a possibility after new research found that some species of trans-Saharan migratory birds, like Nightingales and Willow Warblers, are spending as many as 50-60 fewer days a year in their non-breeding grounds in Africa.

Changing historical patterns

The research was the first to look at how long trans-Saharan migratory birds are spending in their traditional winter retreats in Africa.

Using over 50 years of bird records collated by ornithologists in The Gambia and Gibraltar, our experts explored the arrival and departure dates of migratory birds over time. They also related these observed changes to changes in climate and vegetation.

They found that many of Europe’s most common migratory birds are spending longer in their European breeding-grounds; departing later for sub-Saharan Africa and choosing to return to Europe earlier.

This change suggests that the birds are able to survive longer in their European breeding grounds than before, leading experts to question whether some birds may eventually stop their traditional long-distance migrations.

Nuanced decisions and knock-on effects

It was previously thought that birds timed migration based on day length, however the findings from this study suggest that birds are also making more nuanced decisions, responding to factors such as changes in climate and available vegetation.

Changes in migratory habits could lead to longer breeding seasons for these species, and have knock-on effects on other species, both in the UK and in traditional winter migration destinations.

In Europe, the longer presence of traditionally migratory birds could see more competition for autumn/winter food and resources for resident bird species that do not migrate.

Whilst in the traditional migration destinations of sub-Saharan Africa a reduction in the time migratory birds spend there could have implications for ecosystems such as insect consumption, seed dispersal and pollination.

Modelling the future

Looking ahead the team aim to apply a new model, which is being developed by our bioscientists, to simulate birds’ complex migrations, and apply this to future scenarios to understand how the patterns they have identified in trans-Saharan birds over recent decades might continue or change.

Find out more

  • This paper was authored by PhD student Kieran Lawrence and the project was led by Professor Stephen Willis.
  • Read the full study published in Global Change Biology here.
  • Find out more about undergraduate and postgraduate study in our Department of Biosciences.
  • The work at Gibraltar Bird Observatory was funded by the Gibraltar Ornithology & Natural History Society.
  • Professor Stephen Willis’ work was supported by a grant from the Natural Environment Research Council - NE/T001038/1.