According to recent research from the University of East Anglia, migratory bird populations are dropping globally as a result of how people have changed the landscape. The greatest biological settings and habitats for feeding, reproducing, and rearing their young can be found by migrating birds over distances of hundreds or even thousands of kilometers.
When breeding places experience unfavorable conditions, it is time to migrate to areas with better weather. According to a recent study that was just released, animals that relocate to places with more human infrastructure, such as roads, buildings, electricity lines, and wind turbines, as well as higher population densities and hunting levels, have had the highest population decreases.
Long-term reductions have also been fueled by habitat degradation and climate change. Migration is a tremendous endurance test that demands enormous strength and stamina.
However, modern human activity poses new dangers to birds. Millions of birds are unlawfully murdered by hunters each year, or they clash with man-made objects like powerlines.
Additionally, habitats are shifting or disappearing because to climate change. The research team hopes that their findings may contribute to better conservation effort targeting.
Dr. James Gilroy, from UEA’s School of Environmental Sciences, said:
“We know that migratory birds are in greater decline than non-migratory species, but it’s not clear why. We wanted to find out where in their life cycles these migratory species are most exposed to human impacts.”
One of the biggest impacts seems to be caused by things that would kill a bird outright for example flying into a wind turbine, a building, being electrocuted on a powerline, hit by a vehicle, or hunted. We found that exposure to these human-induced ‘direct mortality’ threats in the bird’s wintering ranges are reflected in population decreases in breeding birds.
Dr. C,laire Buchan
16 human-caused hazards to migrating birds were identified by the research team. These concerns include infrastructure that disturbs and collides with birds, land conversion from natural habitat to human land use, and climate change.
The researchers was able to map each of the 16 hazards across Europe, Africa, and Western Asia because to advancements in satellite imaging. The group also produced the first-ever comprehensive map of the area’s hunting pressure.
Long-distance migratory patterns have significantly more complicated origins than short-distance migration patterns, which likely arose from a very straightforward need for food. They have evolved over many years and are, at least in part, influenced by the genetics of the birds.
They also take into account reactions to the environment, geography, food availability, length of day, and other elements. We used large-scale datasets to study 103 species of migratory birds, including many species that are in fast decline, such as the Turtle Dove and the Common Cuckoo.
For issues like habitat loss and climate change, the scientists estimated “danger scores” for breeding and non-breeding areas. After that, they looked at how these threat levels correlated with trends in bird populations as determined by the Pan-European Common Bird Monitoring Scheme (PECBMS) between 1985 and 2018.
Birds that migrate have the ideal anatomy and physiology for flying quickly and far. They frequently have a difficult trip where they push themselves to the maximum.
Dr. C,laire Buchan from UEA’s School of Biological Sciences, said:
“We found that human modification of the landscape in the birds’ distribution ranges in Europe, Africa, and Western Asia is associated with declining numbers of over 100 Afro-Eurasian migratory birds. When we talk about modification of the landscape, we mean things like roads, buildings, powerlines, wind turbines anything that isn’t naturally there.”
“One of the biggest impacts seems to be caused by things that would kill a bird outright for example flying into a wind turbine, a building, being electrocuted on a powerline, hit by a vehicle, or hunted. We found that exposure to these human-induced ‘direct mortality’ threats in the bird’s wintering ranges are reflected in population decreases in breeding birds.”
Dr. Aldina Franco, also from UEA’s School of Environmental Sciences, said:
“Our findings are important because we need to understand where declining species are being most impacted by humans across their seasonal migrations. Pinpointing where birds are most exposed to these threats could help us target conservation actions.”
The University of East Anglia (UK) served as the project’s principal investigator, working with the Universities of Porto and Lisbon (both in Portugal) and the Czech Society for Ornithology (Czech Republic).
The Natural Environment Research Council (NERC), the European Commission, and the Portuguese Foundation for Science and Technology have all provided money to researchers working on this study.
