Diverse migration helps birds cope with environmental change

January 25, 2016

Migratory birds that are 'set in their ways' could be more vulnerable to environmental impacts - according to new research from the University of East Anglia (UEA).

Many species of migratory birds are in decline as a result of human impacts such as climate change and habitat loss.

New research published today reveals why some species are more vulnerable than others.

It shows that species that migrate to a more diverse range of winter locations during their non-breeding season - such as White Storks, Marsh Harriers and Reed Warblers - are less likely to suffer population decline.

However species that tend to 'funnel' into smaller areas during the winter - such as Turtle Doves and Wood Warblers - have been more vulnerable to declining numbers, caused by human impacts.

Lead researcher Dr James Gilroy from UEA's School of Environmental Sciences said: "Birds are well-known for their remarkable long-distance migrations, often involving extreme feats of navigation and endurance. Unfortunately, many migratory birds are in decline, and there is an urgent need to understand what determines their vulnerability to human impacts.

"We wanted to know whether 'migratory diversity' - the variability of migratory behaviour within species - plays a role in determining their population trends."

The research team studied the migration patterns of 340 bird species in relation to their status across Europe over the last two decades (1990-2012).

Dr Gilroy said: "We found that the species which scatter across wider areas in the non-breeding season have been more resilient, whereas those that converge along narrower routes, and hence occupy smaller wintering areas, have been more likely to decline.

"This suggests that these species may be particularly vulnerable to impacts like habitat loss and hunting in their non-breeding ranges. Species that spread across wider wintering areas, by contrast, might have a greater chance of reaching safe habitats in at least some parts of their range."

The research team also found that species classed as 'partial migrants' - meaning that their populations include both migratory individuals and others that remain in the breeding area all year round - were less likely to decline than fully migratory species, or even those that are fully resident.

Dr Gilroy said: "Many species adopt this mixed migratory strategy, including familiar species like Blackbirds and Robins. It looks like it could make them more resilient to human impacts - even in comparison to species that don't migrate at all. Many fully resident species like Lesser-spotted Woodpeckers and Willow Tits have been showing worrying declines in recent years.

"Partially migratory species also showed a greater capacity to shift their spring arrival dates forwards in recent decades, relative to fully migratory species. This trend towards earlier spring arrival might help species adapt to climate change, by allowing them to commence breeding earlier in the year as spring temperatures rise."

Co-author Dr Aldina Franco, also from UEA's School of Environmental Sciences, said: "The fact that migratory birds are declining globally has been troubling both scientific and conservation communities.

"We hope that this research will help relevant authorities identify ways to protect the long-distance migratory species that occupy small wintering areas. These are more likely to suffer population declines and need specific conservation efforts. Species with low migratory dispersion for example would benefit from a focus on conservation within their winter locations."

This research was funded by the Natural Environment Research Council (NERC) and is part of a project to investigate the causes and consequences of partial migration on birds. A high quality video about the project is available here: https://vimeo.com/151900214

'Migratory diversity predicts population declines in birds' is published in the journal Ecology Letters on January 26, 2016.

University of East Anglia

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.