Study reveals impact of habitat fragmentation on migrant birds

September 6, 2018, University of Stirling
Robin Whytock Credit: University of Stirling

Experts at the University of Stirling have shed new light on the impact of habitat fragmentation on migrant birds.

Scientists used audio technology to analyse the behaviour of willow warblers, after spring migration, in 23 woodland patches across Scotland and England. While the patches were of a similar size, the landscapes in which they were located had differing amounts of available .

Significantly, the study found that migrant male willow warblers arrived earlier in woodland patches when there was less habitat in the surrounding landscape, within a 2km radius.

The team also found that an individual's decision to remain in a after initial colonisation depended on patch quality, as measured by vegetation characteristics. In particular, birds preferred to stay in woodlands with a relatively open understorey, also known as undergrowth.

Robin Whytock, of the Faculty of Natural Sciences, led the work as part of his Ph.D. alongside colleagues at the University, Professor Kirsty Park, Dr. Elisa Fuentes-Montemayor and co-supervisor Dr. Kevin Watts at Forest Research.

"Habitat fragmentation and loss has changed how animals move through landscapes and use the remaining habitat," Dr. Whytock said. "Whether an animal colonises a fragmented habitat patch—for example, a small woodland—depends on a variety of factors, including the content of the surrounding landscape and the quality of the patch itself.

"This study gives a valuable insight into how affects the behaviour of even very mobile species, such as .

"Our results support prior research in aquatic study systems that have looked at colonisation of artificial reefs and ponds—and, as far as we know, this is the first time that the patterns observed in our study have been observed over such large spatial scales and with such a highly mobile species."

The scientists conducted the study in spring 2016 to focus on the spring migration of the willow , which migrates bi-annually between northern Europe and sub-Saharan Africa.

They combined the latest bio-acoustic technology—which recorded the first song dates of male willow warblers—with Stirling's unique Woodland Creation and Ecological Networks (WrEN) project to test how the amount of habitat in a regional landscape affects colonisation timing of isolated woodland patches.

On analysing the audio data, the team found first song dates were on average five days earlier in patches with five percent woodland cover in the , when compared to patches with around 30 percent cover.

Dr. Whytock added: "These findings are particularly interesting when you consider that previous research has suggested this species benefits from large expanses of woodland during migration. Therefore, it's surprising that individuals should choose to settle earlier in isolated woodlands."

He said further work is now required to examine whether this has consequences for the survival and reproduction of warblers.

Explore further: Improving habitats for bats

More information: Robin C. Whytock et al, Context-dependent colonization of terrestrial habitat 'islands' by a long-distance migrant bird, Proceedings of the Royal Society B: Biological Sciences (2018). DOI: 10.1098/rspb.2018.1490

Related Stories

Improving habitats for bats

July 31, 2017

The effects of 160 years of woodland creation on bats has been revealed by a natural experiment.

Major new project maps out woodland biodiversity

April 5, 2016

An innovative joint project between the University of Stirling, Forest Research and Natural England is using woodland creation and maps from 1840 to the present day to assess the impact of past land use change on current ...

Birds' migration genes are conditioned by geography

July 6, 2017

The genetic make-up of a willow warbler determines where it will migrate when winter comes. Studies of willow warblers in Sweden, Finland and the Baltic States show that "migration genes" differ - depending on where the birds ...

Recommended for you

Discovery could neutralize West Nile virus

November 20, 2018

Researchers at Vanderbilt University Medical Center and colleagues have isolated a human monoclonal antibody that can "neutralize" the West Nile virus and potentially prevent a leading cause of viral encephalitis (brain inflammation) ...

The taming of the dog, cow, horse, pig and rabbit

November 20, 2018

Research at the Earlham Institute into one of the 'genetic orchestra conductors', microRNAs, sheds light on our selectively guided evolution of domestic pets and farmyard animals such as dogs and cows.

A Mexican cavefish with a scarred heart

November 20, 2018

Scientists are studying a guppy-sized, blind, translucent fish that lives in the cave systems of northern Mexico to figure out why some animals can regenerate their hearts, while others just scar. Their research appears November ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.