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.
The scientists conducted the study in spring 2016 to focus on the spring migration of the willow warbler, 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 landscape, 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 willow warblers.
Forest Research and Natural England collaborated with Stirling on the research, Context-dependent colonisation of terrestrial habitat ‘islands’ by a long-distance migrant bird, which is published in Proceedings of the Royal Society B: Biological Sciences.
Dr Whytock was funded by the IAPETUS Doctoral Training Partnership via the Natural Environment Research Council, the National Forest Company and Forest Research.
The WrEN project is funded by the University of Stirling, Natural England, Forestry Commission, Scottish Natural Heritage, the Department for the Environment, Food and Rural Affairs, the National Forest Company, Forest Research, the Woodland Trust and Tarmac Ltd.