It's not trails that disturb forest birds, but the people on them

Date:  November 12, 2018

Source:  Frontiers

The physical presence of trails has less impact on forest birds than how frequently the trails are used by people, finds the first study to disentangle the effect of forest trails from the presence of humans. This is also the case when trails have been used for decades, suggesting that forest birds do not get used to human activity. To minimize disturbance, people should avoid roaming from designated pathways.

The first study to disentangle the effect of forest trails from the presence of humans shows the number of birds, as well as bird species, is lower when trails are used on a more regular basis. This is also the case when trails have been used for many years, suggesting that forest birds do not get used to this recreational activity. Published in Frontiers in Ecology and Evolution, the finding suggests the physical presence of trails has less of an impact on forest birds than how frequently these recreational paths are used by people. To minimize the impact on these forest creatures, people should avoid roaming from designated pathways.

"We show that forest birds are quite distinctly affected by people and that this avoidance behavior did not disappear even after years of use by humans. This suggests not all birds habituate to humans and that a long-lasting effect remains," says Dr Yves Bötsch, lead author of this study, based at the Swiss Ornithological Institute, Sempach, Switzerland and affiliated with Institute of Evolutionary Biology and Environmental Studies, University Zurich, Switzerland. "This is important to show because pressure on natural habitats and nature protection areas is getting stronger and access bans are often ignored."

Many outdoor activities rely on infrastructure, with roads and trails being most common. Previous research has shown that trails cause habitat loss and fragmentation, where larger areas of habitat are dissected into smaller pieces thereby separating wildlife populations. However it has been difficult to say for certain whether it is the presence of trails or humans that have the most impact on forest birds.

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Long-term study reveals one invasive insect can change a forest bird community

Date:  May 23, 2018

Source:  American Ornithological Society Publications Office

Eastern hemlock forests have been declining due to a non-native insect pest, the hemlock woolly adelgid. A new study from The Condor: Ornithological Applications presents some of the best long-term data showing how the decline of a single tree species (eastern hemlock) leads to the disappearance of birds specialized to those trees. The data also indicate birds associated with non-hemlock habitat features (deciduous forest, woodland edge, and shrubs) are spreading into former hemlock forests. A single insect species has led to a less diverse bird community across this landscape.

Pennsylvania State University's Matthew Toenies and colleagues analyzed a long-term response to the decline of eastern hemlocks using vegetation and bird abundance surveys. The researchers took advantage of surveys they had conducted in 2000 before adelgids had caused hemlock decline and compared those data to new data from the same forests in 2015-16, after decline. They then analyzed how both individual bird species and groups of species responded to this habitat change.

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Forest bird population crashes

By John Myers on Jan 2, 2015 at 7:00 p.m.

DULUTH, Minn. — The number of birds counted each summer on Minnesota’s Chippewa and Superior National Forests nearly doubled from 1994 to 2009 but crashed by 30 percent this year after back-to-back cold, late springs.

And the legacy of this year’s poor nesting season could last into next year, with fewer chicks hatched this summer and even fewer birds returning to be counted in 2015.

That’s the conclusion of the annual Summary of Breeding Bird Trends released recently by researchers at the Natural Resources Research Institute of the University of Minnesota Duluth.

The number of total birds counted in the survey, now in its 20th season, has moved up and down in fits and spurts but has trended up over the long haul.

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