Migration: How Birds React to Climate Change Paints a Picture for People

Two adult northern spotted owls on a moss covered tree branch

NPS / Taylor Ellis

Have you ever heard of the canary in the coalmine? Miners used to carry caged canaries, a type of bird, into a coalmine to test for the presence of dangerous gases. The gases would kill the bird before the miners, giving them a warning to get out of harm’s way.

While Muir Woods doesn’t contain coalmines, birds and other wildlife are still a good indicator for the health of our ecosystem. Climate change impacts this ecosystem. When people burn fossil fuels, like coal, oil, or natural gas for our energy needs, we release carbon dioxide into the Earth’s atmosphere. That carbon dioxide naturally acts like a blanket that traps heat. The more fossil fuels we burn, the thicker that blanket gets, which disturbs the climate both here at Muir Woods and throughout the world.

Like the canaries in the coalmines, birds are sensitive to environmental changes around them. They also are easy to identify and count, so there’s a wealth of data about where they live and their abundance. For this reason, scientists and park staff can focus on shifts in bird populations as a way to monitor the changing ecosystem. Flowers may bloom earlier, warmer temperatures will allow new diseases to move in, water availability will decrease, and more. All of these changes are affecting the routine birds have been following for thousands of years. While animals can adapt to slow, gradual changes over time, these changes are happening suddenly. By mid-century, these changes will already be taking place. Some birds that currently live in the forest will continue to call Muir Woods home. Others that live here now, such as the spotted owl, may find this habitat unsuitable and need to migrate away. Species of birds that have fled from other habitats may begin to call Muir Woods home in the future as they migrate due to a changing climate. Changing conditions may extirpate, or cause a local extinction of certain birds species at Muir Woods, and make the habitat worse for others. The extent to which birds will be affected is based on the amount of fossil fuels we burn. The more we burn fossil fuels, the more the climate will change, and the more it will impact birds and other species.

Birds aren’t alone in the changes climate change will bring. All animals, people included, will have to move or adapt when climate change impacts their home. Where some people can go inside and turn on the AC during hot days, other animals are more at risk as the frequency of unusually hot days increases. Species such as bumblebees have been facing local extinction events and decreasing in biodiversity.

The Intergovernmental Panel on Climate Change (IPCC) has said that the “greatest single impact of climate change might be on human migration—with millions of people displaced by shoreline erosion, coastal flooding and agricultural disruption”. Like the animals at Muir Woods facing extreme weather events, people will be forced to move, change, and adapt.

However, unlike the animals in Muir Woods, people can see the pattern of these changes happening around us, and do something to stop it. That’s why, at Muir Woods, we’re getting 100% of our energy from renewable resources like solar and wind. These clean energy sources decrease the amount of CO2 we release into the atmosphere, which helps mitigate climate change. What can you do with your community to help the animals at Muir Woods, your local wildlife and people around the world?

For more information

• Oli Brown. "Migration and Climate Change" IOM Migration Research Series, International Organization for Migration, 2008.
• Soyre et al. “Climate change contributes to widespread declines among bumble bees across continent”. Science, 2020.
• Wu et al. “Projected avifaunal responses to climate change across the U.S. National Park System.” PLOS ONE, 2018.