Birds Tell Us Both Climate Action and Healthy Natural Spaces Are Key to a Secure Future

A new study uses 90 years of Christmas Bird Count data to show how birds have shifted amid a century of major environmental changes.

NEW YORK  - This month, scientists at the National Audubon Society published a study that analyzed how birds of the eastern United States have responded due to climate change and habitat availability in the last 90 years. Published in Global Change Biology, researchers determined that winter ranges of all birds have moved in response to climate change, and that bird species with specific habitat needs (e.g. grasslands or wetlands) are even more restricted by habitat availability in where they can exist in a climate-altered future. Few studies have yet to analyze how climate change and habitat suitability are linked with respect to bird populations, but the longevity of Audubon's Christmas Bird Count data set allowed Audubon researchers to explore this connection, with important implications for wildlife conservation efforts in the future. 

"Birds tell us that climate change is already having an effect on them, but not all birds are equally vulnerable to climate change,” said Sarah Saunders, PhD, primary author of the study and quantitative ecologist at Audubon. “If we want to give birds the best chance at survival, habitat conservation needs to be part of our efforts to fight climate change. We can still secure a future for birds and people, but the science is clear: we need to act on climate now.” 

In order to interpret more than 90 years of Christmas Bird Count observations from 119 different count circles in the eastern United States, the Audubon researchers sorted 89 species of birds into the following groups: large forest birds, forest passerines, grassland birds, mixed-habitat birds, waterbirds, shrubland birds, waterfowl, wetland passerines, and woodpeckers. Results showed that climate-related changes in temperature and precipitation impacted the winter ranges for all groups of birds. For example, large forest birds and woodpeckers are now wintering further north than before. However, while habitat-restricted birds like waterfowl, wetland birds and grassland birds are also responding to climate change, they are only spending the winter where there is suitable habitat remaining. Gaining a deeper understanding of how different species respond to climate change versus habitat change can better inform conservation efforts. 

“This study confirms that protecting birds from climate change in the future needs to go hand-in-hand with protecting healthy natural spaces that birds need right now,” said Marshall Johnson, chief conservation officer for Audubon.  

Climate change threatens more than two-thirds of North America’s bird species with extinction, according to Audubon’s 2019 report Survival By Degrees: 389 Species on the Brink. However, the same science suggests that by limiting global warming to 1.5 degrees Celsius, more than three-quarters of vulnerable species can be protected. Audubon supports efforts to reach net-zero carbon pollution by 2050. 

“This important new study is just the latest example of peer-reviewed research made possible by more than twelve decades' worth of Christmas Bird Count data,” said Geoff LeBaron, Director of Audubon’s Christmas Bird Count. “Every bird tallied (or not) tells us a little more about the state of our environment, and we are grateful to all Christmas Bird Count participants and compilers who help us protect birds and the places they need, today and tomorrow.” 

This was the first time that Audubon scientists had analyzed up to 90 years of Christmas Bird Count data. The Audubon CBC is a community science project organized by the National Audubon Society. There is no fee to participate.  

In addition to the Christmas Bird Count, Audubon invites members and supporters to participate in next month’s Great Backyard Bird Count. Learn more about this worldwide community science project here:  

The National Audubon Society protects birds and the places they need, today and tomorrow, throughout the Americas using science, advocacy, education and on-the-ground conservation. Audubon’s state programs, nature centers, chapters and partners have an unparalleled wingspan that reaches millions of people each year to inform, inspire and unite diverse communities in conservation action. Since 1905, Audubon’s vision has been a world in which people and wildlife thrive. Audubon is a nonprofit conservation organization. Learn more at and @audubonsociety. 

Media Contacts: Nicolas Gonzalez,, (310) 897-9836.