Shifting ranges is one of the most common strategies species use to cope with climate change. As temperatures rise, many animals move northward or upward in elevation in search of cooler conditions. For some species, this movement depends on the presence of climate corridors that connect fragmented habitats. Others, such as birds, are highly mobile and often assumed to be better equipped to adjust their ranges in response to changing climates.
Cohen, J.M. and Jetz, W. 2025. Geographic redistributions are insufficient to mitigate exposure to climate change in North American birds. Nature Ecology & Evolution 9: 1234-1244.
Much of the existing research has focused on predicting where species are likely to move, but far less is known about how effective these shifts are at reducing exposure to warming. Measuring the difference between the temperatures species actually experience after moving versus those they would have faced if they had remained provides valuable insight into whether range shifts effectively offer climate relief. This approach helps determine the extent to which redistribution can serve as a successful climate adaptation strategy.
A new study tackles this question by examining more than 20 years of data for over 400 bird species in the United States and Canada, taken from millions of citizen science and survey records. By carefully accounting for biases in where and when observations were made, researchers measured how much birds had shifted their ranges and whether those movements actually helped them maintain their historical climate niches.
On average, birds shifted their summer ranges north by about 0.64° of latitude, avoiding roughly half of the warming they would have experienced if they hadn’t moved. Even so, most species still experienced more than 1 °C of warming in just two decades.
Winter range shifts were even less effective at reducing exposure. Despite similar northward shifts, species were only able to offset about 11% of expected warming, with nearly all species exposed to temperature increases of greater than 2 °C. Birds that were capable of moving longer distances and that had traits correlating to longer dispersal fared better, while less mobile or habitat-restricted species struggled to keep pace.
These findings underscore an important reality for conservation. Even among birds, which are relatively mobile compared to other taxa, climate change is eroding environmental niches faster than species can shift their ranges. Landscape connectivity and intact corridors remain critical tools for enabling movement, but they may not be enough on their own. Habitat fragmentation, limited availability of suitable cover, and the accelerating rate of climate change all constrain the effectiveness of range shifts as a strategy for persistence.
For wildlife managers and conservation planners, the message is twofold. First, maintaining and expanding habitat connectivity will continue to be essential for allowing species the best chance to adjust. Corridors and connected landscapes can help birds and other wildlife navigate toward more suitable climates while avoiding fragmented or degraded areas. Second, connectivity needs to be paired with strategies that reduce emissions and consider other adaptive responses, such as protecting microhabitats and conserving climate refugia.
This study highlights both the promise and the limits of redistribution as a climate adaptation strategy. If even birds cannot fully track their preferred climates, other less mobile species may face even greater risks. Conservation efforts that integrate connectivity with broader climate mitigation and adaptation planning will be key to supporting biodiversity in the future.
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