Climate Change Resistance: How Local Adaptation Benefits Certain Bird Species

The North American song sparrows exhibit an intriguing adaptation that could enhance their resilience to climate change: a diverse array of body sizes across their westernmost habitat.

APA 7: TWs Editor & ChatGPT. (2023, November 7). Climate Change Resistance: How Local Adaptation Benefits Certain Bird Species. PerEXP Teamworks. [News Link]

Scientists at Cornell University, in collaboration with their peers, have conducted comprehensive whole genome sequencing of North American song sparrows. This genetic analysis has unveiled the genetic basis for the variation in body sizes observed within this species. This research represents the initial findings of a broader project aimed at sequencing the genomes of song sparrows across North America, encompassing nearly all of the 25 recognized subspecies.

This recent study, featured in Nature Communications, was conducted by a team of scientists hailing from various institutions, including the University of British Columbia, the Cornell Lab of Ornithology, Ouachita Baptist University, and the University of Alaska, Fairbanks.

The study provides backing for Bergmann’s Rule, a biological principle suggesting that, in general, within species capable of regulating their own body temperature, adaptation to colder environments favors larger body sizes, whereas warmer climates favor smaller body sizes. Larger bodies are better at conserving heat, while smaller bodies assist in staying cooler.

Song sparrows residing year-round on Alaska’s Aleutian Islands exhibit body sizes up to three times larger than their counterparts in the vicinity of San Francisco Bay.

Co-author and researcher Jennifer Walsh at the Cornell Lab of Ornithology emphasized the remarkable size disparity among song sparrows. She mentioned that the study’s findings demonstrate the song sparrows’ significant ability to adapt to local environmental changes and clarify the genetic mechanisms responsible for these adaptations. She expressed surprise that the genetic component leading to the substantial size difference was relatively straightforward, as they had initially expected a more complex genetic interplay or the involvement of multiple genes to account for the considerable size variations.

In this research, the scientists conducted genome sequencing and comparative analysis using 79 genomes representing nine song sparrow subspecies. This genomic investigation took place at the Fuller Evolutionary Biology Program, situated within the Cornell Lab of Ornithology.

The tissue samples employed in this research were sourced from specimens archived at the University of Alaska Museum of the North, collected during the years 1997 to 2000. Additionally, previously published whole genomes for California subspecies were integrated into the study. Song sparrows were chosen as a study species due to their widespread distribution and their ability to thrive in diverse environmental conditions, making them a valuable subject for research.

The lead author, Katherine Carbeck, a Ph.D. candidate at the University of British Columbia in Vancouver, explained the findings of the study. The research identified eight gene variations in the sequenced genomes, and these variations were associated with body mass, aligning with the expectations of Bergmann’s Rule. This indicates that there is a genetic foundation for the song sparrows’ ability to adapt to local climate conditions, spanning a wide range from the coldest northern locations to the warmest areas of their habitat in California.

The statement highlights the significance of microevolutionary processes, which involve changes happening over relatively short timeframes. These processes are essential for the survival of song sparrows, especially in the face of new and rapidly changing climate conditions, as emphasized by Carbeck.

The findings offer an optimistic outlook for the future of song sparrows, according to Peter Arcese, a co-author and professor in UBC’s department of forest and conservation sciences. Arcese suggests that the research implies that local song sparrow populations, which have adapted to their specific environments, have the potential to continue adapting to climate change. To support this ongoing adaptation, it’s crucial to ensure that habitat conditions are maintained, allowing for the movement of individuals and genes between different populations of song sparrows.

Having insights into the intricacies of microevolution is highly significant for conservation efforts, as pointed out by the scientists. This knowledge has practical implications, particularly in the context of song sparrow conservation. For instance, while song sparrow populations in northwestern areas like Alaska and British Columbia currently exhibit stability or population growth, the situation is quite different for populations along the West Coast of the continental United States. In these regions, some populations, such as those near San Francisco Bay, are even listed as threatened at the state level.

Decreases in specific parts of their range could result in the loss of genetic diversity in specialized local populations, even if the overall species trends are positive. While song sparrows have demonstrated significant adaptability to local climates, there are inherent limits to this adaptability. Carbeck emphasized that while micro-evolution might counteract some of the impacts of climate change, the crucial issue remains whether local adaptation can match the rate at which broader climate changes are occurring.


  1. NEWSPAPER Leonard, P. & Cornell University. (2023, November 7). Local adaptation may buffer some birds against climate change. []
  2. JOURNAL Carbeck, K., Arcese, P., Lovette, I., … (2023). Candidate genes under selection in song sparrows co-vary with climate and body mass in support of Bergmann’s Rule. Nature Communications, 14, 6974. [Nature Communications]

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