“Hummingbirds need to eat constantly because they use up energy very quickly. If we had their metabolic rate, we’d need to eat 300 hamburgers a day to survive!” explained Anusha Shankar, a postdoctoral fellow conducting research at the Cornell Lab of Ornithology, in an interview with Birds & Blooms. Consuming up to three times their body weight in primarily nectar and insects, hummingbirds have a unique and symbiotic relationship with their co-evolutionary plant species within the food web: the buzzing birds rely on specific flowers as their food source, while those flowers are in turn pollinated and can complete their reproductive life cycle. It is not a surprise that climate change, on top of human interference with hummingbird habitats, has unfortunate implications on the feeding patterns of these birds. The phenology, or seasonal timing, of hummingbird migration versus blooming times provides a key perspective on the impacts of climate change from the bird’s eye view.

Migrating north from Central America to western United States every spring, the return of Broad-tailed hummingbirds is becoming more and more out of sync with the blooming of glacier lilies whose nectar their diet comprises. In 2012, the U.S. National Science Foundation reported that the time interval between the first bloom and the first hummingbird arrival decreased by around two weeks compared to the 1970s, this shift being attributed to the Earth’s rising temperatures. Moreover, this shift would increase, as certain years had already experienced occurrences of hummingbirds arriving past glacier lily blooming times. Nature Conservancy Canada similarly notes that the population of Rufous hummingbirds is estimated to have declined by over 60 per cent since 1966, in part to due loss of habitats, but also due to changes of blooming times in breeding grounds spanning across Yukon, British Columbia and western Alberta.

Can hummingbirds relocate to higher elevations to escape the effects of climate change? A team of scientists conducted a study to answer this question and published their results in the Journal of Experimental Biology. A group of Anna’s hummingbirds, a species that has already begun to move towards higher elevations, was placed in a location 1200m above their current elevational limit. Especially without long-term acclimatization, the decrease in oxygen and pressure resulted in the birds exhibiting lower hovering metabolic rates (or energy efficiency) while flying and an increased use of torpor, a state where all hummingbird body functions are decreased to conserve energy in colder thermal conditions. This makes it unlikely for these birds to relocate significantly above their current altitude limit, which further emphasizes the importance of alleviating the root causes of climate change.

In addition to reducing the human footprint on rising temperatures and defending hummingbird habitats, hummingbird protection can be supported through citizen science. Initiatives such as Birds Canada, Hummingbirds at Home, and eBirds make it easy for the public to contribute data on bird distribution and behavior to better inform the conservation management of hummingbirds, a significant species for plant pollination in ecosystems, but also a culturally significant species: hummingbirds represent joy, strength, luck, intelligence, beauty, devotion, and love among Pacific Coast Indigenous cultures.

Works Cited

“How Climate Change Affects Hummingbirds’ Feeding Behavior.” Audubon, 9 Jan. 2015, www.audubon.org/httpswwwaudubonorgmenuconservation/how-climate-change-affects-hummingbirds-feeding-behavior.

“Hummingbird Evolution.” Arizona State University, 20 May 2014, askabiologist.asu.edu/hummingbird-evolution.
“Hummingbirds.” Pollinator.org, www.pollinator.org/learning-center/hummingbirds.

“Hummingbirds, Lilies Thrown off by Climate Change | American Association for the Advancement of Science (AAAS).” American Association for the Advancement of Science (AAAS), 2024, www.aaas.org/taxonomy/term/9/hummingbirds-lilies-thrown-climate-change.

Kaufman, Kenn , and Kimberly Kaufman. “What Foods, How Often and How Much Do Hummingbirds Eat?” Birds and Blooms, 10 Feb. 2022, www.birdsandblooms.com/birding/bird-species/hummingbirds-swifts-and-swallows/what-do-hummingbirds-eat/.

Magazine, Smithsonian, and Elizabeth Gamillo. “Scientists Moved Hummingbirds to High Elevations to See How Climate Change Might Affect Them.” Smithsonian Magazine, www.smithsonianmag.com/smart-news/hummingbirds-may-help-scientists-understand-how-animals-could-adapt-to-climate-change-180980163/.

McKinney, Amy M., et al. “Asynchronous Changes in Phenology of Migrating Broad-Tailed Hummingbirds and Their Early-Season Nectar Resources.” Ecology, vol. 93, no. 9, Sept. 2012, pp. 1987–1993, https://doi.org/10.1890/12-0255.1.

“Rufous Hummingbird.” Www.natureconservancy.ca, www.natureconservancy.ca/en/what-we-do/resource-centre/featured-species/birds/rufous-hummingbird.html.
Spence, Austin R., et al. “Anna’s Hummingbird (Calypte Anna) Physiological Response to Novel Thermal and Hypoxic Conditions at High Elevations.” Journal of Experimental Biology, vol. 225, no. 10, 15 May 2022, journals.biologists.com/jeb/article/225/10/jeb243294/275376/Anna-s-hummingbird-Calypte-anna-physiological, https://doi.org/10.1242/jeb.243294. Accessed 16 Nov. 2022.

“The Hummingbird Symbol - Native Art Symbols and Meanings.” Cedar Hill Long House Native Art Prints, 18 Mar. 2020, cedarhilllonghouse.ca/the-hummingbird-symbol-native-art-symbols-and-meanings/.

“Where Have All the Hummingbirds Gone?” Nsf.gov, 2023, www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=124345&preview=false. Accessed 30 Sept. 2024.

Image credits:

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By Charles J. Sharp - Own work, from Sharp Photography, sharpphotography, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47658668