Hummingbirds are at risk of extinction due to global warming


Hummingbirds could be at risk of extinction due to global warming, Newsweek reports on a new study. Scientists predict that bird species will have to migrate north in search of cooler climates or possibly perish completely.

Since hummingbirds have the most difficult type of flight in the entire animal kingdom, hovering requires significantly more energy and oxygen than steady flight, as Study Finds reports.

Bird species, however, are not affected by air scarcity. From Alaska to South America, they thrive in high mountains.

Study Anna’s Hummingbird Species

According to the study, the obstacles associated with shifting gears may be too great for small, nimble aeronauts.

Austin Spence, the study’s stated lead author and Ph.D. student at the University of Connecticut, explains that overall, the data presented implies that low atmospheric pressure and low oxygen availability may impair the hovering performance of hummingbirds when subjected to the acute challenge of the high altitude.

In the study, Spence explains that when there is less oxygen available, thinner, colder air is especially difficult for species trying to stay warm.

The study focused on Anna’s hummingbird species (Calypte anna), which can live up to 2,800 meters above sea level.

They lured the bird species into net traps from locations around California, including Sacramento, 10 meters above sea level, and Mammoth Lakes, 2,400 meters.

The researchers then moved them to a 1,215-meter aviary in western California.

After a few days in their new habitat, the birds were given a small funnel they could put their heads in while hovering and sipping delicious syrup.

The metabolic rate of the small organisms was recorded overnight as they let their metabolism drop while they slept.

During sleep, this type of mini-hibernation conserves energy. Hummingbirds can cool their bodies to less than 4°C at night, the lowest temperature ever recorded in a bird.

They have wings that beat at a rate of over 10 times per second and they use their hovering abilities to drink nectar from thousands of flowers during the day.

Hummingbirds have a small heart that rises about 1,000 times per minute, but only 50 times when at rest. The birds were transported by Spence and his colleagues to a nearby research site at 3,800 meters above sea level near the summit of Mount Barcroft, where the air is thinner, with about 39% less oxygen and a temperature about 5°C.

The hovering hummingbirds should have worked harder to stay aloft 1,000 meters above their natural range, but they experienced a 37% drop in metabolic rate.

When the researchers looked at the energy expended at the top of the mountain by the birds that started out around sea level and those at the upper end of their range, they found that they were all working the same way. way.

Also read: For at least 50 years, the bird population has been falling steadily in the tropical rainforest

Additionally, the hummingbirds began to lower their metabolic rate for longer periods during the night. They were in torpor for more than 87.5% of the freezing night at high altitude.

Spence explained that birds use torpor when it’s extremely cold.

The researchers also looked at the size of the animals’ lungs to see if they got bigger in those that came from higher altitudes to compensate for the lack of oxygen.

The team’s findings show that while the birds’ lungs weren’t bigger, their hearts were.

The findings in the Journal of Experimental Biology have implications for the future of hummingbirds, as avian species seek more comfortable conditions due to climate change.

The results presented by Spence and his team show that reduced oxygen availability and low atmospheric pressure can be difficult challenges for hummingbirds to overcome.

Related article: Bizarre “change in behavior” observed in birds linked to climate change

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