News Life High altitudes may be a climate refuge for some birds, but not these hummingbirds Anna’s hummingbirds seem to struggle to hover when there’s less available oxygen Anna’s hummingbirds hovering at 3,800 meters above sea level should have been working harder to stay afloat in the thinner air. But their metabolic rate dropped. Jerome Gaw Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Rachel Crowell May 26, 2022 at 6:00 pm Cooler, higher locales may not be very welcoming to some hummingbirds trying to escape rising temperatures and other effects of climate change. Anna’s hummingbirds live no higher than about 2,600 meters above sea level.