The latest heat waves are concerning for birds, whose eggs could be damaged from the skyrocketing temperatures. When extremely higher-than-normal temperatures occur in a region and prevail for several days, there is a possibility that bird eggs may not be able to incubate. Scientists are warning that such instances may drive vulnerable bird species out of existence.
According to a study, a heat wave during the peak of Australia’s summer in February 2017 saw almost all zebra finch eggs fail to incubate. The maximum air temperature stayed above 40°C (104°F) for eight days straight. Ideally, zebra finches incubate their eggs at about 36°C to 38°C.
“The temperatures that killed these embryos, they are obviously just too much for the embryos to take,” Simon Griffith, professor and researcher at Macquarie University in Australia, told EcoWatch reporter Richa Malhotra.
Griffith, who was part of a larger study group, said that his team visited hundreds of nests to monitor the status of the eggs before, during and after the heatwave. They tested the eggs to feel the heartbeat of the embryos.
“Before the heatwave, we could still see the heartbeat and then after these two or three days of heat when we checked the eggs, the heartbeat had stopped,” Griffith said.
Tragically, only 23 out of 25 egg clutches managed to hatch. This resulted in just two egg hatchings out of 100. Even more alarming is the fact that the hatched chicks also died a few days later.
According to Griffith, zebra finches are well-adapted birds that can survive in extremely harsh climates. Further, they can lay eggs frequently and at any time of the year. But he warns that the same scenario could be replicated for other bird species, particularly as temperatures continue to climb.
Andrew McKechnie of the South African National Biodiversity Institute said, “Widespread heat-related mortality of eggs, similar to that documented here, should be of particular concern for threatened species.”
In 2020, McKechnie documented the deaths of more than 100 birds and bats in South Africa following a single day of extreme heat. The majority of the birds that died were songbirds, despite their tolerance to high temperatures.
Griffith explained things are likely to get worse as the globe becomes hotter. However, he also believes that birds may adapt and be able to tolerate higher temperatures where water is available. The problem is that the high temperatures are threatening existing water sources.
“Where there will be problems is where there is no water,” Griffith said.
Image via William Warby