Songbirds like cardinals and sparrows adhere to a consistent schedule each year. During spring, they construct nests and nurture their young from nestlings to fledglings. However, as springtime temperatures escalate due to climate change, scientists have observed struggles among bird populations in preserving the lives of their offspring.
A study published on Thursday in the journal Science analyzed over 150,000 nesting attempts from 1998 to 2020. The study found that unusually warm temperatures during nesting seasons significantly hindered the reproductive success of more than 50 species of birds, especially songbirds.
For birds nesting in agricultural areas with minimal tree cover or shade, the likelihood of successfully raising at least one nestling declined by 46% during periods of abnormally high temperatures.
The research paper echoes the growing concerns of ecologists and ornithologists about the substantial decline in bird populations worldwide. Since the 1970s, North America’s bird population has dropped by nearly 3 billion. Sparrows, swallows, warblers, and finches, among others, continue to vanish.
This alarming trend is likely influenced by various factors, such as pesticide pollution, habitat loss, and climate change. The extreme heat associated with climate change prevents nestlings from maturing, as stated by Katherine Lauck, a researcher at the University of California, Davis and the lead author of the study.
Young birds in the nest are unable to regulate their body temperature, rendering them more vulnerable to extreme temperatures. Additionally, they are entirely dependent on their parents to provide them with food, which becomes more challenging in hot conditions.
“The reproductive cycle of birds makes them especially susceptible to the impacts of climate change,” remarked Lauck.
Scientists have already observed that rising temperatures have caused certain bird species to nest earlier during cooler months. Furthermore, some birds have been getting smaller as a result of climate change. In extreme cases, such as Australia’s recent heatwaves, both adult and baby birds have perished.
The study emphasizes that the most vulnerable birds reside in unshaded agricultural areas, while those living in forests with ample tree cover and shade were largely unaffected by warmer-than-average temperatures. In fact, high temperatures slightly increased the likelihood of nestling success for forest-dwelling birds.
The disparity in reproductive success between forest and agricultural bird populations highlights how land use can exacerbate high temperatures for wild birds, according to Conor Taff, an ecologist and researcher for the Cornell Lab of Ornithology who was not involved in the study.
Taff suggests that protecting bird populations from heat can be as simple as introducing forest patches in agricultural areas to provide birds with refuge from elevated temperatures. However, the primary focus should be on reducing greenhouse gas emissions to mitigate global warming.
Preserving bird populations is crucial for maintaining healthy ecosystems, according to many ecologists. David Wiedenfeld, the senior conservation scientist at the American Bird Conservancy, who was not part of the study, asserts that birds perform vital services as pollinators, pest controllers, and fertilizers. Additionally, they are a source of aesthetic pleasure for many.
Wiedenfeld finds the decline of bird populations extremely concerning, stating, “Birds are literally the canary in the coal mine. They serve as reliable indicators of environmental changes.”
This article was originally published on NBCNews.com.
