The climate crisis is affecting bird body shapes, according to new research.
Climate change is disrupting bird evolution and our understanding of how birds process complex data, according to a report published this week in the journal Current Biology.
“…our data show that it has already affected the body shape and dimensions of modern house sparrows,” Nicole Koller, an assistant professor of biology at Ohio State University, told DeSmogBlog.
The research is based on a study conducted in the summer of 2015 and fall of 2016, in the central Australian Mardie National Park and the park’s Lake Wakool. The study looked at how climate change affected the sparrow’s body in carbon dioxide (CO2) concentrations of more than 350 parts per million (ppm) and correlated those changes with other factors, including levels of the other “greenhouse gas” carbon monoxide, or CMD.
Each of the four breeding pairs of sparrows had two females and one male. The sparrows had six-month periods when they were in a normally restful “summer daze” situation during which the males laid their eggs, and then another season (fall breeding season) during which they flew back and forth over the lake, forming bands of activity, some of them flying more than 250 feet long in a straight line.
At the time of the study, the Sparrows and the newly-produced eggs were outside of the survival window where energy used for reproduction is greatly reduced and the birds are most vulnerable to predators.
The study found a dramatic drop in food, water and ability to fly after a warm spell in which average high-range CO2 concentrations exceeded 100ppm (more than a five-fold increase in concentration), decreasing reproductive performance by up to a factor of two or three. This resulted in statistically significant drops in the body size, weight and length of the sparrows.
“Overall, the study raises substantial concerns about the wellbeing of large, bird-sized mammals,” Koller said. “We assume that a mammal can adapt to changes in their environment relatively quickly. However, there is strong evidence that the ecology of large vertebrates is very, very sensitive to changes in CO2 concentration. As CO2 concentration rises, the life span of some vertebrates decreases and they become, or turn into, less-sculpted creatures.”
In this case, this would be a situation in which the bird version of its model had evolved to an early-than-expected evolutionary stage where it could no longer readily adapt to the lifestyle of either mice or domestic-size mammals. These smaller mammals often have been caught in the headlights of climate change as well, becoming pack animals with poor reproductive performance.
The sparrows’ birds were no different, suggesting this important animal could become trapped in an evolutionary no-man’s land between habitat and type.
“Until now, we have been able to explain a lot of these changes in giant animals based on how they are becoming hungrier or more aggressive, or some other environmental reason. But now we’re learning that climate change is also having this effect on the body shape and hormone levels of birds,” said Koller.
“We’re talking about major population fluctuations. We were able to use this data to show we see a couple trends that are pretty strong. They all seem to be linked to increasing CO2 concentrations and the associated changes in life spans. If you put that all together with past research, you can get a pretty clear picture of how this could have a direct impact on future species dynamics.”