Less available food, such as fruit or insects, in dryer weather might lead to smaller body size. In general, smaller animals have a larger ratio of surface area to body size, so they dissipate more heat faster than a bigger animal. The researchers themselves are unsure what advantage the wing length changes give the birds, but smaller birds may have an easier time keeping cool. So why would birds be evolving smaller bodies and longer wings? The birds in the study spend their whole lives in the undisturbed rainforest understory, just below the tree canopy, so habitat degradation doesn’t factor in, either. Researchers focused on bird species that don’t migrate, which ruled out factors such as exposure to different habitats as the cause of any physical changes.
#Birds that have there wings clipt series#
“This is a valuable and fascinating paper based on 40 years of data, pretty much unheard of in the tropics,” says Cagan Sekercioglu, a National Geographic Explorer, photographer, and ornithologist at the University of Utah School of Biological Sciences, in Salt Lake City, via email.īecause of the study’s “long time series and large sample sizes, the authors were able to show the morphological effects of climate change on resident tropical birds,” said Sekercioglu, who wasn’t involved in the study. These climatic changes overlapped with changes in the birds’ builds, the researchers say, with the dryer climate going further to explain the changes. Precipitation increased by 13 percent during the rainy season but decreased by 15 percent in the dry season, making for a hotter, dryer climate overall. Temperatures increased by one degree Celsius during the wet season and 1.65° Celsius in the dry season.
Meanwhile, all the species showed some decrease in average body mass, while a third grew longer wings.ĭuring the study period, the average temperature in the region rose, while precipitation declined. They report on November 12 in the journal Science Advances that 36 species have lost substantial weight, as much as 2 percent of their body weight per decade since 1980. )įor the new study, researchers collected the biggest dataset so far on the Amazon’s resident birds, representing 77 non-migratory species and spanning the 40 years from 1979 to 2019. For instance, a 2019 report by the National Audubon Society found that more than two-thirds of North America’s bird species will be vulnerable to extinction by 2100 if warming trends continue on their current course.
Unauthorized use is prohibited.īirds are often considered sentinel species-meaning that they indicate the overall health of an ecosystem-so scientists are particularly interested in how they’re responding to climate change.
0 kommentar(er)
