McConnell’s flycatcher
The McConnell’s flycatcher is found in several countries in South America. The petite bird lives throughout the understory of the Amazon but is not often seen (its green-and-yellow plumage makes a great camouflage). Like many of the other birds the team studied, flycatcher populations remain robust, a reminder that climate change doesn’t always mean immediate harm to a population’s numbers—sometimes, it can mean changes to animal morphology.
“These birds don’t vary that much in size. They are fairly fine-tuned, so when everyone in the population is a couple of grams smaller, it’s significant,” said co-author Philip Stouffer, a conservation biologist at LSU, in a university press release.
Because species’ wingspans tended to increase as their mass decreased, the researchers suspect the changes may help reduce the wing load, making them more efficient in flight. But they don’t know for sure. “Are the changes we’re witnessing related to flight? Are the changes evolution (genetic changes), as opposed to plasticity (changes in phenotype without DNA alterations)? Is it really related to heat exchange? There’s much more work to be done,” said Jirinek.
