These birds communicate through feather flutters - and even have different accents

Some birds tweet, some chirp, but the fork-tailed flycatcher uses its feathers to communicate. And new research shows that the birds have different accents depending on their migratory patterns.

These tiny birds are known for their extra long tail feathers and aggressive personalities. Earlier research showed that the species was splitting into two sub-species, one that migrates, and one that doesn't. Evolutionary biologist Valentina Gómez-Bahamón wanted to know what is driving these species apart. 

First, she needed to identify the source of the birds unique fluttering noise, which they produce when they are mating, and also when responding to a threat. The team placed a taxidermied hawk in the flycatchers' territory in Colombia and filmed their resulting aggressive displays using slow motion cameras.

"I could actually see what was the the physical mechanism by which the feathers were producing the sound," said Gómez-Bahamón. "It's coming from the actual downstroke of the of the wings." 

These recordings not only confirmed the mechanisms that make these unique sounds, but also allowed them to confirm that the sounds differ depending on whether the birds migrate or not.

"The frequency of the sound is much higher in the migratory ones and also the structure is also different. It's much more conspicuous in the non migratory birds. You hear it clearly and it has a louder signal," said Gómez-Bahamón.

The migratory and non-migratory birds don't interbreed, and Gómez-Bahamón believes it's because communication is key to picking a mate, and if the two subspecies make different sounds, that could be what is making the difference.

Listen to Gómez-Bahamón's interview with Bob McDonald at the link above.

Written and produced by Amanda Buckiewicz.