Avian Efficiency 

All human languages have one thing in common: The more frequently a sound is used, the shorter it tends to be.  

This concept, called Zipf’s Law of Abbreviation (ZLA), is one based on the “principle of least effort.” 

Birds employ it, too, researchers now say. 

“In human language, if we say something a lot, we tend to shorten it – like saying ‘TV’ instead of ‘television’,” said Tucker Gilman, author of a new study, in a statement. “It turns out that the same pattern exists in birdsong.” 

While previous research suggested that animal communication might follow ZLA, scientists struggled to find clear evidence of it in birdsong because most birds only produce a few dozen distinct sounds compared with the thousands of words used by humans.  

“Studying ZLA in birdsong is far more complex than in human language,” study author Rebecca Lewis said in the statement. “Birds often have very few note types, individuals even within the same species can vary widely in their repertoires, and classifying notes is tricky, too.” 

As a result, researchers studied birdsongs by focusing on how often a single bird uses certain note types and how long those notes lasted. This allowed the team to study communication from an individual point of view rather than that of a population.  

They applied this system using an open-source tool called ZLAvian, which identifies the presence of ZLA by checking whether real-world patterns match or differ from simulated patterns.  

Through ZLAvian, researchers were able to analyze more than 600 songs from 11 bird populations across seven different species. 

The results showed that while individual populations didn’t always show clear signs of ZLA, a clearer pattern appeared when data were assembled: More frequently used bird song phrases were shorter on average. 

“We know that birds and humans share similarities in the genes and brain structures involved in learning to communicate, but this is the first time we’ve been able to detect a consistent pattern of ZLA across multiple bird species,” Gilman said. “There’s still a lot more work to be done, but this is an exciting development.”