Anyone who enjoys birdwatching knows that birds have different calls and songs to suit different situations, and species have their own languages, just like humans says Sheena Harvey.
A new study by a team from the University of Manchester has established that, in one particular respect, birds’ use of language also follows a very similar pattern to ours – the way that short words are favoured over long for speed and efficiency.
“Since ancient times, people have been fascinated by birdsong and imagined it to be the ‘language of birds’, states the team, led by mathematical biologist, Dr Tucker Gilman. “This analogy has become more exciting as researchers have discovered that many genes and parts of the brain involved in birdsong learning and development are also involved in human speech.”
In the current study the scientists, in collaboration with colleagues at Chester Zoo, set out to establish if birds followed the same principle as humans of ‘least effort brings greatest efficiency’. At the core of this principle is what language specialists call Brevity Law, or Zipf’s Law of Abbreviation. In the 1940s, linguist George Kingsley Zipf wrote that the more frequently a word is used, the shorter the word tends to be. His examples – the, and, to, be, a, of, in – were the most common words in the English language and very short.
Zipf’s Law has since been shown to apply to frequently used words in many other languages. Not only that, but where an original word is long, but commonly used, there is a tendency to create a shorter version. For example, ad for advertisement, lab for laboratory, ID for identification, vet for veterinarian.
Do birds approach communication in the same efficient way, wondered the Manchester researchers. Getting an answer was not straightforward, as any birdwatcher will know. Co-author Dr Rebecca Lewis, Conservation Scientist at Chester Zoo, says: “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.”
So studying Zipf’s Law in birdsong is far more complex than in human language, which is why the team employed a computational tool called ZLAvian. It was able to compare patterns and combine data across more than 600 bird’s songs from seven different species in 11 bird populations. Eventually, the scientists were able to conclude that the most frequently used birdsong phrases they recorded were indeed shorter.
The research offers new insight into how animals communicate and how developing short, efficient language may be universal. Dr Lewis says: “We hope ZLAvian will make it easier for other researchers to explore these patterns in more birds but also other animals in the future.”