(Author: Physorg; Photo: Wikipedia; 20 March 2017)
Innovative research looking at the timing and sequence of bird calls could provide new insight into the social interaction that goes on between birds. It will also help teach machines to differentiate between man-made and natural sounds and to understand the world around them.
The work is being led by Dr Dan Stowell, a research fellow in machine listening at Queen Mary University of London (QMUL). It is supported through an Early Career Fellowship from the Engineering and Physical Sciences Research Council (EPSRC). An audio slide-show Deciphering the dawn chorus on this research is available on YouTube with examples of the bird recordings.
In August 2015, Dr Stowell’s technology was released to the public in a smartphone app called Warblr. Users record the sound of a bird on their mobile device and the app analyses the sound, matches it with patterns of bird calls in its dataset and provides a list of possible species that the recording matches.
Dr Stowell is now building on this work to take the computer analysis of the sounds that birds make to a new level, to discover more about what messages are being communicated and who is dominating the conversations that are going on.
“Traditionally you would take explicit measures of things like how long is this sound, what frequency is that sound?” says Dr Stowell. “To go beyond this we use modern machine-learning methods where you don’t necessarily know how a computer has made a decision about a particular sound, but by training it, which means showing it lots of previous examples, we can encourage a computer algorithm to generalise from those.”
At the University’s laboratory aviary, female zebra finches provide Dr Stowell with plenty of audio examples for his work.
“We have put the timing of the calls together with acoustic analysis of the content of the call, for instance whether it is a short or long call. We examine factors such as does the probability of one bird calling increase or decrease after another bird calls or is there a more subtle interaction going on? Working out how strongly each bird influences another helps us to build a picture of the communication network that is going on in that group of birds.”