Scientists Suspect Simplicity of Bird Songs

Researchers in America have created a simple device that can recreate the complex patterns of bird songs. The small rubber device acts like a bird's vocal tract, and it can be used simply by blowing through the tube. The team's findings suggest that the standing idea that birds developed neurological controls over their vocal tracts in order to produce distinctive calls is incorrect.

The scientists aim to share the findings with biologists in order to find out if the data can glean any insight into how birds are able to produce complex song behavior. The team members were not confident that they would be able to produce a song with the same complexity as those sung by wild song birds.

They were merely experimenting, and the results were complex and beautiful bird songs that impressed the researchers. The device itself is very simple, consisting of two pieces of rubber that are attached, with some slack left in the middle to imitate a vocal tract.

The device is held taut by a motor that simulates the action of muscle contraction on a bird's vocal cords. An air source is introduced to replicate the breathing involved in the process. The vocal tract is nothing more than an elastic membrane in the throat. When probed and caused to tense by muscular contractions, it is set into vibration.

The aim of the research project was to discover how to control the vibrational frequencies. The scientists replicated a number of bird songs, producing clear imitations of common songbirds. Even the song of the zebra finch, a notoriously complicated tune, was replicated well in the project. While they were unable to completely mimic the song, the team produced very impressive results.

The zebra finch is an ongoing project on which the team expects to continue working. Members suggest that the process just needs some tweaking before the process will be achieved. The elusive song may not be out of the researchers' reach for long. The research that resulted in the discovery was geared towards expanding knowledge about the physiological basis of vocalization.

The simplistic design of the vocalization replication device surprised scientists because of their ability to replicate such complex birdsongs from a wide range of bird species. The team worked in tandem with neuroscientists studying the ways in which birds may develop their ability to sing.

It had been considered to be a complicated physical process, and the team aimed to gain a better understanding through the application of physics.

Because the patterns of bird songs are unusually complex behaviour, they have been well studied by many scientists. Neuroscience has a long history of studying the manner in which offspring learn to sing from their parents. They have suggested that the process requires a series of changes in the brain that allow the young to gain mastery over their vocalizations.

The results of these findings suggest that it is possible to produce complex vocalizations without sophisticated neurological inputs required. A single muscle can produce a vast number of sounds through the ways that it interacts with the membrane.

The neurological control necessary to produce the actions does not have to be as complex as scientists had previously expected it to be. The research team was quick to note that such speculations are best left to specialists in that particular field.

They do not want to make claims with which biophysicists or neurologists will take issue. The results they intend to publish pertain to their own data, but they are keen to pass it on to specialists in other fields.

One team member is working on a mathematical model to determine if there are underlying principles that lead to complex bird songs. The findings are set to be published within the coming months.

Source : BBC Photo by : Karen Hull