Singing in the rainforest: Public vs. private signaling by a tropical rainforest bird

According to the Chinese proverb, a bird sings because it has a song, not because it has an answer. A team of French and Brazilian researchers, however, may have the answer as to how the song of Brazilian white-browed warbler has become so well-adapted to the acoustic properties of the rainforest environment. The study, led by Nicolas Mathevon and Thierry Aubin, is published in the online, open-access journal PLoS ONE on February 13.

Understanding the evolution of acoustic communication systems in animals is a hot topic in evolutionary biology and one of the main challenges is to understand how environmental pressures drive this evolution. Mathevon and his colleagues show that the song of the white-browed warbler, a species living in the Brazilian Atlantic rainforest is particularly well-tailored to the acoustic properties of the environment, with its dense vegetation and can vary in its acoustic properties depending on whether the message is “public” or “private.”

Territorial males signal their species identity using a song acoustic feature resistant to propagation, making this information available to remote individuals. Conversely, information concerning their individual identity is supported by song features susceptible to propagation, and thus restricted to neighbours.

Besides this public versus private signalling, males can locate the singers by using propagation-induced song modifications. The design of this communication thus appears well matched to the acoustic constraints of the rainforest and to the ecological requirements of the species.

These results emphasize that the efficiency of a sound communication system results from a coding/decoding process particularly well tuned to the acoustic properties of the environment. This allows the establishment of efficient local communication networks in the particular habitat of a tropical forest.

The tropical rainforest ecosystem provides a unique opportunity to experimentally test theoretical models of acoustic communication. This emphasizes the critical importance of tropical areas for addressing key biological questions and reinforces the urgency for protecting such major biodiversity hotspots as those of the Brazilian Atlantic forest.

Citation: Mathevon N, Aubin T, Vielliard J, da Silva M-L, Sebe F, et al (2008) Singing in the Rain Forest: How a Tropical Bird Song Transfers Information. PLoS ONE 3(2): e1580. doi:10.1371/journal.pone.0001580 (http://www.plosone.org/doi/pone.0001580)

Source: Public Library of Science

Related stories:

Tuning in to a new language on the fly: Effects of context and seasonality on songbird brain
Research conducted at Rutgers University has shown that exposure to a changed acoustic and social environment can rewire the way the brain processes sounds. Beginning in the cochlea of the inner ear, nerve cells of the auditory system parse incoming sounds into their different components. Study of the responses of individual brain cells has shown that they respond best to a particular frequency (pitch) of sound, less well to nearby frequencies, and poorly to distant sound frequencies. The range of effective frequencies can be measured as the "tuning width." Cells with similar tuning are found together, producing an orderly map of all the possible frequencies spread out across the auditory part of the brain.
Birdsong not just for the birds
Switch on the mike, start the recording, the stage is set for the local fauna! Computer scientists from the University of Bonn, in conjunction with the birdsong archives of Berlin's Humboldt University, have developed a kind of 'Big Brother' for birds.
How strong is a hurricane? Just listen
Knowing how powerful a hurricane is, before it hits land, can help to save lives or to avoid the enormous costs of an unnecessary evacuation. Some MIT researchers think there may be a better, cheaper way of getting that crucial information.
What gets a female's attention -- at least a songbird's
Male songbirds produce a subtly different tune when they are courting a female than when they are singing on their own. Now, new research offers a window into the effect this has on females, showing they have an ear for detail. The finding provides insights not only into the intricacies of songbird attraction and devotion but also into the way in which the brain develops and responds to social cues, in birds – and humans.
Music lovers get the 'meta' of digital audio
Groundbreaking audio software developed by European researchers could help music lovers jump to the hidden beats.
Researchers report breakthrough in rapid malaria detection
A research team led by Dr. Paul Wiseman of the Departments of Physics and Chemistry at McGill University has developed a radically new technique that uses lasers and non-linear optical effects to detect malaria infection in human blood, according to a study published in the Biophysical Journal. The researchers say the new technique holds the promise of simpler, faster and far less labour-intensive detection of the malaria parasite in blood samples.
Probing Question: How do songbirds learn to sing?
"Poor Sam Peabody, Peabody, Peabody!"
"Please, please, pleased to meetcha!"
"Who cooks for you?"
Studies Shed New Light on Blue Whales and Their Calls
Using a variety of new approaches, scientists at Scripps Institution of Oceanography at UC San Diego are forging a new understanding of the largest mammals on Earth.

News discussion:

General Science news