What makes little birds so loud?

What makes little birds so loud?
July 5, 2018

“If you are ever in the bizarre circumstance to be at the same altitude as these birds in the forest canopy, you would get a sense of how incredibly loud they are,” says UMass Amherst Professor of Biology Jeff Podos. Podos has received a Fulbright Scholar grant to study songbirds of the Amazonian rain forest who communicate vocally “in unusual ways”— in this case, even though they are small in size, the birds deliver songs that can be heard a mile away.

Podos, an expert in bioacoustics, will travel to Manaus, Brazil, at the confluence of the Amazon with the Rio Negro, where he is collaborating with Mario Cohn-Haft, curator of birds at the National Institute of Amazonian Research (INPA). Using sound-level meters, high-quality sound recorders, and high-speed video, the team intends to document how these species interact with their habitat through their song.

Make no mistake: these birds are rock-band loud. Bellbirds, neotropical perching birds in the Cotinga family, emit a clanging sound that rings out through the cloud forest. To make their loud cry, screaming pihas open their beaks almost to disarticulation. “They’re really cranking out the performance,” says Podos. “They’re putting their whole body into it.”

And body is the key. Behaviorally, the birds’ loud sound may be an adaptation to their environment, where they tend to be at some distance from one another. But how do their bodies allow for such a long-distance song transmission? Bellbirds, for example, boast a thickened abdominal wall with embedded ribs that boosts their acoustics.

The team will study the birds’ morphology: how their physical aspects influence the way they sing, and connect their body forms to the sounds produced: “We’re going to tap into extreme cases of birds doing hard-to-do things through their physiology.”

Understanding the importance of physiology in sound is a growing trend, explains Podos: there is increased appreciation in his field of the way sound emerges from an animal’s body structure, which has adapted in response to its environment—and how that body structure in turn sets parameters for the performance, in an ongoing evolutionary feedback loop.

In addition to supporting his field research, Podos’s Fulbright will also sponsor his teaching graduate-level courses in bioacoustics at INPA and at the Federal University of Amazonas.

The deepest purpose of the bird study is to add new layers to how we conceive of biodiversity. “It’s fun to identify new species and say who they are,” says Podos, “but it’s even more fun to ask, ‘What are they doing? And how do they do what they’re doing, and what is the effect of this thing they are doing?’”

The Fulbright Scholar program was established in 1946 by the U.S. Department of State’s Bureau of Educational and Cultural Affairs to emphasize science diplomacy and international research collaborations between American researchers and their colleagues around the world. UMass Amherst has been ranked as a top-producing institution for Fulbright Scholars in 2017–18 by the U.S. Department of State’s Bureau of Educational and Cultural Affairs.

Ream more:

The Podos Lab

Jeff Podos