Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chickadees’ alarm calls carry information about size, threat of predators

24.06.2005


Black-capped chickadee


There’s more than meets the human ear when the black-capped chickadee lets its flock mates know a predator is lurking about by giving out its familiar "chick-a-dee-dee-dee" call.

The small songbirds, which are common throughout much of North America, use that signature call in a wide variety of social interactions including warning of predators. And it turns out that those alarms are far more subtle and information-packed than scientists previously imagined.

Writing in the current issue of the journal Science, researchers report that chickadees use one of the most sophisticated signaling systems discovered among animals. The calls warn other chickadees not only if a predator is moving rapidly, but also transmit information on the degree of threat posed by stationary predators of different sizes.



Chris Templeton, a biology doctoral student at the University of Washington and lead author of the study, said chickadees produce two very different alarm signals in response to predators. When they see flying raptors – birds of prey such as hawks, owls and falcons – they produce a soft, high-pitched "seet" call. But when they see a stationary or perched predator, the birds use a loud, wide spectrum chick-a-dee-dee-dee alarm to recruit other chickadees, as well as other bird species, to harass or mob the predator. Spectrographic analysis of more than 5,000 recorded chickadee mobbing alarm calls made under semi-natural conditions showed that the acoustic features of the calls varied with the size of the predator. And when the recordings were played back to the birds through speakers, their mobbing behavior was related to the size and threat presented by the potential predator.

Templeton said chickadees can alter their mobbing calls in a number of ways, most of which humans can not hear. Most typically they change the dee dee dee not at the end of the call, sometimes adding five, 10 or 15 dees.

"You would certainly might notice a change in the number of dee notes in their call if a neighbor’s cats was around harassing them. With something really dangerous, such as a pygmy-owl perched near some chickadees in our aviary, we heard as many as 23 added dees," he said.

The research was triggered when Templeton noticed the chickadees responding differently to a variety of predators inside an aviary. So the researchers set up an outdoor experiment in a semi-natural aviary with 15 different live perched or leashed predators.

Thirteen of these were raptors. Two were mammals, a domestic cat and a ferret, which resembles weasels that prey on small birds.

The birds of prey ranged in size from large owls, such as the great gray owl and great horned owl that usually feed on small mammals, to the small pygmy-owl and the American kestrel that hunt small mammals and birds. The smaller raptors represent a greater threat to the agile chickadees than the larger ones because they are more maneuverable in flight and can readily catch small birds.

"That’s why a pygmy-owl is more dangerous to a chickadee than a great horned owl that has a large hooked beak and big talons. A great horned owl going after a chickadee would be like a Hummer trying to outmaneuver and catch a Porsche, "Templeton said.

The chickadees also were exposed to a perched bobwhite quail, a non-predatory species, as a control animal, and did not react to it.

He noted that the chickadees are assessing risk on the basis of body size, but since they don’t react to the bobwhite quail, they also seem to be assessing individual species.

In the future, Templeton would like to examine the chickadee’s "seet" calls to see if they change in response to different raptors flying above them. If they do, this would be even more impressive since the birds would have such a brief glimpse as a predator flew by.

Joel Schwarz | EurekAlert!
Further information:
http://www.washington.edu

More articles from Life Sciences:

nachricht First use of vasoprotective antibody in cardiogenic shock
17.05.2019 | Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.

nachricht A nerve cell serves as a “single” for studies
15.05.2019 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

Im Focus: A step towards probabilistic computing

Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future

When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...

Im Focus: Recording embryonic development

Scientists develop a molecular recording tool that enables in vivo lineage tracing of embryonic cells

The beginning of new life starts with a fascinating process: A single cell gives rise to progenitor cells that eventually differentiate into the three germ...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Discovering unusual structures from exception using big data and machine learning techniques

17.05.2019 | Materials Sciences

ALMA discovers aluminum around young star

17.05.2019 | Physics and Astronomy

A new iron-based superconductor stabilized by inter-block charger transfer

17.05.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>