Navigation Links
Ecologists sound out new solution for monitoring cryptic species
Date:11/26/2009

Ecologists have at last worked out a way of using recordings of birdsong to accurately measure the size of bird populations. This is the first time sound recordings from a microphone array have been translated into accurate estimates of bird species' populations. Because the new technique, reported in the British Ecological Society's Journal of Applied Ecology, will also work with whale song, it could lead to a major advance in our ability to monitor whale and dolphin numbers.

Developed by Deanna Dawson of the US Geological Survey and Murray Efford of the University of Otago, New Zealand, the technique is an innovative combination of sound recording with spatially explicit capture-recapture (SECR), a new version of one of ecologists' oldest tools for monitoring animal populations.

Birds communicate by singing or calling, and biologists have long counted these cues to get an index of bird abundance. But it is much harder to work out the actual density of a bird population because existing methods need observers to measure either the distance to each bird, or whether they are within a set distance from the observer. This is straightforward if birds are seen, but difficult when birds are heard but not seen.

According to Dawson: "We devised a way to estimate population density of birds or other animals that vocalise by combining sound information from several microphones. A sound spreading through a forest or other habitat leaves a 'footprint'. The size of the footprint depends on how quickly the sound attenuates. Mathematically, there is a unique combination of population density and attenuation rate that best matches the number and 'size' of the recorded sounds. We used computer methods to find the best match, and thereby estimate density."

Dawson and Efford developed the method by recording the ovenbird a warbler more often heard than seen in deciduous forest at the Patuxent Research Refuge near Laurel, Maryland, USA. They rigged up four microphones close to the ground in a square with 21 metre-long sides. Over five days, they moved the microphones to 75 different points across their study area and recorded ovenbirds singing.

They chose the ovenbird as the species from which to develop the method because of its concise, distinctive song and because the males sing from the lower layers of the forest.

The new acoustic technique gives a more accurate estimate of bird numbers than using nets to capture birds, which can be stressful for the birds as well as time consuming for the researchers.

As well as helping assess populations of cryptic bird species such as the ovenbird, the new technique might be applied to measuring hard-to-reach populations of marine mammals, such as whales and dolphins. Developing ways of estimating whale and dolphin numbers acoustically is seen as critical for understanding these species' populations.

Recording the sounds has other benefits, too. "Sound intensity and other characteristics can be measured from the spectrogram the graph of the sounds to improve density estimates. Archiving the sounds also makes it possible to re-examine them, or to extract additional information as analytical methods evolve," says Dawson.


'/>"/>

Contact: Becky Allen
beckyallen@ntlworld.com
44-794-980-4317
Wiley-Blackwell
Source:Eurekalert

Related biology news :

1. The value of variation: Ecologists consider the causes and consequences
2. Ecologists question effects of climate change on infectious diseases
3. Ecologists report quantifiable measures of natures services to humans
4. Ecologists use oceanographic data to predict future climate change
5. Ecologists say metabolism accounts for why natural selection favors only some species
6. Studies of small water fleas help ecologists understand population dynamics
7. Biofuels and biodiversity dont mix, ecologists warn
8. Ecologists tease out private lives of plants and their pollinators
9. Ecologists, material scientists pursue genetics of diatoms elegant, etched casing
10. Ecologists discover city is uber-forest for big owls
11. National Science Foundation Fellow uses ultrasound to research bog turtles
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/19/2017)... New York , April 19, 2017 ... competitive, as its vendor landscape is marked by the ... the market is however held by five major players ... Safran. Together these companies accounted for nearly 61% of ... of the leading companies in the global military biometrics ...
(Date:4/11/2017)... Fla. , April 11, 2017 ... and secure authentication solutions, today announced that it ... Intelligence Advanced Research Projects Activity (IARPA) to develop ... Thor program. "Innovation has been a ... IARPA,s Thor program will allow us to innovate ...
(Date:4/5/2017)... 5, 2017  The Allen Institute for Cell Science ... a one-of-a-kind portal and dynamic digital window into the ... the first application of deep learning to create predictive ... lines and a growing suite of powerful tools. The ... and future publicly available resources created and shared by ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... ... Andi Purple announced Dr. Suneel I. Sheikh, the co-founder, CEO and chief research ... Inc. has been selected for membership in ARCS Alumni Hall of Fame ...
(Date:10/11/2017)... ... October 11, 2017 , ... Proscia Inc ... hosting a Webinar titled, “Pathology is going digital. Is your lab ready?” with ... adoption best practices and how Proscia improves lab economics and realizes an increase ...
(Date:10/11/2017)... ... 2017 , ... A new study published in Fertility and ... in vitro fertilization (IVF) transfer cycles. The multi-center matched cohort study ... comparing the results from the fresh and frozen transfer cohorts, the authors of ...
(Date:10/10/2017)... ... 2017 , ... For the second time in three years, ... Award. Representatives of the FirstHand program travelled to Washington, D.C. Tuesday, October 10th, ... mission is to change the trajectory of STEM education in America by dramatically ...
Breaking Biology Technology: