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New Technology Allows Researchers To Accurately Monitor Avian Social Networks

September 21, 2012
Image Caption: A study led by St. Andrews University in Scotland tagged New Caledonian crows to learn about their social behavior. Credit: C. Rutz, St. Andrews Univ.

Alan McStravick for redOrbit.com – Your Universe Online

It seems each day our world is introduced to a new piece of technology that makes our day-to-day lives just that much easier. So, it should only make sense that we would see advancements even for the seemingly most mundane of research methods.

“This is a new type of animal-tracking technology,” said Brian Otis, a University of Washington associate professor of electrical engineering whose lab developed the tags. “Ecology is just one of the many fields that will be transformed with miniaturized, low-power wireless sensors.”

The long-standing method used previously involved a radio transmitter, attached to the animal, which could only be monitored if the researchers were nearby or following the animal, herd or flock with a VHF receiver. Think of it as a very low frequency radio station. While effective in tracking the grazing, migration and mating patterns of their subjects, researchers were limited in their ability to observe each and every interaction. As night falls or the subject disappears under fauna or foliage, there was no certainty as to what may actually be occurring.

This new electronic tag, designed at the University of Washington, can, for the first time, see when birds meet in the wild. Not only are the tags smaller than previous tags, (the smallest weighs approximately 1 gram), but the tags are attached to the birds with a degradable strap that separates from the subject only after the battery dies. Plus, the tags interact with other tagged animals showing, in real time, how each animal interacts with the other. Researchers are also able to reprogram the tags remotely. This feature would allow the researchers to view the initial results to see when there are few encounters happening, and turn the battery off during those times to conserve power.

Encounternet, a telemetry system that combines animal worn digital radio tags and rugged wireless base stations, is the name given to the University of Washington tracking tag system, which was developed with funding from the National Science Foundation by co-authors Drs. Brian Otis and John Burt.

Burt, speaking on the system, commented, “Encounternet tags can monitor each other, so you can use them to study interactions among animals. You can´t even start to do that with other radio-tracking technology”

Burt, whose doctorate was completed after a dissertation on birdsong communication and learning, wanted to see if there was any possible way to monitor bird interactions in the wild. He partnered with Otis, an expert in small, lightweight, low-power electronics. After nearly 7 years of development, the pair founded Encounternet LLC, based out of Portland, OR. Future iterations will incorporate a GPS component to record the location of the encounters. Additionally, an accelerometer and other sensors could aid in detecting the behavior of the animal.

“People are excited about this because for the first time, it allows them to study smaller animal interactions and social networks on an incredibly fine scale,” Burt said. “Social networks are turning out to be key to understanding many animal behaviors. People say Encounternet is the only thing they can find that can collect that information.”

And excited, they are. A study performed by a biologist at Scotland´s University of St. Andrews used the new technology to observe New Caledonian crows and their learning behaviors, with respect to the use of tools. The New Caledonian crow is renowned for their use of different tools to extract prey from deadwood and vegetation. The study leader wanted to ascertain if the birds might learn this behavior by watching other crows. The theory was supported and the findings published in Current Biology. In fact, the exceptionally high level of social mobility was unexpected. Many of the birds spent a significant amount of time near birds that were not part of their immediate families. During one week in particular, the Encounternet tags were able to record more than 28,000 interactions among just 34 New Caledonian crows. As the core family unit of this crow consists only of 3 members, the study showed that all of the birds were connected via a larger social network. This is the first published study that utilized the Encounternet tags to record animal social interactions.

While the University of St. Andrews may have been the first to publish data collected using this new technology, several other research groups are currently using the tags for their own studies. The University of Windsor in Ontario, Canada is using them to study mating behavior of Costa Rican long-tailed manikins. At Drexel University in Philadelphia, PA, a researcher is using Encounternet tags to observe interactions between birds and army ants in Costa Rica. In the Galapagos Islands, German researchers are utilizing the tags to study the behavior of sea lions as they make landfall. And in the Netherlands, researchers are finding their study of the social behavior of great tits, a small woodland bird, aided invaluably by the new technology.

The development of these new, lighter tags, and of Encounternet LLC, has been a labor of love for Burt. “It´s a big topic right now, the idea that animals have social networks,” he said.  Burt, himself, has been assisting field biologists for the last three years to deploy the new tags.

It is now, through the work of these and other research teams, widely believed that all societies, human and animal, can be viewed as networks of interconnected individuals, linked by social, spatial, temporal and other relationships. With this new ability to study a network structure, we will be able to obtain unique insights into the inner workings of the society, allowing us a better understanding of the behavioral strategies that individuals use to enhance their success.

While social network analysis has been extensively developed and used for studying human societies and behavior, animals are also social creatures. One of the problematic aspects of studying an animal´s social network, prior to the unveiling of this technology, was that animals tend not to share with you where they have been and with whom they have interacted. This information is vital to the study of a social network. Encounternet makes the continuous study of a population possible.

“There are other tags that can do proximity logging, but they´re all very big and for larger animals.  None is as small as Encounternet — or even near to it,” Burt concluded.


Source: Alan McStravick for redOrbit.com - Your Universe Online