NEWS : TECH (NFPC)

Digital Sound Tech Used To Study Rare Owls

Digital sound systems have moved from the living room to the forest. In Yosemite, Calif., researcher are using digital mp3 recorders to used to study a rare species of great gray owl.

Trapping and banding them is traumatic for the birds, and the Joe Medley, a PhD candidate in ecology at the University of California, Davis, wanted to find a way to avoid that. So Medley decided to use digital audio recorders to pick up the owl's calls.

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The recorders are called Autonomous Recording Units (ARUs) are powered by batteries and have two-high gain microphones. The ARUs are put inside waterproof cases and hung off of tree branches. They can record for about two weeks at a time. The particular ones Medley used were purpose-built, but there are commercial versions available, he said. (The detectors are only six to eight feet off the ground, so no tree-climbing was needed).

At first he ended up with 50 terabytes of owl calls mixed with background sounds. So the next step was to tease out the owls' calls. That required sophsticated software, Medley told Discovery News. It's called Raven Pro, developed by the Cornell University Laboratory of Ornithology. Medley had to write the owl-specific parts of the program himself, though. The algorithm he developed searched recording data for a certain amplitude -- essentially, the amount of energy in the sound -- within certain times and frequencies.

"The detectors are very good at detecting target signals, but also detect a lot of false positives, so we had to develop a secondary processing method where we used a classifier (using a statistics program) to differentiate actual owl calls," Medley wrote in an email. 

The program could ultimately pick out males and females from juveniles, and even identify nesting females calling for food. The results are still being analyzed.

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Great gray owls are the largest owls in North America, and the ones in Yosemite are a subspecies that split off from their cousins relatively recently -- during the last ice age, about 30,000 years ago. Great gray owls generally are more common, with a range that extends through much of Canada and the taiga forests in Asia. But the group in Yosemite seems to be a genetically distinct population. They also have differences in behavior such as where they build nests, migrate and what they eat. Only about 200 still exist today, and they face threats from humans such as habitat destruction.

Medley added that while owls have relatively low-frequency calls, the technology could also be applied to other animals as well, such as frogs, that have distinctive noises. The methods would be the same -- the only difference would be what the software is programmed to pick up.

Credit: National Park Service / Joe Medley

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Robot Spies On Sharks

Observing sharks in the wild isn't always the easiest thing to do. Sharks can be tagged and tracked via satellite, but that information gives a mostly two-dimensional view of where the fish has come from and where it's going. Now a group of researchers at the University of Delaware has turned to an underwater robot to observe sharks.

The robot is called the Oceanographic Telemetry Identification Sensor, or OTIS. Shaped like a torpedo, it tracks previously tagged sharks -- specifically, sand tiger sharks, stealthily over the course of several days.

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Ordinarily OTIS is used to sample water conditions, but this time it was fitted with receivers to pick up the signals from the shark tags. Since OTIS is remote-controlled, it can be sent to follow a shark and report back in real time, giving a much clearer picture of where the animals travel.

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OTIS meanwhile, will help the scientists figure out what kind of water conditions sharks like to swim in during their travels. The robot will test the temperature, clarity and oxygen levels. This too could offer insight into behavior -- and also how to protect the sharks. The species is listed as "vulnerable" by the International Union for the Conservation of Nature.

Eventually the information could be combined with other data gathered from other shark-tracking technology. One type of tag transmits its location while listening for the "pings" from other sharks tagged with the same device. That means scientists can see not only where a shark is but how many of her fellows are nearby. This offers insight into sharks' social behaviors and the location of their habitats.

Credit: Evan Krape / University of Delaware

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Spider Webs Inspire 'Bird Safe' Windows

A glass inspired by spider's webs is being used to keep birds from smacking into windows.

Birds can't see glass well, and so many of them die when they hit picture windows. Humans can't see glass well either, which might explain why some people try to walk through glass doors. But most people know that the refection of the sky and landscape in a window isn't real -- unfortunately, birds don't. According to the Fatal Light Awareness Program, a building with glass walls or windows can kill up to 10 birds per day, and estimates of worldwide deaths from such collisions reach hundreds of millions of birds each year.

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On Lindisfarne Island, off the northeastern coast of England, local authorities wanted to do something about it. Hundreds of species of migratory birds pass through every year. So officials decided to cover a lookout tower with glass designed by Arnold Glas, a German company. Called Ornilux, the glass has a spiderweb-like pattern that humans can't see unless they stand very close (see image below, right). But because glass reflects ultarviolet light, birds can see the pattern very well.

Spider webs, particularly those of orb weaver spiders, work the same way, reflecting UV and alerting the bird that there is something there. While flying through a web wouldn't hurt a bird, the bird doesn't know that. So they avoid them.

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The glass was tested in a flight tunnel in the United States. Birds were allowed to fly to one end of the tunnel which was covered with two types of glass, one with the UV-reflective coating. The birds avoided hitting the coated glass up to 68 percent of the time. (No birds were hurt in the testing because researchers used a net to prevent the birds from impacting the glass.)

The glass is also being used by a Canadian wildlife center, a German zoo and a mountain railway building in Austria.

 via Physorg

Credit: Wikimedia Commns / Austin Marshall

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Old Genes Make New, Giant-Headed Ants

Every animal carries a record of its past in its genes -- sometimes teeth show up in birds and vestigial limbs on snakes and whales. Ants are no exception. What if that potential could be tapped? And what brings it out?

That’s what a group of scientists at McGill University thought when they ran into a colony of ants on Long Island. A colony of ants known as Pheidole morrisi (more commonly called big-headed ants) had members we call soldiers with really outsized heads and bodies. These were called “super soldiers.”

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Pheidole, like many other ant species, are divided into castes, such as workers, queens and soldiers. Different foods are given to them when they are larvae, which triggers hormones that determine which caste the ant grows up to be.

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Super soldiers occur naturally in some species of Pheidole in the southwestern United States and Mexico. But those living in upstate New York aren’t supposed to have the big heads. Ants are a pretty diverse lot and there are more than 1,100 species within even the Pheidole genus. But only eight of them naturally produce the super soldiers.

Biology professor Ehab Abouheif and PhD student Rajee Rajakumar wondered if the genes that build super soldiers were present in the Long Island ants all along, but were just waiting for some environmental factor to bring them out. The scientists first went to Arizona and collected two other species of ant in the same genus, Pheidole rhea and Pheidole obtusospinosa, which both have a subclass of super soldiers. They then observed how those two species developed their super soliders.

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Next, the scientists gave the young Long Island ants juvenile hormones at certain specific points in their development. In the Pheidole morrisi they got the super-soldier ants, which showed that the potential was always there. It just needed something to bring it out. One interesting phenomenon was the super soldiers had wing buds, which their cousins from Arizona did not. Many ant species develop wings as part of their development and ants and wasps share a common ancestor. The procedure worked in three different species of Pheidole, even though all three were separated by thousands of miles and millions of years of evolution.

Previously, few biologists thought such ancestral traits were important. They were just leftovers like the stuff in your attic. This shows that when necessary, nature has a “tool kit” that it can use to create big morphological changes -- some of them new.

Via: McGill University

Image: Alexander Wild

 

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Tech Sees Fire Where There's Smoke

Wildfires that produce a lot of smoke are difficult to manage because the source of fire can be hard to see. From the air, firefighting units typically use infrared cameras to help spot the hottest and most intense parts of a fire. But when conditions are far to dusty and smokey, the infrared technology is not effective.

Researchers at Fraunhofer Institute for High Frequency Physics and Radar Techniques in Wachtberg, Germany, have developed a sensor that can see through the smoke. It works at a much lower frequency than the infrared sensors, and is less affected by dust particles. It can also see down through thick foliage to locate hidden areas of fire.

"Particles of dust and smoke are practically transparent in the microwave range, but the radiation is still strong enough for the source of a fire to be detected," said team leader Nora von Wahl. "From a height of 100 meters, we were able to locate fires measuring five meters by five meters in low visibility conditions,” she said.

The system is also quite effective for locating fires that are smoldering beneath the top layer of earth -- a problem that occurs with wildfires thought to have been snuffed out.

Photo: George Frey-Pool/Getty Images

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