A study led by Princeton biologists has revealed a remarkably simple mechanism that allows flocking birds, schooling fish or running herds to travel in unison without any recognized leaders or signaling system. The finding, published in the Feb. 3 issue of Nature, helps settle age-old questions about how animals coordinate their actions. Previously, scientists had looked for subtle signals or other explicit systems that animals may use in disseminating information through groups. The new study showed that such complexity is not necessary: Large groups easily make accurate decisions about where to go even when no individuals are regarded as leaders and very few individuals have any pertinent information. In addition to shedding light on the graceful coordination of animal groups, the results may be useful in understanding how humans behave in crowds and in designing robots that explore remote locations such as the ocean or other planets. "When you see apparently complex behaviors, the mechanisms that coordinate these behaviors may be surprisingly simple and generic," said Iain Couzin, a postdoctoral researcher in Princeton's Department of Ecology and Evolutionary Biology and lead author of the study.

Related chapters from BP6e: Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 15: Language and Our Divided Brain
Link ID: 6808 - Posted: 02.04.2005

By HENRY FOUNTAIN Homing pigeons are renowned for their ability to navigate over long distances, and after decades of study scientists are pretty sure they know how the birds do it. They use their sense of smell to figure out where they are and the position of the sun to determine the direction they must fly. But less is known about how pigeons navigate when they are close to home, in more familiar surroundings. Many researchers have thought that in such situations the birds must rely, at least partly, on visual cues. "There's been controversy about whether familiar landmarks have been used," said Jessica Meade, a doctoral student in the Animal Behavior Research Group at the University of Oxford in England. "Because there was no tracking of the birds along the homeward route, the hypotheses aren't very clear." Ms. Meade and two colleagues, Dr. Dora Biro and Dr. Tim Guilford, set out to rectify that situation, using small Global Positioning System loggers attached to the backs of 15 homing pigeons. These devices, which weigh about an ounce, use satellite signals to record precise location fixes every second. The researchers released the birds about three miles from home, and each bird had about 20 flights from the same point. The results are published in Proceedings B, a journal of the Royal Society. Copyright 2005 The New York Times Company

Related chapters from BP6e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 6713 - Posted: 01.18.2005

Using satellite tracking to study the paths pigeons take on homeward-bound journeys, researchers have obtained strong new evidence to support a long-held theory: in some environments, pigeons instinctively learn to follow major roadways in navigating their flight. The new findings are reported by a research group headed by Dr. Hans-Peter Lipp of the University of Zürich. Anecdotal evidence from breeders of racing pigeons as well as initial aerial tracking studies together suggested that pigeons may follow roadways and use highway landmarks as turning points in their flight. However, the challenge of accurately tracking the birds stood in the way of solid quantitative analysis. In the new work, miniaturized GPS "flight-loggers," which pigeons carried on their backs, allowed researchers a clear and reliable picture of the birds' flight paths. Over three years, the researchers analyzed more than 200 flight paths of 20-80 km in length made by pigeons travelling toward their home loft from numerous release sites located in the general vicinity of Rome, Italy. They found that, when released from familiar sites, pigeons with homing experience were significantly attracted to highways and a railway track running in the approximate directions home. When these structures began to veer significantly from the beeline to the loft, some birds tended to break away and head in a more homeward direction, but others took a detour by following the highway until a main junction, at which point they followed a valley road in the direction of the loft.

Related chapters from BP6e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory, Learning, and Development
Link ID: 5888 - Posted: 07.27.2004

As dusk settles across the Belfast skyline, Joe Neeson whistles and calls down his racing pigeons. Joe doesn't count - he doesn't need to. After years looking after his tiny loft in the yard behind his west Belfast home, he knows every bird by name. So when Joe scanned the roof above the loft on the day of Linda's first race, he knew there was a bird missing. The young pigeon had been released more than 300 miles away in Penzance. And as darkness fell, Joe knew that Linda was not coming home. Seven hundred miles away across the North Sea, Linda was beginning what would be a year-long adventure. No-one knows for sure how Linda arrived at the petrol refinery at Mongstad - one of Europe's biggest ports. It seems likely though that the exhausted pigeon "jumped ship" in the fading light as she flew across the North Sea. Refinery workers found her cowering under clothes lockers and took pity on the bird which seemed close to death. A Norwegian television crew was at the refinery to record a wildlife film, and journalist Hans Gunnar Skarstein realised that the band on the pigeon's leg held the key to her identity. (C)BBC

Related chapters from BP6e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 5856 - Posted: 07.21.2004

Nature article reports photoreceptors involved in sensing the earth's magnetic field Migratory birds, as well as many other animals, are able to sense the magnetic field of the earth, but how do they do it? "A fascinating possibility is that they may actually see the earth's magnetic lines as patterns of color or light intensity superimposed on their visual surroundings," said John B. Phillips of Blacksburg, associate professor of biology at Virginia Tech. The results of more than two decades of research allow him to let such an image cross his mind. A paper in the May 13 issue of Nature, "Resonance effects indicate a radical-pair mechanism for avian magnetic compass," reports evidence that the earth's magnetic field is sensed by light-absorbing molecules in the retina of a bird's' eye. Any effect of the earth's magnetic field on a photoreceptor's response to light is expected to be extraordinarily weak -- so weak in fact that the possibility of such effects have been largely ignored. But animals have developed specialized visual systems. "Some animals can see ultraviolet light. Some animals can see polarized light," Phillips said.

Related chapters from BP6e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 7: Vision: From Eye to Brain
Link ID: 5470 - Posted: 05.14.2004

Homing pigeons are finding their way around Britain by following roads and railways, zoologists claim. They say the birds' natural magnetic and solar compasses are often less important than their knowledge of human transport routes. A 10-year Oxford University study discovered some pigeons turn off at certain motorway junctions and use landmarks to remember where they are. The scientists behind the study were "knocked sideways" by their findings. The pigeons' routes were mapped to within four yards by tiny tracking devices and global positioning system technology. Research team member Dr Tim Guilford said the results were "plain to see". "They don't follow linear lines all the time and sometimes when they're flying at 200 or 300ft above built-up areas it's difficult to see exactly what they are following. (C) BBC

Related chapters from BP6e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 4935 - Posted: 02.08.2004

Fears are growing for the safety of a rare bird of prey which got lost at sea while making a record migration from Scotland to Africa. The young honey buzzard, which only learned to fly a month ago, went off course after it was caught in difficult weather conditions over the Atlantic. A satellite tracking system estimates that it has made the longest flight ever recorded by a bird of prey and was in the air for more than 100 hours during a journey in excess of 5,000 kilometres. However, concern about the fate of the bird is growing among conservationists and enthusiasts who have been following its progress over the internet. Two honey buzzards were being tracked as part of an attempt to learn the mysteries of their migration south. The Forestry Commission and the Highland Foundation for Wildlife teamed up to follow their journey. (C) BBC

Related chapters from BP6e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 2745 - Posted: 10.01.2002

Philippine researchers want to restore a sea snake that has been wiped out on Gato Island by translocating the species from other islands. But new research suggests that this may not work because these snakes have such a strong drive to return to their own islands. "The fidelity of snakes to their home island was absolute," say Sohan Shetty, then at the University of Sydney, Australia, and now at Nanyang Technological University in Singapore, and Richard Shine of the University of Sydney, Australia, in the October issue of Conservation Biology. Widely distributed in the Pacific Ocean, the snakes (yellow-lipped sea kraits) forage for moray and conger eels in the ocean, and typically return to land to digest their prey, mate, lay eggs. The up to 5-foot long snakes are prized for their meat and skins, which are used to make high-quality leather goods, and are easy to catch in huge numbers because they are concentrated on small islands and, although venomous, are so docile that they rarely bite or even try to escape.

Related chapters from BP6e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 2704 - Posted: 09.25.2002

By NATALIE ANGIER Midway through a honeybee's fleeting, bittersweet, and, yes, busy little life, a momentous transformation occurs: the 2-week-old worker must abandon her cloistered career as a hive-keeping nurse, and venture out into the world to forage. She must learn to navigate over great distances at 12 miles per hour, select the finest flowers, assemble bits of pollen and droplets of nectar into a load nearly as heavy as she is, and then find her way back home. Once there, she must convey the coordinates of her discovery to her sisters in the classic cartographic waggle, the bee dance. And all this behavioral complexity is packaged in a brain no bigger than the loop of a letter b printed on this page. Copyright 2002 The New York Times Company

Related chapters from BP6e: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 2020 - Posted: 05.07.2002

Emma Young Migrating birds use changing magnetic fields to tell them when to stop and eat, say Swedish researchers. The team exposed eight caged thrush nightingales to a magnetic field simulating a six-day journey from Sweden to northern Egypt, where wild birds stock up on food prior to crossing the Sahara desert. For a further five days, the birds were kept in "magnetic Egypt". Eight control birds were caged in a lab free from artificial magnetic fields. Both sets of birds had free access to food. Thord Fransson of Stockholm University and his colleagues found the experimental birds increased their eating between days six and 11. Journal reference: Nature (vol 414, p 35) © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 13: Homeostasis: Active Regulation of Internal States
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 906 - Posted: 11.02.2001