By studying American redstarts, National Zoo scientists have shed light on the phenomenon that has important implications for rates of genetic differentiation. The study was published online in the Feb. 18 issue of the Proceedings of the National Academy of Sciences USA.
Scientists looked at two distinct redstart habitats in Jamaica—one, a lush, food-rich habitat, and the other, a dry and harsher habitat. The study showed that birds that spent their first winter in the lush habitat left earlier for spring migration and traveled relatively short distances to breed. Birds that first wintered in the harsher habitat left later on migration and traveled a longer distance to breed.
The difference in migration distance between birds in these habitats led to birds from the lush habitat dispersing south of their hatch site and birds from the dry, harsh habitat dispersing north of their natal site.
Studying natal dispersal in migratory birds has previously presented a challenge to scientists. It is difficult to track small animal species across long distances as opposed to larger animals that can be fit with satellite collars.
Scientists Colin Studds, a doctoral candidate in the Program in Behavior, Ecology, Evolution, and Systematics at the University of Maryland (College Park), and Peter Marra, an ecologist at the Migratory Bird Center, investigated this phenomenon.
They compared a chemical marker in the feathers of birds spending their first winter in Jamaica to the feathers they grew one year later after their first breeding season. This marker—a stable isotope of hydrogen—revealed the approximate latitude in North America where birds grew their feathers. Hydrogen isotopes vary predictably with latitude, and birds store the signature of their local area in their bodies through their insect-rich diets. By sampling redstart feathers in Jamaica, the researchers were able to piece together the hatching and breeding latitudes of birds they could not otherwise track for long distances.
Natal dispersal is thought to be the main process affecting genetic mixing of bird populations. This study is first to show that conditions in tropical winter areas can influence natal dispersal patterns. The findings underscore the importance of developing conservation projects that take into account the annual cycle of a migratory bird.
John Gibbons | EurekAlert!
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University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
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Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
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Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
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