Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Learning how to help migrating swans find forage

02.05.2007
Do foraging decisions tell us something about the cost of foraging? Dutch swan experts at the Netherlands Institute of Ecology (NIOO-KNAW) were interested in the apparent heterogeneity in the use of agricultural fields by migratory Bewick’s swans.

In Wieringermeer, a typical Dutch polder that was reclaimed from the sea in 1930, Bewick’s swans stop by during migration to feed on the leftovers of sugarbeets that remain after the farmer’s harvest. The ornithologists were interested in why some fields were used more intensively than others, while all fields seem to offer similar amounts of food right from the start.

They wondered: "In case foraging benefits seem to be equal across all fields, there may be variation in foraging costs that may explain the observed spatial heterogeneity in exploitation." The authors showed, in the May issue of the American Naturalist, that the time spent feeding on a field by a flock of swans can be used as a surrogate of an individual’s energy intake rate (which declines over time due to depletion). This showed that an individual’s intake rate at abandoning a field, which should reflect the foraging cost as experienced by the bird itself, decreased with the distance to roads and increased with the distance to its nighttime roost.

The higher intake rates at which fields near roads were given up reflected the chance to be disturbed by humans. The higher intake rates at which fields far from roosts were given up could be explained by the energetic cost of flight, which are substantial for large birds such as Bewick’s swans. When taking these flight costs into account, the authors calculated that the net benefits at which each field was given up corresponded with the net benefits obtained in the long run. The latter was measured via regular visual inspection of the thickness of each bird’s belly!

All these insights into foraging costs could be implemented into a model that predicted the number of swans that potentially could stop by at the site. This model accurately and correctly predicted the true number of birds that made use of the stopover. It could thus serve as a valuable tool to manage and protect the relatively small population of Bewick’s swans wintering in NW Europe, which declined from 30,000 to 20,000 birds over the last 15 years.

Patricia Morse | EurekAlert!
Further information:
http://www.uchicago.edu

More articles from Ecology, The Environment and Conservation:

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>