Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Bright Red of Cardinals Means Less in Urban Areas

02.09.2010
Normally, the brilliant red of a male cardinal signals to females that he is a high-quality mate. But that may not be true of cardinals living in urban areas, a new study suggests.

Researchers found that the bright red feather coloration of male northern cardinals (Cardinalis cardinalis) was less related to body condition for birds living in urban forests than it is for those in rural forests. In other words, even cardinals in relatively poor condition may appear bright red in urban areas.

“We found that the relationship between brightness and body condition was stronger in more rural landscapes than it was in urban areas,” said Amanda Rodewald, co-author of the study and professor of wildlife ecology at Ohio State University’s School of Environment and Natural Resources..

“That means urbanization has the potential to disrupt cues that birds have long used to assess quality and choose mates.”

Rodewald conducted the study with Todd Jones, an undergraduate student researcher at the time, and Daniel Shustack, a recent doctoral graduate. Their results appear in the current issue of The Wilson Journal of Ornithology.

The researchers studied 129 male and 145 female cardinals that were captured in 13 forests in central Ohio between 2006 and 2008. Each forest was rated as to the amount of urbanization surrounding it, and the researchers compared feather samples from cardinals at each site.

The feathers were photographed and the photos were analyzed by a software program that measured the hue, saturation and brightness of each feather.

They also measured body mass and size of the cardinals to indicate their body condition, or health. Body condition considers how much a bird weighs after adjusting for its frame size.

The researchers did not find any relation between female body condition and plumage brightness and whether they lived in a more urban or more rural area.

For males, brighter feathers were indicative of birds in better condition in rural areas, but were not as indicative in urban areas.

In cardinals, as in some other birds, feather coloration is related to their diet. Diets high in carotenoids – pigments found in some fruits and other parts of plants – lead to brighter feather colors.

Previous studies indicate that forests within urban areas have nearly three times the amount of fruit and nearby bird feeders than exist in rural areas. Urban forests have many exotic and invasive species, such as Amur honeysuckle and multiflora rose, that provide abundant sources of carotenoid-rich fruits.

The fact that carotenoid-rich fruits are more available in urban areas, to birds over a wide range of conditions, may be one reason that brighter feathers aren’t more indicative of healthy birds in urban areas, Rodewald said. In rural forests, only the highest-quality individuals may have access to carotenoids.

Rodewald is continuing this research by studying how plumage coloration is related to the quality of territories that birds secure and their ability to produce young.

The research was funded by the National Science Foundation, the Ohio Division of Wildlife, Schwab Associate Scholarship grant from The Ohio State University, and an undergraduate research grant from the College of Biological Sciences.

Contact: Amanda D. Rodewald, (614) 247-6099; Rodewald.1@osu.edu
Media Contact: Jeff Grabmeier, (614) 292-8457; Grabmeier.1@osu.edu
Written by Jessica Orwig

Jeff Grabmeier | Newswise Science News
Further information:
http://www.osu.edu

More articles from Life Sciences:

nachricht Researchers discover specific tumor environment that triggers cells to metastasize
22.11.2017 | University of California - San Diego

nachricht New discovery: Common jellyfish is actually two species
22.11.2017 | University of Delaware

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Researchers at IST Austria define function of an enigmatic synaptic protein

22.11.2017 | Life Sciences

Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes

22.11.2017 | Materials Sciences

Women and lung cancer – the role of sex hormones

22.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>