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.firstname.lastname@example.org
Jeff Grabmeier | Newswise Science News
Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute
'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences