Science News
Estrogenic chemicals change birds' tunes
Wild birds sing more complex melodies when exposed to endocrine disrupters.
Both natural and synthetic chemicals that mimic estrogen can change how male birds sing by enlarging sections of their brains responsible for creating songs. Researchers have taken these findings to the field for the first time, showing that the more complex songs these birds sing attract more females. But the males' immune systems and their overall reproductive success may be compromised by exposure to the contaminants.
Reporting in PLoS ONE (2008, DOI 10.1371/journal.pone.0001674), researchers led by Katherine Buchanan of Cardiff University (U.K.) describe their experiments with several dozen starlings. The team housed 35 young male birds in outdoor aviaries over several winter months, when the starlings would normally have fed on worms from sewage treatment plants. The birds fed instead on worms the researchers had spiked with environmentally relevant doses of 17-β estradiol or with a hormone cocktail containing 17-β estradiol, dioctyl phthalate, bisphenol A, and dibutyl phthalate. A control group received no hormones.
Birds that ate contaminated worms for several months sang the longest and most varied songs; they also spent the most time singing and their brains had larger higher vocal centers. The starlings that were fed worms containing only 17-β estradiol were close behind. But the song performances of the control group lagged; they spent less time singing, with fewer and less varied tunes in their repertoires. Female starlings that listened to recordings of the songs lingered next to the speakers longer during songs of male birds fed the hormone mixture.
Despite their increased singing prowess, the exposed males' immune responses faltered in basic tests compared with those of control group males. The researchers hypothesize that the females' choice to mate with less fit males could explain recent decreases in starling populations in Europe—and have implications for other species as well.
Many studies have been published on the mechanisms of hormone effects on birds, comments Mary Ann Ottinger of the University of Maryland, but this study takes the next step toward a better understanding of how contaminated prey might affect birds' behavior in the wild.
Science
Luring bats to jump-start tropical reforestation
Providing artificial roosts for bats could pave the way to reseeding devastated forests, researchers say.
Repaired ozone hole will warm Antarctic
The ozone hole helps shield the interior of the Antarctic from global warming's effects—but once it is healed, the continent could catch up quickly with the warming trends of the rest of the planet.
Metal pollution is toxic for endangered eels
New research finds that cadmium acts as an endocrine disrupter in European eels during their 6000 kilometer migration.
Searching for data on GMOs
Researchers call for greater monitoring of genetically modified crops.
Sunny year sped Arctic ice melt
As Arctic sea ice shrinks, it becomes more vulnerable to sunny weather.
Technology
Would you like that book in paper or plastic?
Electronic book readers save paper, but can a piece of plastic really be better for the environment? ES&T reporter Erika Engelhaupt is determined—very determined—to find out.
Removing salt to supply a nation's water
Desalination technologies currently provide less than half a percent of the U.S. water supply, but that amount may increase, according to a National Academy of Sciences report.
A renewable route to green gasoline
Because they are more attractive to the petroleum industry, "next-generation" biofuels produced from renewable feedstocks may have a brighter future than ethanol.
Plugging in to more water use
A big shift to electric vehicles could strain water resources in dry places.
Policy
ES&T Comment: An agency in crisis
Sometimes an intervention is needed to save an old friend, to convince them to change their destructive ways. That's how I feel about the U.S. EPA. [Pictured, William Ruckelshaus, courtesy of the U.S. EPA.]
Wiping nature's hard drive
A new book explains how human health will suffer from a decline in biodiversity as potential medicines are lost and food production takes a hit.
Panel urges reform of factory farms
A Pew Commission report says health and environmental risks of industrial farms outweigh their cost savings.
A new survey reveals a lack of resources and training among public-health workers to respond to health problems related to climate change.
European court bans widely used flame retardant
The EU has banned the Deca BDE flame retardant for the second time.
Business & Education
U.S. manufacturers spent $26 billion on pollution abatement in 2005, according to a government survey.
The scientist's work tallied the invisible water used to make food and other products.
ES&T Associate Editor Dzombak named to NAE
Dzombak is cited for his novel development of models used in evaluating chemical behavior in water-quality engineering and environmental remediation.
A new report shows a rising trend in the number of eco-friendly buildings in the U.S.
