A Logical Step

bird sowerbyJames Sowerby (1757 – 1822)
A Bird with Wings Spread

Ithaca, N.Y.
—It may not kill them outright, but low-level PCB contamination is disrupting the way some birds sing their songs. So conclude the authors of a seven-year Cornell University study published today in the science journal PLOS ONE.

Before the chemicals were banned in the United States in 1979, polychlorinated biphenyls, or PCBs, were widely used in the manufacture of electrical devices because they can withstand extremely high temperatures.

“PCBs are changing behavior in subtle but important ways that we’re only beginning to recognize,” says lead author Sara DeLeon. “The Black-capped Chickadees and Song Sparrows we studied ingest PCBs when they eat contaminated insects. The chemicals appear to mimic hormones and interfere with development in the part of the bird’s brain that governs song and song structure.”

Key among the findings is that song disruption is tied to specific types of PCBs—there are 209 variations, differentiated by the positioning and number of chlorine atoms. DeLeon tested 41 of these variations to isolate their effects.

DeLeon chose five study sites in New York State, including two along the Hudson River that were heavily polluted by PCBs dumped illegally from 1947 to 1977. The other sites were not known to have PCB contamination and tests at an Adirondack Mountains site eliminated mercury as a factor in song changes. At each site she collected and tested blood samples from males of the two bird species, recorded their songs over several field seasons, and analyzed those songs.

“The songs of Black-capped Chickadees and Song Sparrows are very well studied,” DeLeon says. “For example, we know that it’s normal for there to be very, very little variation in the way all Black-capped Chickadees deliver their fee-bee song and the interval between the two notes.
We found the greatest variation among birds in areas with higher levels of certain types of PCBs—their songs just were not coming out right. Since dominant males produce the most consistent songs, this variation could have important biological consequences.”

“Effects of PCBs are extremely complicated,” says co-author André Dhondt, director of Bird Population Studies at the Cornell Lab of Ornithology. “What this demonstrates is that most previous PCB studies may not give us the whole picture because they did not look at the specific type of PCB involved but just measured overall levels.”
It took about three years just to complete the chemical analyses.

The next logical step, Dhondt notes, would be to use this method to study low-level PCB effects elsewhere to learn how the pollutants are being spread through ecosystems and the effects they could be having.

 

Other co-authors include research associate Ralph S. Hames; assistant professor of ecology and evolutionary biology André Kessler; and Timothy DeVoogd, professor of psychology, all from Cornell.

 

http://www.news.cornell.edu/stories/2013/09/even-low-level-pcbs-change-bird-songs

This study was funded by: New York Sea Grant; Cornell University Biogeochemistry and Environmental Biocomplexity Small Grant; Cornell Travel Grant; Mellon Grant; Kieckhefer-Adirondack Grant; State University of New York Fellowship;  SLOAN Fellowship; and a Tibor T. Polgar Fellowship.

Is Grammar Unique to Human Language?

the strawberry thief
While birdsong has long been known to share similarities with human language, the ability to convey different bits of information by simply rearranging word order was thought to be exclusively human.

This study revealed that Bengalese finches can learn grammar and, furthermore, that their grammatical abilities involve a specific part of the brain region distinct from other brain regions involved in singing. This is similar to what neuroscientists understand about human language processing.

If the tweets of birds can be roughly likened to strings of human words, and if bird brains process songs in a way similar to how human brains process language, future research may tackle whether these animals possess other cognitive abilities once thought to be singularly characteristic of human intelligence.

About the Author: Danielle Perszyk is a social neuroscience researcher at the Yale Child Study Center, where she studies autism using electrophysiological methods. At Williams College, studying cognitive science and neuroscience, she wrote a thesis on the neural mechanisms underlying syntax in birdsong. She is interested in the mind from an evolutionary perspective and is pursuing her PhD in cognitive psychology.

http://blogs.scientificamerican.com/guest-blog/2011/10/28/are-birds-tweets-grammatical/

Strawberry Thief is one of William Morris’s most popular repeating designs for textiles. It takes as its subject the thrushes that Morris found stealing fruit in the kitchen garden of his countryside home, Kelmscott Manor, in Oxfordshire. To print the pattern Morris used the ancient and painstaking indigo-discharge method he admired above all forms of printing.

Lyrebirds – Accidental Historians

Archibald James Campbell 1853-1929. Silver gelatin print.

Nature’s Living Tape Recorders May Be Telling Us Secrets
Robert Krulwich

In 1969, Neville Fenton, an Australian park ranger, recorded a lyrebird singing a song that sounded very much like a flute, a flute being played by a human. After much sleuthing, Mr. Fenton discovered that 30 years earlier, a farmer/flute player had lived near the park and played tunes to his pet lyrebird. That lyrebird downloaded the songs, then was allowed to live wild in the park.

Phrases from those flute songs apparently became part of the local lyrebird songbook. A scholar named Norman Robinson figured out that the songs wild lyrebirds were singing in 1969 were modified versions of two popular tunes from the 1930s, “The Keel Row” and “Mosquito’s Dance.”

When the BBC’s David Attenborough ran into a lyrebird deep in the Australian woods, the bird not only sang the songs of 20 other forest birds, it also did a perfect imitation of foresters and their chainsaws, who apparently were getting closer. That same bird made the sound of a car alarm.
These birds were, in effect, recording the sounds of their own habitat destruction.

http://www.npr.org/blogs/krulwich/2011/04/26/135694052/natures-living-tape-recorders-may-be-telling-us-secrets?ft=1&f=1007