sust-mar: Loons "mad as a hatter" from mercury

Date: Tue, 12 Jan 1999 14:06:40 -0400 (AST)
From: "David M. Wimberly" <ag487@chebucto.ns.ca>
To: Sustainable-Maritimes <sust-mar@chebucto.ns.ca>
Precedence: bulk
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     _________________________________________________________________
                                      
       Tuesday, January 12, 1999
       Rising mercury hurts loons
       Tailpipe of North America receives `warning'
       By David Swick

       THE CRY OF LOONS, a new report by two Acadia
       University biologists suggests, might be a cry for help.
       Graduate student Joe Nocera and professor Dr. Phil Taylor say loon
       chicks in Kejimkujik National Park and southern New Brunswick are
       demonstrating unusual behaviour. It's a sign, they believe,
       mercury poisoning is impairing the loons' nerve functioning.
       "This is a warning," Nocera says. "It's not loon armageddon - yet.
       A lot depends on where the mercury is coming from. If it's in
       natural bedrock and leaching through, that's one thing. If it's
       coming through the atmosphere then there's lots to do."
       
Excessive preeners
       Three years ago scientists discovered Keji loons have North
       America's highest recorded mercury levels. Now, in a report
       published in Conservation Ecology, Nocera and Taylor say loon
       chicks in Keji and New Brunswick's Lepreau watershed are engaging
       in excessive preening, and don't ride on their parents' backs so
       often.
       Riding on back protects the chicks from predators; excessive
       preening wastes valuable energy and so makes the young more
       vulnerable, too. Chicks with lower levels of mercury, a potent
       nerve poison, have not changed their behaviour.
       Coal-fired power plants, incinerators, and other industrial
       concerns puff mercury into the atmosphere. A recent report in
       Environmental Toxicology and Chemistry, Nocera said, showed the
       level of mercury in loon blood increases from west to east across
       the continent. Toxins are deposited in a similar pattern.
       Nova Scotia, Nocera said, is the tailpipe of North America.
       "We get all these atmospheric wind patterns that merge on Nova
       Scotia. When they cross Fundy they cool down, and precipitate
       here. That's why we get more precipitation than New Brunswick.
       "We can't point fingers, but all the evidence is pointing to a
       manmade source."
       Scientists studying pollution find loons especially interesting
       because loons are a top predator in the aquatic food chain, and
       absorb mercury from eating fish.
       This winter Nocera is finishing three years of graduate study. His
       last two summers were spent on the shores of Keji lakes, or lakes
       in the Lepreau watershed, watching loons from breakfast to
       sundown. Findings for New Brunswick are discouraging, too, but not
       as bad as Keji.
       A Connecticut native, Nocera came to Nova Scotia to work on loon
       research. The birds had fled Connecticut - and much of New England
       - before he grew up. He heard his first loon in Maine in the early
       '90s - and that was one crying from the ocean. He'd never seen a
       loon on freshwater before coming to Nova Scotia.
       The bird has three haunting, famous cries: the sad wail; the
       tremolo, a staccato that crescendos and then drops; and the yodel
       (made only by males). But in total, loons make five calls. "There
       are also the hoot and the mew," Nocera said, "very soft cat-like
       calls used only in family units. You have to be really close to
       hear them."
       
It's all in the air flow
       Loons cry by contracting muscles to push air through a
       complicated, multi-chambered windpipe.
       "We speak by contracting the larynx, which is like a knot, and
       controlling air flow through one channel. All birds have a syrinx
       instead of a larynx. It vibrates differently, and has four - a few
       birds even have eight - caverns inside it.
       "When they contract muscle, the syrinx vibrates in different
       patterns."
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References

   0. http://www.hfxnews.southam.ca/Perspective/Swick.html



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