Farms can be toxic for birds
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Farms can be toxic for birds
Date:
Fri, 30 Aug 2002
From:
Stephen Tvedten <steve@getipm.com>
Organization: Get Set Inc. (www.getipm.com)
To: Paul Helliker <phelliker@cdpr.ca.gov>
Director, State of California, Department of Pesticide
Regulation
cc: Christine Whitman whitman.christine@epa.gov
At website for Environment Canada Pacific and Yukon Region http://www.taiga.net/yourYukon/col196.html
Column# 196 Farms can be toxic for birds. Migratory birds live a pretty healthy life while they are here in the Yukon. They have to watch out for natural hazards such as predators, but at least exposure to pesticides is not a major problem while the birds are north of 60.
But when they head south for the winter, it is a different story altogether, particularly if the birds spend time in agricultural areas.
The synthetic chemicals used to control pests kill huge numbers of birds every year, and the death rate is high in North America as well as in developing countries.
Countries in the developing world often receive most of the blame for this on-going problem because they still use chemicals such as DDT and monocrotophos that have been banned in North America.
But Pierre Mineau, a research scientist with the Canadian Wildlife Service, says that both Canada and the United States are far from blameless on the pesticide front. During his 22 years of work as a wildlife toxicologist, he has fought long and hard for bans on chemicals used in North America.
"We are certainly killing our share of songbirds here as well," he says.
The issue of grasshopper control illustrates his point. Farmers in Argentina used monocrotophos to kill grasshoppers until it was learned that this organophosphate pesticide was killing thousands of Swainson's Hawks feeding on the insects.
In Canada, the pesticide of choice for killing insects such as grasshoppers was carbofuran, which is twice as toxic as monocrotophos.
The liquid form of the pesticide was finally banned here for grasshopper control, but it can still be used in corn and potato fields. The granular form of carbofuran was still used up until 1998, and it was particularly deadly for birds as they picked it off of the surface of the fields.
Granular carbofuran is still used in the United States for a few crops although its use has been severely cut back from what it once was. More worrisome are extensive use patterns in most of Central and South America. Mineau says that even though there is plenty of evidence that carbofuran is bad for birds, it is still hard to get restrictions placed on its use. Part of the problem is that dead birds are hard to find.
For example, researchers conducted a number of small-scale but intensive searches for dead birds in US cornfields treated with granular carbofurans. Based on this sample, it is estimated that this pesticide killed eight million birds per year in Midwestern cornfields before this use was cancelled.
But - unlike the Swainson's Hawk case - there is no huge pile of dead songbirds that can be used to illustrate the problem. In fact, in the vast cornfields of the Midwest, dead songbirds can be extremely hard to find, and only a few dead birds are reported to government agencies every year.
Mineau does not think that we should wait until more carcasses are collected. "How many dead birds is enough before we start to worry about our use of granular carbofuran?" he says. "Why tolerate eight million songbirds being killed in US cornfields if there is another alternative?"
For Mineau, this is a solvable problem. It is just a matter of using the right pesticide for the job. He says that it is possible to make more selective pesticides, the only problem is that they are more expensive to make than the chemicals that kill a wide range of pests.
"The ideal pesticide takes out the pest and nothing else," he explains.
Mineau compares pesticides to medical drugs. "They are like antibiotics.
They have saved a lot of people but they are seriously overused.""
For signs of success, he points to Great Britain, where chemicals shown to kill birds are quickly taken off of the market, and to Europe, where no-spray zones are left around the fields.
Mineau points out that pesticides - even strong ones - do have their place. "Not all pesticides are bad. The point I'm trying to make is that some of these products have been with us since the 1940s, and it is time to get rid of them."
Since agriculture is not a big industry in the Yukon, not many pesticides are used in the territory today. The health of Yukon birds is particularly dependent on what happens in other parts of the world.
Even though peregrines have recovered since DDT was banned in North America, the chemical is still used in countries where the birds spend their winters. Also, birds that peregrines eat could be getting heavy doses of pesticides.
After 22 years working as a toxicologist, Mineau still has hope that pesticide problems can be solved. "I happen to think that in many cases this is an easy one to solve as there are alternatives," he says.
Pierre Mineau is the head of the Pesticide Section of the National Wildlife Research Centre with the Canadian Wildlife Service. He can be contacted at Pierre.Mineau@ec.gc.ca.
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More on monocrotophos, a highly dangerous organophosphorous cholinesterase inhibiting insecticide which was used as a bird poison and is highly toxic to mammals at http://www.ace.ace.orst.edu/info/extoxnet/pips/monocrot.htm
Rachel Carson, noted in Silent Spring, 1962: "We should no longer accept the counsel of those who tell us that we must fill our world with poisonous chemicals; we should look about and see what other course is open to us."
I have posted a free pest control book on the web that uses safe and far more effective alternatives, it is entitled: THE BUG STOPS HERE. You can download it for free at: http://www.thebestcontrol.com .
Respectfully, Stephen L. TvedtenIf you would like to be included in our mailing list for continuing information on pesticides, please email us at list@safe2use.com.