Weed Control has Caused Skylark's Decline (Letter to the Editor)
From Mr Gregory Conko.
Sir, Your article "Bird numbers `under threat' from GM crops" (September 1) reported on a study in the current issue of the journal Science, which suggests that genetically modified herbicide-tolerant crop plants could have a significant negative impact on wild bird populations in the UK.
The Science study relies on a highly theoretical mathematical model to estimate the reduction of weeds (the seeds of which are the primary food source for skylarks) and, only secondarily, to estimate an effect on bird populations. Fewer weeds in fields planted with GM herbicide-tolerant crops, it is estimated, would also mean fewer birds.
This tactic, however, unnecessarily confuses the effects of genetic modification with those of common agricultural practices. Farmers will make every economically efficient effort to eliminate weeds from their field — whether they grow GM plants or conventionally bred plants — because weeds compete with the crops themselves for soil nutrients, sunlight, and water. Efficient weed management is probably the single biggest reason why skylark populations have fallen by half over the last 30 years, well before the introduction of GM crops.
Before the study was even published, it had been roundly criticised within the scientific community for this unrealistic comparison. A number of independent scientific critics could have credibly commented on the questionable relevance of this report.
A more comprehensive treatment of the relevant issues would better serve your readers.