The town of Silvercreek has seen a steady decline in the population of its native songbird species over the last decade. Local environmentalists attribute this decline primarily to the increasing use of a new, highly effective pesticide, "PestGone," by residential gardeners. PestGone targets insects that are a primary food source for these songbirds. Therefore, to reverse the decline in the songbird population, the town council is proposing a ban on the sale and use of PestGone within town limits.
Which of the following, if true, would most weaken the argument that the proposed ban on PestGone will reverse the decline in the songbird population?