The Bitterroot Valley of Montana has been the site of a large number of wildlife malformations and declines since 1995. These have included moose, elk, bighorn sheep, white tailed deer, birds, and rodents. A study of genital malformations conducted from 1996 to 2000 showed that as many as 67% of male deer studied had genital malformations. These abnormalities included “varying degrees of apparent genital developmental anomalies, specifically mispositioned and undersized scrota and ectopic testes” Because several pesticides have been shown to induce these kinds of malformations, like malformations at the Hanford site in Washington, and Malhuer National wildlife refuge in Oregon, pesticides were looked at as a possible cause. In 2008 a risk assessment of the Bitterroot Valley was conducted and pesticides were found to be present in the environment, including pesticides like Chlorothalonil that are not used in the Valley but are carried over the Bitterroot mountains from potato fields in Idaho. This demonstrates that these chemicals can travel long distances from their sources.

Judy’s current documentation of genital malformations reaches beyond just white tail deer in the Bitterroot Valley, and includes Yellowstone, and Glacier National park, and affects Mule deer, bighorn sheep, moose, elk and bison as well.

Besides conducting the white tail deer study back in 1996, Judy has been documenting other wildlife malformations and their causes ever since. Much of the source information on specific malformations on this site come from Judy’s work, including the vast majority of the information here.

Besides genital malformations, Judy has also documented wide scale occurrences of under bites and other malformations. Many of these have been recently documented in mule deer and antelope in Utah as well. Judy found malocclusions in a Nevada antelope back in the 1990s, and a couple of mule deer in Utah as well.

Unlike Rocky Mountain elk across most of the West, Bitterroot elk have declined like Lolo zone elk in Idaho for the last 20 years. And in the same pattern as bighorn sheep in Thompson falls, MT. Herbicides are used on timber harvests in the Bitterroot Valley. One of the herbicides used, Aminopyralid was first introduced in 2005, and is very persistent in the environment. The manure of animals that have eaten Aminopyralid treated vegetation with kill plants that it comes in contact with, and remains active for up to year. So not only are wildlife potentially harmed by this product, they help move it through the ecosystem as well.

Aminopyralid is in the Picolinic acid family of herbicides. “Picolinic acid acts as a chelating agent of elements such as chromium, zinc, manganese, copper, iron, and molybdenum in the human body” Aminopyralid is chemically very similar to Picloram the only difference being a single chlorine molecule. They both work by the same mode of action. Picloram is known to damage the endocrine system.

The North end of the Bitterroot valley is within the Lolo National Forest. In the early 1980s herbicide use ceased in the Lolo National forest for weed control. In 1992 it was brought back, and expanded. This includes the aerial spraying of Picloram, 2,4-D, and Clopyralid.  2,4-D is a known endocrine disruptor.