Poop For a Purpose: Estimating Mountain Goat Populations

Jordan Lefler

When you think of science, what do you picture? Maybe you see a laboratory and tiny particles moving under a microscope, or maybe you imagine test tubes and beakers filled with colorful chemicals. But do you ever picture climbing mountains or hiking deep into the wilderness? When you think of a scientist do you see safety goggles and a white lab coat? Or hiking boots and a field guide? 

For Glacier’s Natural Resources Program Manager Mark Biel, and the other scientists in Glacier National Park, science is a living breathing thing that takes shape across the park’s vast landscape. And for Biel, that shape is often white and fluffy with cloven feet and horns.

Estimating goat populations

Since coming to Glacier in 2010, Biel has been involved in multiple studies surrounding the park’s iconic mountain goats. The most recent of these studies aims to create a robust estimate of mountain goat population size and density across Glacier and Waterton Lakes National Parks.

“The goal of this goat genetics project is to come up with a minimum population estimate for the mountain goats in the park that will help us make better informed management decisions,” Biel explains. “Essentially, it’s hard to manage something when you don’t fully understand where you’re at.”

Until now, the park has been relying on broad estimates of the goat population, but wider estimates result in a larger margin of error. So they set out to find a way to more precisely assess the number of mountain goats in Glacier National Park. The answer? Goat poop.

Goats in the park, Joey Wang

Extracting DNA

“We came up with the idea of using goat pellets and extracting DNA from them,” Biel says. “From that we can get down to individual goats.” 

In 2022, USGS and NPS Technicians worked with citizen scientists to collect fecal pellet samples from across Glacier and Waterton National Parks. They developed a grid system that divided the parks into distinct regions for sample collection. Some of these regions were accessible by seasonal technicians, while others required specialized volunteers with experience tackling rigorous terrain. 

“Between our seasonal technicians and volunteers we got close to a thousand samples,” Biel says.

A number of these samples were sent to a lab at Oregon State University. Using the DNA left in skin cells found in the pellets, the lab could extract complete genotypes for the goats. This tells the team how many individual goats the samples came from, and allows them to determine whether the goats are in one large population across the park, or smaller more isolated populations in different regions. It also helps them identify which goats were where, and when, along with different genetic factors of the individuals. All of this information helps to improve the accuracy of the population estimates.

Moving forward

Now, with the help of Glacier National Park Conservancy funding, they’re sending the remaining samples to the lab to expand the data set they’re working with. With this new round of data, the team is hoping to build a baseline genetic database. This will help them evaluate the movement of the goats across developed areas such as roads and trails, and analyze how habitat and stressors can impact population density. 

“Doing what we’re doing with this study will allow us to be better managers and observers,” Biel explains. “It’s really strong science that we can base management decisions off of.” 

Ultimately, the work being done in this study will give park managers the information they need to ensure Glacier’s mountain goats remain a key part of this incredible place for generations to come.