When you think of Glacier and potholes, you probably think about the ones on the way to Polebridge Mercantile or Many Glacier.
Have you ever heard of a prairie pothole?
Far northern Montana, including parts of Glacier National Park, is part of something called the Prairie Pothole Region. This region is a type of landscape in the Northern Great Plains dotted with sunken wetlands. From above, they look like potholes filled with rain.
Like kettle lakes, prairie potholes formed with the retreat of glaciers. As these hulks of ice and sediment heaved across the ground, they scarred the earth, leaving millions of little depressions. Today, those dips fill with water, creating wetlands that can be temporary or semi-permanent.
So, what happens in and around a prairie pothole, and why do we care? Astonishingly, the Prairie Pothole Region (PPR) is breeding habitat for up to 75% of all North American waterfowl. This includes species found in Glacier like Barrow’s Goldeneye, Redhead ducks, and Trumpeter swans. These birds, along with a wide range of shore and grassland birds, benefit from abundant prairie pothole lakes found just east of the park.
Potholes are crucial for breeding because they provide the right type of food and shelter needed for nesting and raising young. Aquatic bugs and plant seeds fatten up nesting hens preparing to have babies. Their mates enjoy these food sources, too, and defend the females in turn.
About 50% of wetlands in the PPR are gone. They get drained and filled for agricultural use, reducing waterfowl habitat. The success of these breeding habitats relies on precipitation and temperature, too. Wet years mean booming waterfowl populations; dry years cause droughts and populations decline. As temperatures rise, wetlands will need a corresponding increase in precipitation to survive.
Have you seen any prairie potholes in Montana? Did you notice any interesting birds while you were there?
[Image 1: Black and white duck with black head and bright yellow eye. Image 2: Aerial view of green landscape dotted with many shallow ponds. Image 3: Silhouette of duck taking off from a lake at sunset.]
