The Mystery of Zumbro Bottoms

Zumbro Bottoms is a whimsical name that seems more fitting for a circus clown who would have elicited laughter from my 10-year-old self.

It was around that age that my parents introduced me to this enchanting hilly landscape in southeastern Minnesota during a leaf peepers’ tour. Despite some development over the years, the area’s allure remains as the bending Zumbro River weaves its way through dense hardwood forest and past panoramic overlooks, ultimately pouring into the mighty Mississippi.

Those acquainted with Zumbro Bottoms may know it as a haven for horseback riders, boasting over 40 miles of equestrian trails and three designated horse campsites. The area primarily caters to horseback riding and mountain biking, so hikers should take heed of the designated trails and exercise caution. While delightfully beautiful, there are more suitable locations for a day hike.Zumbro Bottoms teems with wildlife, providing a sanctuary for raptors like the peregrine falcon and bald eagle. Fittingly, the National Eagle Center can be found in the nearby city of Wabasha.

The Mystery Begins

In 2016, a colleague and I ventured to Zumbro Bottoms and the nearby Kellogg WLA to capture some fall ambiance. At Kellogg, we recorded the sound of wind rustling through the tall grass prairie for a film project. Then, we proceeded to Zumbro Bottoms.It was there, along the grassy riverbank, that we exchanged puzzled glances upon hearing a low, fluttering rhythmic thump that occurred about every minute.

Thump-Thump Thump-Thump-Thump Thumpitty-Thumpitty-Thumpitty Thump.

We initially suspected our microphones were malfunctioning due to the day’s high humidity, which can cause “microphone motorboating.” My Sound Devices mixer had also just been repaired for a preamp issue. Bewildered, we eventually wrote off the mysterious noise with myriad explanations.However, this noise always sat funny with me. How could both our microphones experience the same problem simultaneously?

Fast Forward Years Later

I have heard the same enigmatic thump numerous times over the years, usually near water or wetlands, and always with the same rhythmic pattern. Despite equipment changes including microphones, recorders, and cables – the thumping would be heard. I would hear the sound even while simply out hiking. It clearly wasn’t the equipment, and it wasn’t my imagination.

What the heck was it? For Zumbro’s sake, I had to get to the bottom of it, and the truth would soon become clear. Thanks to extensive research and some enthusiastic members of Facebook nature recording groups, I uncovered the source which pointed me to Lang Elliott’s enlightening video.

The Mystery Solved

The puzzling sound was indeed none other than the drumming of a ruffed grouse. My colleague and I had unwittingly trespassed upon its territory.

If we were hunters, we might have known right away. Yet, since the frequency was so low and the timing so precise, it never occurred to us that it would be a grouse. It seems silly now as all the clues were there; we Hardy boys just failed to solve the mystery. However, the sound of grouse drumming will forever be etched in memory!

I regret not having the complete recordings to share with you from that fateful day. I must revisit my unedited recordings as I only have a short version with the grouse edited out. I was recording for a different purpose then and for shorter lengths. However a short sample can be heard by clicking the player. 

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During a more recent excursion to Zumbro Bottoms, I used a homemade binaural microphone fashioned with two DPA4060 mics, akin to the model sold by 3DIO. Regrettably, I was not impressed with the recordings, and the day’s soundscape didn’t prove noteworthy. It was an exercise in equipment, anyway. That’s a blog post for another day!

The Mystery of Zumbro Bottoms

Homemade Binaural Mic

I hope you found my mysterious adventure enjoyable and enlightening. It never ceases to amaze me how nature always has a few surprises up her sleeve.Enjoy the sounds of Zumbro Bottoms.All the best.

Picture of Jerry Horwath

Jerry Horwath

As a well-seasoned recording engineer who spends a lot of time in dark, windowless rooms, I truly enjoy being outdoors whenever possible. Nature and humor have always been my sources of comfort, so I decided to combine all three. That's how Wild Soundscapes came to be.