Report 65464: Vocalizations near the summit of Silver Star Mountain

My girlfriend and I both had Friday off, 5/15/20, and decided to go do one of our favorite hikes up to Silver Star Mountain in Skamania County, Washington. We live in Portland and go up to that hike at least once or twice a year. We regard it as one of our favorite hikes in the area due to its proximity to home and its sheer beauty. I was born in rural SW Missouri, and then spent my formative years growing up in Colorado. I am an avid outdoorsman and spend a large amount of time backpacking, hiking, camping, snowboarding and surfing in the wilderness (as well as my girlfriend). I went to school for/work in environmental science and have years of experience collecting data in nature, including animal tracking and navigation. We left around noon and arrived at the Grouse Vista Trailhead and began our hike at 1PM. The hike is around 6.8 miles roundtrip and can be challenging on the way up due to the 2,000 feet of elevation gain to the top of Silver Star Mountain. The trailhead was filled with cars, although most of the foot traffic we encountered was on the way up as others were headed down. We like to hike in the afternoon for this very reason. We are both active/fit and didn’t stop on the way up except for once when nature called. Near the top, we encountered some snow (as was expected), but not nearly as much as the year prior. We finished the hike and were at the top of Silver Star Mountain. It was overcast with patches of sunlight, but no wind or rain and was generally pleasant. During that time, we were alone on the craggy peak and only a handful of other people were on the ridge to the south. The mountain is surrounded by valleys carving through the landscape on all sides. My girlfriend is in the medical field as was on call that day. She was digging through her backpack for her work phone to check voicemails (we had very limited service). I was rummaging through my pack for snacks. It was during this time that I heard the first series of very strange noises from the closest valley to the north. It was a distinct and loud “whoooo-ooop whooo-ooop”. The first “whoooo” segment of the noise was deep, with second “ooop” part having an extreme pitch change that I could not correlate to a known animal. I ask my girlfriend if she heard it, but she was preoccupied with her phone. It was around this time that a couple of other hikers showed up with their dog. We wanted to sit out on the rocks overlooking the views, so we moved slightly further down the ridge from them to a rock outcrop and ate some snacks and took photos (I can provide these photos for reference). In between conversation, the noise happened again from the same spot in the valley to the north. It was about 15 minutes from the first one. It was loud and filled the entire valley, giving me the feeling that it was a rather large animal. My girlfriend heard it this time and we both looked at each other puzzled. The other hikers behind us were carrying on conversation and didn’t seem to be paying attention to the noise, but their dog had kept going to the ridge and looking to the direction of the noise. We waited in silence to hear it again, but never did. We decided to head back down the trail. About halfway back down, the trail passes beneath Pyramid Rock. We had always wanted to scramble this rock to see the views and felt energized that day to do so. Pyramid Rock is comprised of loose talus and can be dangerous to climb. We picked our line going up the north side of the rock, which was rather steep, and came to a shallow cave toward the top. It was probably 20 feet wide and 20 feet high, but maybe only 10 feet deep. There were remnants of a campfire here, as well as a 4-foot wall or blind made of stacked rock around the entrance. After making it to the top, we decided we were hungry so we high-tailed it back home. Upon returning home, I decided to check BFRO for reports from Silver Star Mountain and found Reports #13115, #1652. These reports are from the exact area we were in. The photos included in Report #13115 were taken from the top of Silver Star Mountain where we were sitting and heard the noises. I would also like to note that the first few seconds of the Berry-Morehead “Whoops and Knocks” audio here on BFRO are nearly identical to what we heard that day.