A site dedicated to the review and analysis of potential sasquatch vocalizations, Sasquatch Bioacoustic combines techniques from the domains of intelligence collection, audio analysis and bioacoustic studies to examine the evidence of sasquatch through their vocalizations. ~Monongahela

Sunday, February 24, 2013

Thoughts on the MN 2009 Howls Captured during a BFRO expedition by Andy P.

Originally posted on the BFRO's Blue Forum, the following is my October 14, 2009 response to AndrewP regarding the howls he captured during the BFRO 2009 Expedition in Minnesota:


There's so much going on in that first audio file that I wasn't able to get past it and on to the others this evening. But what I found in the file "MN09_01_09172009_Howlandwolves1" was well worth the effort.

I did some careful play back with good headphones and an audio analysis tool called "Sonic Visualizer". The software shows you a spectrogram of the audio as you're listening to it, and when visual cues are available, a lot more detail pops out of the recording.

I took screen grabs of the spectrogram and put them up at the links below. I edited notes into each image to indicate what I heard at each point in the audio file. Normally there's an easily visible "signal" just above or below the text I put on the image. But just to help, here's a little explanation of what I think each segment of the file contains (note, all of these images will look better if you click on the magnifying glass to enlarge the image).

Spectrogram 1 is from the first 6 seconds of the recording, and in it I can make out the loud howl of an unknown source, a quick bark-howl response, and the fading echo of the loud howl (an indication of the overall power behind the call):

In spectrogram 2 I can hear the wolf howl response to the howl(s) in the spectrogram above. The spectrogram also shows what appear to be harmonics of the wolf howl that run in sync, and at higher frequencies than the powerful base howl. But I think the interesting bit in this spectrogram is the second, faint ascending howl that appears at about second 10 of the original audio file. It's easy to overlook with all the loud howls in the foreground, but its there:

In spectrogram 3 I can make out two faint but noteworthy sounds. The first is a distant, descending call. It's too weak to discern if its a howl, but it has some of that characteristic. It also a lot like an owl, so that's what I tentatively label that call. The second sound is very difficult to see on the spectrogram, and almost impossible to note in the audio without a spectrogram. It's represented by a faint point of reddish color just below the "f" in the phrase "faint wood knock?". That's what it sounds like to me, not unlike the wood knocks I recorded in August of this year:

In spectrogram 4 we have a replay of the faint ascending howl noted in spectrogram 2 above. Sounds very similar to me, possibly the same animal. And competing with that howl, I can also hear the distant descending call from spectrogram 3, again. But this time its clearer, and doesn't sound much like an owl at all. It has more of a low, moaning howl quality to it in my opinion:

In spectrogram 5 we have a repeat of the first howl on this recording from the unkown animal. This howl is loud, clear and powerful. I used the term gutteral (sp?) to describe the quality of the howl, which seems so powerful it has qualities nearly approach that of a roar. This is a spectacular call:

And the final spectrogram, number 6, is the wolf howl response. Notice the harmonics reappear in this image, and note how level wolf's call is through out its duration. I've seen the same signature in several other wolf calls in these recordings (and others):

Hopefully ya'll find this interesting (I do anyway). And I'll be trying to do similar reviews of the rest of the recordings, time permitting.