Reader Question: Mystery Creature's Night Sounds

I recently received a question about a mystery creature in the comment section of one of the earlier posts on this blog and I wanted to share it and my reply with everyone:

Question:
"I hear a sound out of my 200 year old oak tree at night that sounds like clipping scissors. am suspecting it to be a squirrel. It's very sharp and keeps me up at night? am I right? What else could it be?"

Answer:
Some squirrels do indeed make a short, sharp high-pitched noise which is often regular in frequency for an extended period, perhaps every second or two. Most squirrels, however, are diurnal, sleeping at night. The exception is the flying squirrel (Glaucomy sabrinus or Glaucomy volans). Depending upon where you live, this might be the best possibility, although I don't know from first-hand experience what a flying squirrel sounds like. There are some birds and many insects that call at night as well, and these can't be entirely ruled out without more information. Try this experiment: place an 18" square piece of anything that's very flat and smooth (and preferably dark colored) out near the tree from which the sound originates. Sprinkle a light coating of talcum or other very fine powder evenly over the flat surface and placed a few peanuts, some peanut butter, or a crust of bread in the center of the board. In the morning, look for foot-prints in the talc. Flying squirrel feet would have tiny but well-defined finger-like toes. The front feet will leave prints almost like tiny hands and the rear feet will have pads that are a bit longer. Both prints may show evidence of the pointed claws they use for climbing. Use an online or printed animal footprint guide to compare against other small rodents which might be active at night.

You can also use an automatic trail cam to snap a picture of anything that comes to take the "bait" instead of using the tracking powder. If you place the baited platform several feet off the ground under the tree, you may also see evidence of the flying squirrel "landing" after leaping from above, providing even more evidence.