Interesting. I hadn't seen this video or videos like this before, but it does make sense that this could be caused by the transformers. Though I haven't personally heard them make this noise.
I heard them when I was a kid waiting for the bus on cold winter mornings in rural Indiana. There were them tall wooden pole electrical lines with thick cables with a transformer on one of them the next house over. If the wires weren't singing, the transformer was humming. Taxing my memory, I recall both happening at the same time.
Unless the conditions are just right, I don't if one would hear such noises in the middle of the woods at least a mile away from any power lines or major power sources.
