Sunday, March 3, 2019

My Granary Tree, says the Woodpecker to the Squirrel

When a tree becomes ill, insects move in and start eating the tree. These insects are a major food for woodpeckers, indeed, they are the reason for the common name associated with this group of birds. They don't just eat insects, they also eat acorns. So do squirrels eat acorns. Hence the problem: how can woodpeckers store acorns so squirrels cannot get them?

The answer is something called a "Granary Tree". The bird finds a rotting section of tree, branch, or even exposed root, and pecks a hole into it just large enough to accept an acorn. Then, in the Fall, fill the holes with one acorn each, with the big, blunt, hard to grab end of the acorn facing out. Paws are not going to really help getting this slippery rounded thing out of a hole. Hence acorns stored like this tend to not be obtainable by squirrels. Woodpeckers just peck out the blunt end and eat the seed when they need it.

Here is one example from Rocklin, California earlier today:

That doesn't mean the granary trees don't get guarded... My son seems to have flushed a squirrel into a tree and in fact into a granary area, resulting in the squirrel hunkering down and enduring a dive-bombing and pecking by the woodpecker so calmly seen in the photo above. After a minute or two, I had to remove my son from the area to allow the squirrel to escape, as the woodpecker seemed to have attracted reinforcements that were joining the fracas.

Here is the woodpecker beginning to chase the squirrel:

Followed by squirrel hair collection activities by the same bird:

Food is serious business.

My son summarizes this much more succinctly: "The woodpecker is attacking the squirrel and then it is trying to knock the squirrel off the tree. And if the squirrel is knocked off the tree, maybe I can catch it [Editor/Dad's note - nope!]. And that is my blog post."

Saturday, March 2, 2019

How much Corona Discharge should be visible on PG&E (?) Transmission Lines?

Here is a neat trick to try on a moonless night - get a modern digital camera, a tripod, and a telephoto lens. Put the camera on the tripod, set the lens to a wide aperture (such as f/3 or whatever the lowest number happens to be for the lens you have), set the camera to its highest ISO setting, and take a 15 second or so exposure focused on the power line or the insulators supporting it on towers.

Look at the insulator - there are glowing purple blobs! This is on a 220-287 thousand volt transmission line near my home. I was trying to photograph the bioluminescence of Omphalotus mushrooms, but they appeared to not be in the mood, so I was looking for other things that might be interesting. I had seen a photo of power lines where the wires were all glowing purple, and thought that was what I would get from this method. Instead, it looks to me like the insulator is having a problem.

The purple blobs are ionized gas, in this case a form of plasma called "Corona Discharge". I cannot seem to find any information on how much should be visible on insulators, though what I have found would indicate that "very little" is expected on this type of insulating support.

Any time you are near high voltage wires and hear the crackling, buzzing sound typical of power lines, corona discharge is usually part of the sound generation. I never bothered looking to see where it was specifically being generated before, and was surprised that essentially the only stuff I could see was on the supporting insulators.

Corona discharge, in addition to eventually leading to the failure of insulators (hmm - I recall I live in PG&E territory - wonder if that's relevant), is the way power lines make ground level ozone and nitrogen oxides, neither of which are good for people.

It goes to show, keep your eyes open and you can see the unexpected in ordinary places!