Cat-proof Birdbath

In this Instructable we will make a birdbath that (hopefully) will be immune to unwelcome feline attention. To do this we will use:
1 tree
2 London taxi-style hubcaps, as found on the verge
1 bolt
1 washer
1 tube of silicone
Assorted standard tools

Well, not exactly 'cut down', but it certainly won't be buying you a drink next time you meet.
Essentially we're looking for a tall post that will prevent cat-pouncing, well anchored to the ground. Sounds like the first 10' of a birch tree... We had a suitable candidate, a beautiful tree, but sadly its root system was starting to destroy our pathway.

We need something vaguely horizontal, otherwise the water'll fall out, so trim the tree to give a nice, neat, horizontal post.

Now we need to drill a hole so that the bird bath can be securely fixed in place. Might as well drill a hole in one of the taxi hubcaps at the same time...

This hubcap is the connection to the tree, it has a hole in it (so far), now let's cut it down to a frisbee-esque disc that'll form a good base for the other hubcap (oh yes, you'll need two)...

You can't have a dirty birdbath: the wee sweeties'll sicken. So wash those hubcaps.

Purely a cosmetic detail, but let's make it nice.

Base, bolt & washer ready to fix to the tree

Now bolt the base to the tree

The base gets siliconed generously, so as to adhere securely to the second hubcap

Press the second hubcap onto the remains of the first.
Use a spirit level to try and get it reasonably horizontal.

Know locally as the devil

Ok, it's a bit silver

It's time to fill the birdbath with water.

It's a few months since the installion of the birdbath, it's been quite popular with the birds.
The main problem with it is cleaning & refilling it, which I need to do atop a set of steps.
The tree has regrown a surprising amount