Doing a quick bit of Googling it does look like these high temperature power lines do exist to a limited extent in Germany. This news story (date not given, but must be 2012 at the earliest) from RWE's website talks about the first ever high temperature power line, of about 12km length, to be installed in Germany:
The operating temperature is given as 175ºC rather than 210ºC.
With normal temperature power lines birds have no trouble, as far as I'm aware,in perching on them and may even be attracted by the warmth. It would be interesting to see the reaction of the German green movement if birds tend to get injured in trying to perch on these power lines that are operating at oven-like temperatures.