High risk poles have certain features which can make them lethal to birds.
They are basically badly designed / constructed, with no thought for wildlife:
Photo by Amartuvshin Purevdorj, 27 August 2010
Electrocuted Upland Buzzard, Uulbayan, Suhbaatar province, Mongolia.
Photo by Elfin Lewis
This is the medium voltage power pole which electrocuted Jimmy
which has 6 out of the 8 'Killer Pole' features listed above.
Solutions to killer poles and other mitigating actions can be read about here.