Hello Paul.
The practice of storks nesting on electricity pylons is not new. Although the Spanish love the storks not every one wants to have them nesting on their roof.

I cannot speak for Extremadura but in Cadiz, Sevilla and Huelva provinces most electricity pylons are equiped with metal spikes at the top to encourage storks to nest there. The spikes are used to anchor the sticks and twigs that the storks use as nesting materials and gives the nest a firm support against high winds.

Another system that is in use is to fit platforms to the top of pylons but as these are flat they do not give as much support.

Alongside the Algeciras - Ronda railway line near to Los Barrios (Cadiz) you can travel for a few kilometres and see stork nests on every pylon. Beside the railway line that runs beside the Rio Tinto in Huelva there is the same effect.

In a wonderful birding area in the Donana region, Dehesa de Abajo, there is what is considered to be the largest nesting stork colony in Europe. These birds (which number thousands) only nest in trees.

In my own little village, Villamanrique de la Condesa, we are lucky, as the birds maintain tradition and nest on the church tower. We had four nesting pairs this spring which produced ten chicks.

Regards and best wishes.

John Butler.

Donana Bird Tours.

Hello Paul:
The using of pylons as nesting sites for White Storks is deeply related with the increasing of the population and the saturation of the traditional nesting places. The White Stork population in Spain, in 1984 was about 6.753 pairs, in 1990 7.821 pairs and in 1995 16.643 pairs (a larger population than in the 40's). Increasing has been motivated by the discovering of new feeding sources (mainly rubbish dumps), but the new pairs do not colonize the same habitats due to a population saturation level. As John Butler says, some of the electricity pylons has rounded metal platforms to encourage new nesting placements, but this is only made in areas where the specie is wanted to increase or settle. Most of the metal spikes at the top of electricity pylons are there as a correcting way to avoid electrocution when the birds perch on. The Regional Goverment of Andalucía, and in Extremadura too (close or in the protected reserves)force to the Power Companies to erect poles with those spikes. So, can be say yes to your question, having in mind these facts.
Hope this helps,

Regards from Doñana

Jorge Garzón
Investnatura-South Birds
"Nature & Birdwatching"