I had an interesting conversation at dinner at a friend's house on Saturday. It led me to write John Blakeman who, as ever, promptly responded. Here 's the correspondence:
At dinner last night someone who seemed rather knowledgable was speculating about the Pale Male nest failure, and my idea that the new "cradle" is likely to have been a cause. He introduced an idea new to me: that the steel structure, combined with other metal materials that might be in parts of the cradle--screws, bolts, etc., would combine to become some sort of battery -- and create electromagnetic effects of some sort. It sounds far out, and I'm probably not presenting the guy's idea accurately. Indeed. I didn't understand it much at the time. But I wondered if this might stimulate any ideas.
The fellow who proposed the "metal effects" remembers his college chemistry or engineering classes. There is no doubt that corrosive chemical reactions involving the "mutes," the falconry name for hawk droppings, would be electrochemical in the new nest structure, which was constructed of at least two different metals (which is required for corrosive electrochemical reactions). As the person knows, it is crucial that the two different metals be in direct contact with each other and that they must be wetted. Such reactions are said to be "galvanic," and yes, they will produce small electrical currents through the metals.
But I seriously doubt that these charges would have been sufficient to cause any egg abnormalities. The current flow would have been in microvolts, and it would have grounded out to the building to which the structure was attached, I believe. I can't see how there could have been a current flowing through an egg, even if it were touching one of the metal prongs.
If galvanic reactions between two metals and the mutes were serious, the one of the metals will be slowly sacrificed in the corrosion. Something will fall off someday. The structure will corrode, the same thing that happened to the Statue of Liberty, causing it to be rebuilt a number of years ago. There, instead of hawk mutes, the offending liquid was salt spray that caused galvanic reactions between the copper cladding of the statue and the interior iron support skeleton. But that took over a century to be significant.
For the Pale Male nest, good thinking, however. Something else, perhaps just as anomalous, was at fault.