You don't suppose the rest of the trees were affected by the soot of the coal age do you? And yes, birds for which the camo would matter, are not the only predator that east moths, but they do eat them.
Possibly. The moths roost on the underside of small branches among the leaves of the trees. Its unclear that their coloration had a significant effect on their chances for survival. The experiment was supposed to show that birds were able to see the lighter moths easier and were eating them at a greater rate. This was supposed the be the cause of the increase in darker colored moths. The problem is that the experiment placed the moths in unnatural positions on tree trunks where they were exposed to the birds. The experiment was flawed and should not be used as an example of natural selection.