DDT may not have directly impacted bald eagles, but it has most definitely impacted their survival. The bald eagles often feed on rodents. If the rodents are dying early, the food source is scarcer, and bald eagles numbers suffer. Since eagles are carrion, they may even feed on the corpses of the poisoned rodents. Then that lethal dose of DDT is now in the eagle, and they die. I think the evidence is pretty conclusive.
It's well documented that the use of DDT pesticide killed many of the bald eagles in the areas that they sprayed, when DDT was no longer used then the bald eagle population started to grow again, I believe it's pretty clear that the use of DDT pesticides was the main cause of the decline in the bald eagle population.
I believe that pesticide use contributed to the decline of bald eagles. I did some research on the U.S. Fish and Wildlife Service's website claims that pesticides such as DDT causes their shells to thin and therefore break more easily. They point out that since DDT was banned bald eagle populations have soared. It is always important to consult multiple sources when doing research, and National Geographic seems to say the same thing.
I do not think that the use of DDT pesticide has contributed to the decline of eagles here in the United States of America. There is no proof to prove that there is a link to the two situations. I think that there needs to be more research done before such claims are made.