Yes, the early hypothesis as to *how* DDT caused bird mortality was wrong. It is not unusual in science for a hypothesis put forth to explain observed data to be wrong. But the base of the hypothesis - that the correlation of bird mortality with the introduction and rapid rise in usage of DDT was too strong to be coincidence alone - has since been proven correct.
Beyond doubt. This is a non-issue in science.
Here's the quote from Crichton's essay:
"I can tell you that DDT is not a carcinogen and did not cause birds to die and should never have been banned. I can tell you that the people who banned it knew that it wasn't carcinogenic and banned it anyway".
The entire essay doesn't contain a single original thought, I hope you're smart enough to see that. Each of the arguments he presents is part of the standard sermon preached by those who would have us ignore science unless science tells us we can do whatever we want without doing any environmental harm whatsoever.
Tch tch. His science fiction's formulaic and free of originality as well.