While not a naturalist, I was interested by the link Instapundit provided to junkscience.com, which purports to prove that DDT had nothing to do with the decline of peregrin falcon populations. I checked it out: while the site does raise some questions (and forward possible alternative explanation) it seems to be a textbook example of someone picking and choosing their sources in order to support their position, instead of dealing with all the research present. I hadn't even been aware that the connection between DDT and thinning eggs was even in question (unlike, say, the question of whether DDT was carcinogenic). Frankly, It wouldn't be overly surprising if this were simply the usually assortment of anti-environmentalist contrarians, techno-fetishists and industry mouthpieces attacking the research, and I'm not about to dismiss what would appear as reliable science based on what appears to be highly dubious selection of sources.
Still, just as with the economists earlier, I'm always open to naturalists or scientists weighing in on this issue.