I just got reminded about why it's better to go directly to the source than to rely on secondhand information. I was able to find the original blurb about the organic farm study in the July/Aug 2006 Audubon magazine online.
In reading it, I realized that the story was misquoted somewhat in Utne. (I am disappointed in Utne. I thought they had better journalistic standards than that.) As summarized in Audubon, the original study was a four year study, not a five year study. And while the percentage increases were correctly reported in Utne for plant species and number of bats (105% and 75% respectively), the percentage increase for winter birds was 62%, and there was actually a 48% increase in spiders. Insect species and/or numbers were still not mentioned.
My junior English teacher in high school had us do a great exercise comparing the same story as reported by several different sources. I have never forgotten how different the story was depending on who reported it.
And it makes me wonder what changes have occurred in the translation between original study and the report in Audubon.
Anyway, despite the discrepancies, the message remains the same.
Now I'm on a quest to find the original study report.