is the absence of any mention of "Himalaya" blackberry (Rubus armenica, a.k.a. Armenian blackberry) in the understory of any of the six sites that he surveyed around Corvallis in 1952. For example, here's his description of the oak woodland area:
> The area covers about thirty-five acres and is dominated by garry oak > (Quercus garryana). There are many thickets of poison oak (Rhus > diversiloba) and wild rose (Rosa). At one end of the area are piles of > fire wood covered with poison oak, roses, and grasses.
At some of his other sites he mentions the native trailing blackberry (Rubus vitifolius), so he seems to have been paying attention.
This got me curious as to when Rubus armenica began to spread in the Willamette Valley. I found this in an OSU Extension circular:
"HB is a native of Western Europe that was introduced in the United States as a crop in the late 19th century. 'Burbank's Frankenstein' (after horticulturist Luther Burbank) is thought to have become naturalized in the West Coast around 1945."
So Himalaya blackberry was just beginning to spread in the wild when Richard Eddy did his field work.
Coincidentally or not, he also reported very few Common Yellowthroats -- none at four of the sites, and just 1 per 5 hours of effort at the oak woodland site.