an owl attack?

An extended and rather noisy attack by Blue Jays, Gray Catbirds and Tufted Titmice on a high, dense tangle of vines covering some old dead tree stumps suggested that there was an owl hiding inside but try as I might I could not find the apparent object of their fury. Could they have mistaken a knot or burl on the stump for an owl? Or were they perhaps attacking a spot where an owl had been seen in the past? Or was the owl so securely hidden inside as to be invisible from any angle?

Almost all the morning activity was again up at the head of the marsh with many 'off-plumaged' Goldfinches accompanied by a few other species: notably Baltimore Oriole, Ruby-throated Hummingbird and Common Yellowthroat. There was also a steady stream of Monarchs, a bit surprising at that rather cool early hour.

Peter Dorosh sent me the following link to a NBC news report on southern butterflies in Massachusetts:
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Two species are particularly noted, Giant Swallowtails and Fiery Skippers. This makes me wonder whether the skippers I saw yesterday (on the Rough-stemmed Goldenrod flowers along with the southern Red-banded Hairstreak) might not have been Fiery Skippers. I'll try to check it out again today.

Eric Salzman