[Tweeters] Dipper Behavior Surprise

[normandlaura donelson via Tweeters]

Yesterday I birded the Oxbow Loop Trail, off Middle Fork Snoqualmie River Road east of North Bend.  New trail for me, and I highly recommend it!

I took the spur trail down to the riverside, and soon spotted a pair of Dippers.  They landed on a large rock at midstream, then on a smaller nearby rock.  There was some fluttering, then I saw the pair of them floating downstream, one atop the other!  There was still much fluttering from the upper bird, as it tried to hold its position.  This only lasted for a few seconds.

I can only think they were copulating.  Have any of you seen this behavior, or heard of it before?  The closest I got in a quick online search of the literature was a mention of an observation in which copulation occurred while the female was standing submerged in the water.  If this floating copulation behavior has been seen before (and realistically, I have to suppose it has), I couldn't find evidence of it.

I should also note the alternative possibility that it could have been two males in Dipper combat, though nothing about the incident struck me that way.

Interested in any observations you may have,

Norm Donelson
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