LisaG what a great 1st Decorah visit you're having. What an eagle cam viewer blast
! Pip & I are grinning from ear to ear so hard our cheeks hurt.

Meeting Ambassador Decorah in person what a treat that must have been on
such a fine weather day at the Hatchery.

Safe travels back to MD.

The group was standing where the red X is on that 'elbow' of the Bike Path.
It was pretty hard to tell exactly which way the spotting scope was pointing & the peeps were looking.
The oblique aerial imagery in the image below was taken on April 19 2020.
I scanned the dickens out of all of the trees around there and I couldn't spot a nest (zoomed way in and from multiple angles).
https://beacon.schneidercorp.com/Application.aspx?AppID=110&LayerID=1180&PageTypeID=4&PageID=4263&KeyValue=112332800100
I believe N3 is somewhere inside the green ellipse on the other side of the Upper Iowa River from where they were standing.
That oxbow of U.I.R. looks like a nice place to fish. 
The back (east) wall of Walmart, which is parallel to the trail alongside the dog park, lines up with N3. Imagine a line extending across the river, and N3 is on the far bank. Because of the oxbow you can see why photos and videos have been a stretch.
iverburl - I tried to follow your description with my limited tools and talents. Is the attached in the neighborhood of N3?
Bingo.
Boy was I way off on where I thought N3 was from the BOTG field reports.
A slight disinformation campaign perhaps until after the ATF reveal
?

I thought for sure N3 was somewhere NW of Trout Run Rd & S of Iowa 9 somewhere in the BLUE ellipse just outside of the Trout Run WMA 'stair steps' of public land.
I had no idea Mom, DM2, 37, 38 & 39 were hanging out NW of Wally World snagging dropped parking lot corn dogs.

But seriously laying talons on all of the aquatic takings from just above the outside bank of that oxbow on the UIR and all of the surrounding fields for mammals is a brilliant sustenance strategy.
Unfortunately your present ice cream cone shaped nest is in a dead Ash tree ..
.. come on back to the Cottonwood fold.