Next up a few photos by--and of--one of the "3rd Gen" representatives:

This batch was taken by "G5" (grandchild #5 of seven) in 2017 at either  The Plains Conservation Center in Aurora, Colorado,  or the Rocky Mountain Arsenal NWR, north of the Denver-Aurora boundary.  

Plains is located almost literally in his  grandparents' backyard. (Disclaimer: It's actually a couple miles east of their house in Aurora.)  As a side note, his mother worked there in her "younger days."