Documntrs is the oddest abbreviation of Documentaries I think I've ever seen.
Considering the folding ident/logo, they are missing a trick by just labelling it as Sky Docs as that is what viewers will see in the ident before it fully reveals itself.
Are Sky Nature and Sky Documentaries both broadcasting in 2160p?
Wasn't the announcement that their 2160p content would be available on-demand?
I don't think there was a suggestion that they would run SD, HD and UHD broadcast channels (or use their small number of UHD ad-hoc streams to overlay the HD channel with UHD content when the source was UHD - as per Sky Sports UHD?)
Checking on kingofsat there are only SD and HD channels listed on 28.2E for Sky Nature?