Cornwall - Siblyback lake large bird in a tree (is it a cormorant?) (1 Viewer)

[Cornish mouse]

Hi I saw this bird high in a tree. It didn't look like the kind of bird you would find in a tree! This is the best picture I could get before it flew off, there was actually 3 of them in the tree that flew off together. It was by a large lake so I guess it could be a cormorant? What do you guys think.

 

[Alexander Stöhr]

Hello,

belayed welcome to Birdforum!

Yes, I agree with you: all birds in the pictures are Great Cormorants.
Ignoring vagrants, the shape is unique.
The sitting bird gave a slight Shag-vibe to me, but bill seems too long and inland location is bad for this?