"Night is drawing in" can mean so many things. It can be that the days are getting shorter or it can have a more personal note as drawing someone into a conversation, for example.
In this instance, this might have been one of the last opportunities I have of photographing an adult Black-Crowned Night Heron prior to its migration south from the Calgary area.
This, I believe, is one of a pair who actually nested and produced one offspring, which probably explains so much activity in the late Spring. (See Blog "The Night is Still Young - July 20, 2023.) One can only hope that they return next year to repeat the same chain of events.