Digital Sunset

My divorced parents are going on a cruise, together, over what used to be their anniversary (don’t get me started) so I am bird sitting for my mother.  Admiral Johnny Depp is my mother’s 9 year old cockatoo and I was told to put him to bed each night at six by putting a sheet over his cage.  Today, I didn’t get home until seven and he was squawking and carrying on in the darkened house.  I threw the sheet over his cage so it went from dark to a slightly different dark and he seemed to calm down considerably.  I wonder if there’s a state where I would ever be disquieted by an analog sunset.