Crows are serious—and seriously creepy—wherever they show up. In most of their fictional appearances, they are the go-to scary bird, and are traditionally associated with death in many mythologies and cultures.
On the other hand, crows are also very clever. They may feature a crow as:
the "Deadpan Snarker" - A character given to gnomic, sarcastic, sometimes bitter, occasionally whimsical asides.
The Deadpan Snarker exists to deflate pomposity, point out the
unlikelihood of certain plans, and deliver funny lines. Typically
the most cynical supporting character. In most cases, it is
implied that the snarker would make a good leader, strategist, or
consultant given their ability to instantly see the flaws in a
constructed plan;
the "Trickster Mentor" A Trickster whose actions, while seemingly
pointless, selfish, antagonistic, or just plain random that contains a valuable lesson.
In more fantastic settings, a Trickster Mentor educates their proteges by subjecting them to various transformations, body-swaps, literal wishes, and faked tests of
character. Trickster Mentors love it when someone who first meets
them doesn't realize who they are. They get to assess the "true
character" of someone, then beat their sense of superiority out of
them with it after the revelation. Or, rarely, give them a small
break if they reveal honesty and good intentions.
or the "Zen Survivor" A character who has been through utter hell,
and came out sad, cynical, and wise beyond their years. Part of their
wisdom is knowing that it is wasted on most people, so they don't go
around babbling it to everybody. Instead, they wait until they see
somebody who is worthy, and serve as the worthy one's mentor.
As for Uchiha Itachi, his summoning technique best suited for what happened in his life. Itachi with his symbolic crow can be related to the "Zen Survivor" of his clansmen who is wise beyond their years (technically because of his age) and serves as a worthy one's mentor (both Sasuke and Naruto). On the other hand, the "Trickster Mentor" part also include faked tests of character also for both Naruto and Sasuke.
Please comment if you want to clarify something.