This is a humorous look at the idea of whether or not something is truly what it seems. It explores the idea of perception and how we can be fooled into believing something is something it is not. It is a lighthearted look at how we can be deceived and how we can be wrong
From Wikipedia
Is this a pigeon? is an Internet meme and quote of the protagonist from the 1990s Japanese anime television series The Brave Fighter of Sun Fighbird. The image originates from a scene where the character mistakenly identifies a butterfly as a pigeon. The image was originally posted on Tumblr.