Suicide Squad: Decoding All 16 Of Jared Leto's Joker Tattoos
Arms
13. The Dead Robin
Now, you might think that accepting that that bird on Joker's bicep is a robin takes some suspension of ornithological knowledge, since robins tend to be smaller, stout birds with proud red breasts. But that's English robins you're thinking of: the American cousin looks spot on for this tattoo (without the colour obviously) - they're taller, and more like a thrush. Thus concludes your lesson in birds.
Obviously there isn't much analysis of the imagery itself needed: it's another trophy image - like the J potentially representing Joker's murder of Jason Todd (and obviously his knowledge of his secret identity), the dead bird crows his defeat and murder of Robin.
For the Jason/Joker theroists, it might be a strange thing for Todd to have marked on his skin, but in tattoo symbolism, birds represent journeys and navigation, and a dead one refers to an individual having lost their way. It potentially still fits the theory.
12. Fore-Arm Smile
Again, it doesn't really take much to see that grim stretched smile is based on the Death Of The Family Joker skin mask smile, and more generally to Joker's traditional facial wounds that Leto's version does not sport.
On Leto's arms (rather than the toy representation of his character), the smile looks an awful lot like it's been taken from Alex Ross' iconic Joker design, given the shape and the thin upper lip. And the toothier look is definitely in homage to The Man Who Laughs film.
The best thing about the placement is that even when the Joker is defending himself, all you'll see is his grin.