This is very nice.
The diagonal lines created by the perch are very appealing. The bird's pose on the perch is also nice and follows that diagonal line.
The iridescence is very well shown.
The BG has a nice painterly feel to it.
The blacks in the wing tips and tail look like you may have done some PP there to get more detail and look a bit noisy.
Well done,
Gail
Neat image, I'm really digging that subtly streaked BG! Nice colours on the grackle...just wish for a tad better light quality, it seems like light was starting to get hard.