Mockingbird...but not...

[mr.sharp-photo]

i saw a bird in east york today. not sure what it was.
it looked like a mockingbird with slightly darker wings and a thinner, slightly-longer neck. it was on the ground looking for food for a while.
looked like a mockingbird without the roundness. more sleek....

[JW Mills]

Catbird perhaps?
Same size, but thinner, darker gray overall with a sliver of a black cap?
I say sliver because the guides say black cap and yet the ones I've seen had more of a sliver rather than a full cap.
 
http://identify.whatbird.com/obj/557/_/ ... tbird.aspx