  We consider the description of form factors of local and Wilson line
operators (reggeon amplitudes) in N=4 SYM within the framework of four
dimensional ambitwistor string theory. We present the explicit expressions for
string composite operators corresponding to stress-tensor operator
supermultiplet and Wilson line operator insertion. It is shown, that
corresponding tree-level string correlation functions correctly reproduce
previously obtained Grassmannian integral representations. As by product we
derive four dimensional tree-level scattering equations representations for the
mentioned form factors and formulate a simple gluing procedure used to relate
operator form factors with on-shell amplitudes.
