Long-time evolution of a weakly perturbed wavetrain near the modulational instability threshold is examined within the framework of the compact Zakharov equation for unidirectional deep-water waves (Dyachenko & Zakharov (2011)). Multiple-scale solutions reveal that a perturbation to a slightly unstable uniform wavetrain of steepness µ slowly evolves according to a nonlinear Schrodinger equation. In particular, for small carrier wave steepness µ < µ 1 ≈ 0.27 the perturbation dynamics is of focusing type and the long-time behavior is characterized by the Fermi-Pasta-Ulam recurrence, the signature of breather interactions. However, the amplitude of breathers and their likelihood of occurrence tend to diminish as µ increases while the Benjamin-Feir index decreases and becomes nil at µ 1 . This indicates that homoclinic orbits persist only for small values of wave steepness µ ≪ µ 1 , in agreement with recent experimental and numerical observations of breathers.When the compact Zakharov equation is beyond its nominal range of validity, i.e. for µ > µ 1 , predictions seem to foreshadow a dynamical trend to wave breaking. In particular, the perturbation dynamics becomes of defocusing type, and nonlinearities tend to stabilize a linearly unstable wavetrain as the Fermi-Pasta-Ulam recurrence is suppressed. At µ = µ c ≈ 0.577, subharmonic perturbations restabilize and superharmonic instability appears, possibly indicating that wave dynamical behavior changes at large steepness, in qualitative agreement with the numerical simulations of Longuet-Higgins & Cokelet (1978) for steep waves. Indeed, for µ > µ c a multiple-scale perturbation analysis reveals that a weak narrowband perturbation to a uniform wavetrain evolves in accord with a modified Korteweg-de Vries/Camassa-Holm type equation, again implying a possible mechanism conducive to wave breaking.