Low-density nuclear matter at finite temperature is considered representing the strong coupling situation of a highly correlated fermion system. One-particle self-energies and the density of states in the vicinity of the pairing transition point are presented. Within the Green function approach model calculations are performed using the thermodynamic $T$ matrix in ladder approximation. As a main r esult the formation of a pseudogap in the level density near the critical temperature of the pairing phase transition has been found. It is shown that compared to mean field, the picture of the onset of the pairing transition is essentially changed if correlations are taken into account.