[en] The systematics of the (E2) ß ray transition energies and the available lifetime data are used to characterize the excitation modes of the light rare-earth nuclei (N greater than or equal to 82) at different spins. The results, which include our recently obtained data on ₁₄₉Gd, ₁₅₄Ho, ₁₅₅Er, ₁₅₇Yb and ₁₅₈Yb nuclei, indicate that, at low spins, the nuclear excitation mode (shapes) change from single-particle excitations (weakly oblate) in N less than or equal to 85 nuclei to quasi-vibrational (soft triaxial) in N = 86, weakly rotational (prolate) in N = 87, and rotational (prolate) in the N greater than or equal to 88 systems. At higher angular momenta, all these nuclei show a general tendency to traverse the (epsilon,ß) plane towards the oblate axis, and to eventually adopt the aligned coupling mode of excitation