  We consider an ecological model consisting of two species of predators
competing for their common prey with explicit interference competition. With a
proper rescaling, the model is portrayed as a singularly perturbed system with
one-fast (prey dynamics) and two-slow variables (dynamics of the predators).
The model exhibits variety of rich and interesting dynamics, including, but not
limited to mixed mode oscillations (MMOs), featuring concatenation of small and
large amplitude oscillations, relaxation oscillations and bistability between a
semi-trivial equilibrium state and a coexistence oscillatory state. Existence
of co-dimenison two bifurcations such as fold-Hopf and generalized Hopf
bifurcations make the system further intriguing. More interestingly, in a
neighborhood of {\emph{singular Hopf}} bifurcation, long lasting transient
dynamics in form of chaotic MMOs or relaxation oscillations are observed as the
system approaches the periodic attractor born out of supercritical Hopf
bifurcation or a semi-trivial equilibrium state respectively. The transient
dynamics could persist for hundreds or thousands of generations before the
ecosystem experiences a regime shift. The time series of population cycles with
different types of irregular oscillations arising in this model stem from a
biological realistic feature, namely, by the variation in the intraspecific
competition amongst the predators. To explain these oscillations, we use
bifurcation analysis and methods from {\emph{geometric singular perturbation
theory}}.
