Competition models with niche for squirrel population dynamics

In this paper we investigate squirrel competition models. More precisely, at first we consider a competition model between red native and grey exotic squirrels, then a model with competition among red native, red indigenous and grey exotic squirrels. We assume that a part of red squirrels can hide in a niche. By adding this hypothesis, we analize if, independently from initial conditions, the grey exotic squirrel population could be prevented from invading the ecosystem and displacing the native populations.