We investigate the positive steady states of an age-structured population model with nonlinear density-dependent diffusion, density-dependent fertility, and direct intra-age competition. Treating the mortality intensity \(\lambda \) as the bifurcation parameter, we study the emergence of positive equilibria from the trivial branch. The linearized problem yields a compact strongly positive next-generation operator \(Q_\lambda \) , and the critical threshold \(\lambda _0\) is characterized by \(r(Q_{\lambda _0})=1\) . Using the mortality-driven local bifurcation framework, we obtain a local branch of positive steady states bifurcating from \((\lambda _0,0)\) . A second-order expansion gives an explicit computable quantity \(\Theta _2\) , whose sign determines both the bifurcation direction and the local asymptotic stability of the bifurcating positive equilibria. A Rabinowitz-type global continuation argument yields a global alternative for the real-parameter continuum, while the biologically relevant positive component cannot return to the nonnegative trivial branch except at \((\lambda _0,0)\) . Finally, concrete examples are used to compute \(\Theta _2\) and \(\lambda '(0)\) and to visualize the corresponding bifurcation profiles.
