Properties of solutions of a class of equations with lag which describe the dynamics of change in the population of a species with the age structure taken into account

The equation
$$ \dot N=r\biggl[1-\dfrac{1}{K}\int_{h_1}^{h_2}H(s)N(t-s)\,ds\biggr]N, $$
generalizing the well-known Hutchinson equation, is used to describe the dynamics of change in the population of a species, with the age structure taken into account. Conditions are found for bifurcation of a periodic solution of this equation. The results obtained here are applied to explain some natural phenomena.
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