91热爆

After a year with a bumper crop of pine seeds, many voles will survive until the spring. When this happens the population will surge as they breed at an extraordinary rate. Four weeks after having her first family a female is pregnant again. She will soon abandon her first family and start a new one. Unfortunately for them, all the owls in the forest - including the Tengmalm's owl - eat voles. The number of voles will build for about five or six years then the population will crash as there will be too many of them for the limited supply of food. This in turn affects the owl population since owls can raise more chicks if there are more voles to eat. And as the number of owls increases, so they spread out into new territory.