Life and death in the natural world

Last week, I found two birds on the sidewalk. They were less than a day old, featherless, tiny and dead. It’s that time of year when many are born and many die. Nature might look cruel to us at times, but it’s efficient and it works.

Animals that have short lives reproduce like, well, rabbits for a reason. Female mice, for example, can become pregnant at 25 days old, give birth after 20 days and become fertile again within 24 hours. Talk about a need for family planning

Predators, especially large ones, can take years to mature, then many months to reproduce and raise young. Too many predators and not enough prey end up with predators dying of starvation. But too many prey and they starve to death because they’ve eaten all available vegetation. It happens.

Biologists would use words like homeostasis, which means a system in balance or equilibrium. For the rest of us, examples work better, like the snowshoe hare and lynx of the northern forests.

Hares reproduce quickly and can build a population fast. Lynx, a wild cat, eat hares, reproduce more slowly and have fewer offspring. When there are few lynx, the hare population increases. That leads to lynx having larger litters that survive to adulthood and need more food.

One day there are too many lynx that eat too many hares. Then both populations decrease, hit bottom and start to build again. Neither population gets too big as the predator and the prey keep each population in balance.

Our problems accepting what seems to be an animal’s untimely death begin when we place human values on animals. It’s hard but important to focus on the survival of a species more than the survival of an individual animal. That doesn’t mean not to care. It means to try to see the big picture.

Ducks lay a lot of eggs. Some hatch, some are eaten by skunks and snakes, some never hatch because of wet weather. Or a fox eats the hen.

Those that hatch have to make it to water quickly. Some make it, some are eaten by ravens and raccoons, some get run over by cars.

Those that make it to water have to eat and grow to migrate in the fall. Some make it, some are eaten by mink and gulls, some die of disease.

The point here is that a young bird’s life is fraught with danger. Many eggs are laid but few survive to become birds and fly away. If a robin lays four eggs, two will survive the approximately 28 days from egg to hatching to nestling to flying.

However, a world where every robin’s egg hatches and lives to adulthood would quickly be unbearable. That’s why many small bird species don’t live more than two years.

Those two dead birds on the sidewalk? They ended up feeding nature’s scavengers. Sad, but in a way part of the big circle. Equilibrium. Homeostasis.

Bruce Auchly is the Montana Fish, Wildlife and Parks Region 4 information officer.