Reflections in Nature: While serene, nature can also be quite cruel
On a beautiful morning a few days ago, I went out our back door to be greeted by a splash of color from Mary Alice’s flower gardens and the singing of birds — such as the black-capped chickadee, cardinal and phoebe. Sun was shining in a cloudless sky and a gentle breeze was blowing.
All was right with the world and nature. At least that is how it appeared to me.
Who would suspect that this placid scene could have a darker side? However, nature is far from serene. I read in Adrian Forsyth’s book “The Nature of Birds” that, in the bird world, birds can be far from gentle. In one study, a female phoebe, in search of a nest, attacked the nestlings of another female phoebe and pushed the nestlings to the ground. The male parent tried to feed the young on the ground but failed.
The aggressive female took over the nest and began a courtship display, and eventually, the male mated with her. The pair had young of their own. Whatever happened to the original female was not mentioned in the book.
The phoebe belongs to the flycatcher family, with the family’s scientific name of Tyrannidae, from the Latin word Tyrannus and the Greek word Tyrannos, meaning lord or ruler, in allusion to the aggressiveness of members of the family.
House wrens, tree swallows, bluebirds and purple martins have also been known to intentionally destroy eggs and the young of other birds of their same species. This can be done by either the male or the female. In one case, during a two-week period, a female tree swallow destroyed five different nests of other females, killing 25 nestlings.
In one study done on tree swallows, the ornithologist removed the male from its nest site after the pair had hatched out their nestlings; another male quickly flew to the nest, replacing the missing male and then killing the young. The second male then mated and nested with the female. Ornithologists feel that individual birds do their utmost to reproduce their own genes, which is the reason this killing occurs.
When an adult bird or animal kills the young of its own species it is known as infanticide, while the destruction of eggs is called ovicide. Infanticide has been observed in many species, including insects, fish, amphibians, birds and mammals. Infanticide can be practiced by both males and females and is often caused by sexual conflict, with the killer (often male) becoming the new sexual partner, which would otherwise be unavailable. It could also occur for other reasons, such as the struggle for food between females. In this case, individuals could even kill closely related offspring.
Paternal infanticide occurs when a parent kills its own offspring. This sometimes involves consumption of the young themselves, which is termed filial cannibalism. To keep the young bass safe after hatching, the father circles the area to keep them together. This also provides protection from would-be predators. After a few days, most of the young fish will swim away. At this point, the male’s behavior changes, and, instead of defending the stragglers, he devours them as any other small prey.
The black bear has also been classified as a dangerous father. A male bear does not recognize his offspring and is capable of the killing and even the devouring of his own young. In Minnesota, a study was done that showed from 1930-78 there were nine cases of either bear or yearling bear killed by another bear.
In my 34 years as a game warden I only had one case in which a male bear had killed a female bear. The bear was a young female that had given birth to two cubs while in the den. These cubs did not survive, and from the droppings, it appeared that after the cubs died the female ate them. Once out of the den she was immediately attacked and killed by a much larger male bear. It was shortly after this attack that I came upon the scene. It was possible that I chased the male bear away since the female carcass was still there.
I called Gary Alt, a bear biologist, to tell him of my find. He instructed me to set snares around the dead carcass so I could catch the male bear if he returned. I had to return to my home for snares, and while there, I called deputy Harold Haverly for help. Back at the site, we found the male bear had returned and carried the dead carcass away.
This event occurred at the top of Kellogg Mountain, which is covered with thick stands of mountain laurel. I told Harold we should split up and look for the carcass, believing that the male had not taken the carcass very far. Harold was reluctant to walk through the thick mountain laurel, however, I assured him that the male bear would simply run away if we found its location. After searching for 10 minutes, Harold left out a blood curdling scream, and my heart must have skipped several beats.
I ran towards the spot where I thought Harold was and kept thinking that he had encountered the bear. Much to my surprise, I found Harold sitting on a large rock, with his head in his hands. I asked if he was OK and his reply was that he had flushed a turkey out of the laurel. Harold thought it was the bear. We never found the carcass.
To most humans, nature is thought to be serene, and we are often reluctant to acknowledge how cruel our natural world can be.
Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.