On one of our beautiful spring mornings, I walked out our back door to be greeted by a splash of colors from my wife Mary Alice's flower gardens - birds, such as black-capped chickadees, cardinals and phoebes, singing; sun shining and a gentle breeze blowing. All was right with the world and nature. At least that is how it appeared.
Who would suspect that this placid scene would have a darker side? Nature is far from serene.
I read in Adrian Forsyth's book "The Nature of Birds" that 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 threw them 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. Eventually, the male mated with her, and 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, which is in allusion to the aggressiveness of members of the family.
House wrens, tree swallows, bluebirds and purple martins also have been known to intentionally destroy eggs and the young of other birds of their 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 nests of other females, killing 25 nestlings.
In one study done on tree swallows, the male was removed from the 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 that killing occurs.
When an adult bird or animal kills the young of its own species, it is called infanticide. 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 often is caused by sexual conflict, with the killer (often male) becoming the new sexual partner, which would otherwise be unavailable.
It also can occur for other reasons, such as the struggle for food between females. In this case, individuals even can 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.
After young bass hatch, the father guards the area, circling around and keeping the young 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 treats them as any other small prey and devours them.
The black bear also has been classified as a dangerous father. A male bear does not recognize his offspring and is capable of the killing and even devouring of his own young.
In Minnesota, a study was done that showed from 1930 to 1978, there were nine cases of either bear or yearling bear killed by other bear.
We humans often are reluctant to acknowledge how cruel our natural world can be.
Bower retired after 34 years as a wildlife conservation officer for the state Game Commission. He has published several books about his experiences. Questions and comments may be sent to him at 153 Redington Ave., Troy PA 16947.
