Bird Calendars

NOTES FROM NATURE

By Jerry Toll

Consider the Bowerbirds

Now this is a family of birds I can relate to. They are builders, artists, dancers, painters, and individualists. Am I anthropomorphizing? Yes, flagrantly so, but I will offer these observations in my defense.

The bowerbirds, with 8 species in Australia and 18 species in New Guinea, make up the family Ptiloinorhynchidae. As builders, they are unique in the bird world.

The males of each species construct mating grounds to attract females. For the Spotted Bowerbird, it's a simple avenue (bower). The male constructs a tightly woven horizontal mat of grass or twigs. He then weaves vertical twigs into the mat so that they form an arch over a central straight pathway or avenue. After this he finds white objects such as bits of bones, rocks, and snail shells and places them, carefully, to one side of the avenue.

The male of this species favors white objects and rejects red, yellow, and blue objects. However, he then masticates something that when mixed with his saliva produces a reddish substance he paints onto the objects in the bower.

The female enters the avenue and looks through it to the placement of the white objects. Meanwhile the male is watching, somewhat hidden. If the female likes what she sees, she signals the male, he reveals himself and does a little dance, sometimes with a song. If she still likes what she sees, they leave the bower and mate.

His part in the continuation of the species is to attract as many females as possible to his bower, retain them and mate. If he fails to do this, his genes will not be passed on and will eventually die out. In other words, how well he expresses himself determines the survival of his gene pool. I'll come back to this.

Most species of bowerbirds are polygynous. Of these, the complexity of the bower construction is inversely related to the elaboration of the males' breeding plumage. The genus of Gardener Bowerbirds produces larger and more elaborate structures. Due to lack of space, I wont' describe each of the species' bowers, but they have certain characteristics in common. For each of the species, the form of the bower is hard-wired in their brains, but the selection and placement of objects is highly variable and seems extremely important to the success of the enterprise.

I had the pleasure of watching a PBS Nova program on the bowerbirds presented by David Attenborough, which led to this article. What struck me as fascinating when I watched the Gardener Bowerbird arranging his arena was his "expression," if I may use that word, or perhaps his body language.

I have seen that same expression on the face of an artist during the act of creation. It posed this question, "Is this bird demonstrating artistic expression?" Or, conversely, is there an instinctual predisposition to artistic expression that humans share with other creatures on our planet?

The most basic definition of art is a creative act by an individual. This has been attributed exclusively to humans in the past, but behavioral biologists and cultural anthropologists have been chipping away at the wall that separates the attributes of humans and animals.

Let's not forget the role of the female in this drama. The female as well as male of each species has developed artistic inclinations. It is she who must have the discerning eye. It is she who determines whether the elaborate preparations the male has made for her are acceptable. She determines successful mating. In doing so, she reinforces the genetic predisposition of the practice.

What have these elaborate mating rituals to do with survival of the species? Very little, it seems. She takes full responsibility for rearing young. She determines whether the species will continue to reproduce itself in sufficient numbers to thrive.

There are many things creatures do even though related to reproduction that are seemingly frivolous or unnecessary, sometimes even downright contradictory.

I think this is Nature's way of saying that orderliness is elusive. That, yes, there is order in the universe but it is not linear. We must search for it in creative ways, ways that might make no sense until we make the slender connection.

The purpose of the bowerbirds' mating rituals is to provide uniqueness. It defines the species. It tells them who they are.

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