Satin Bowerbird (Ptilonorhynchus violaceus) in bower by Ian

An interesting article from News to Note – Sept 18, 2010 issue talks about the Bowerbird and it’s ability to use special optical effects. The article is discussing Physorg.com’s information on the elaborate bowers the bird makes.

“Bowerbird males are well known for making elaborate constructions, lavished with decorative objects, to impress and attract their mates. Now, researchers reporting online on September 9 in Current Biology have identified a completely new dimension to these showy structures in great bowerbirds. The birds create a staged scene, only visible from the point of view of their female audience, by placing pebbles, bones, and shells around their courts in a very special way that can make objects (or a bowerbird male) appear larger or smaller than they really are.” (Physorg.com)

The scientist are trying to figure out about this aesthetically appealing ability. They noticed that the bird places articles from smaller to larger as the bower is approached. When they rearranged the articles, the Bowerbird changed them back. He is trying to give an allusion they think.

Spotted Bowerbird (Chlamydera maculata) by Ian

News to Note concludes with this:

“Evolutionists often seek to find natural explanations for distinct human aspects like aesthetics, moral consciousness, and self-consciousness. The bowerbirds’ apparent art appreciation seems to allow the most genetically fit to survive according to biologist Gerry Borgia of the University of Maryland. But do male bowerbirds intellectually conceive the idea of the optical illusion, and do female bowerbirds intentionally judge the design as artistic?

Rather than an intellectual intention towards art, the great bowerbird instinctively builds remarkable structures, and the female instinctively responds to the optical effect, as programmed by the Creator. Only man, created in the image of God, has a true aesthetic sense. When appreciating the beauty and design of creatures like the bowerbird, the wise aesthetic judge praises the Creator of both art and beauty.”

The two articles are interesting and of course, the one from Answers in Genesis, News to Note – Sept 18, 2010, issue gives the creationist view of this.

From another article:

” the male bower bird, an accomplished avian architect that has long fascinated scientists with its remarkably complex courting behavior. Instead of using just showy plumes or a romantic melody to attract a mate, the pigeon-sized bower bird constructs an elaborate structure — a bower — on the forest floor from twigs, leaves, and moss. It then decorates the bower with colorful baubles, from feathers and pebbles to berries and shells.”

“The bowers aren’t nests for raising kids; they are bachelor pads designed to attract and seduce one or more mates. When a female arrives to inspect the bower, the male struts and sings. He hopes to convince her to enter the bower, where mating takes place….they are of special interest to scientists seeking to understand how such complex traits evolve and function.”

Golden Bowerbird (Prionodura newtoniana) at bower by Ian

“Each builds its own shape of bower and prefers a different decorating scheme. A few, for instance, surround their bowers with carefully planted lawns of moss. Others have been known to steal shiny coins, spoons, bits of aluminum foil — even a glass eye — in an effort to create the perfect romantic mood. Some, like the iridescent blue Satin bower bird, the star of Bower Bird Blues, even “paint” the walls of their structures with chewed berries or charcoal. For the male Satin, which builds a U-shaped bower from parallel walls of twigs, the favored color is blue. To decorate its “avenue,” as scientists call it, he collects blue feathers, berries, shells, and flowers. While some of these decorations are found in the forest, others are stolen from the bowers of other males; young males, in particular, are prone to this petty thievery. However obtained, the precious knickknacks are then scattered around the bower. The male then waits, passing time by constantly fine-tuning his structure and rearranging the decorations. (from Nature)

And God blessed them, saying, “Be fruitful and multiply, and fill the waters in the seas, and let birds multiply on the earth.” (Genesis 1:22 NKJV)

That verse answers it for me. God created them with that “complex trait.”

Information about the Bowerbird:

They are in the Ptilonorhynchidae – Bowerbirds Family of the Passeriformes Order. There are 21 species in the family in 9 different genus. There are 3 Catbirds and an Piopio included in the family.

Bowerbirds and catbirds make up the bird family Ptilonorhynchidae. These are medium-sized passerines, ranging from the Golden Bowerbird (22 cm and 70 grams) to the Great Bowerbird (40 cm and 230 grams). Their diet consists mainly of fruit but may also include insects (fed to young), flowers, nectar and leaves in some species.

The bowerbirds have an Austro-Papuan distribution, with ten species endemic to New Guinea, eight endemic to Australia and two found in both. Although their distribution is centered around the tropical regions of New Guinea and northern Australia, some species extend into central, western and southeastern Australia. They occupy a range of different habitats, including rainforest, eucalyptus and acacia forest, and shrublands.

Bowerbirds are most known for their unique courtship behaviour, where males build a structure and decorate it with sticks and brightly coloured objects in an attempt to attract a mate.

The catbirds are monogamous and raise chicks with their mate, but all other bowerbirds are polygymous, with the female building the nest and raising the young alone. These latter species are commonly sexually dimorphic, with the female being more drab in color. Female bowerbirds build a nest by laying soft materials, such as leaves, ferns, and vine tendrils, on top of a loose foundation of sticks. They lay one or two eggs, which hatch after 19 to 24 days, depending on the species.

The most notable characteristic of bowerbirds is their extraordinarily complex courtship and mating behaviour, where males build a bower to attract mates. There are two main types of bowers. One clade of bowerbirds build so-called maypole bowers that are constructed by placing sticks around a sapling; in some species these bowers have a hut-like roof. The other major bowerbuilding clade builds an avenue type bower made of two walls of vertically placed sticks. In and around the bower the male places a variety of brightly colored objects he has collected. These objects — usually different among each species — may include hundreds of shells, leaves, flowers, feathers, stones, berries, and even discarded plastic items, coins, nails, rifle shells, or pieces of glass. The males spend hours arranging this collection. Bowers within a species share a general form but do show significant variation, and the collection of objects reflects the biases of males of each species and its ability to procure items from the habitat, often stealing them from neighboring bowers. Several studies of different species have shown that colors of decorations males use on their bowers match the preferences of females.

In addition, many species of bowerbird are superb vocal mimics. Macgregor’s Bowerbird, for example, has been observed imitating pigs, waterfalls, and human chatter. Satin bowerbirds commonly mimic other local species as part of their courtship display. (Wikipedia)

(Information from various Internet sources.)
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Articles here on the Blog about Bowerbirds:

Golden Bowerbird by A.J.Mithra
Ian’s Bird of the Week:
Tooth-billed Bowerbird
Spotted Bowerbird
Golden Bowerbird

More Formed By Him articles

Family#126 – Ptilonorhynchidae
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