Scrapes, Granaries & Bowers: The Wide World of Avian Architecture   1 comment

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On one April day, a female acorn woodpecker (Melanerpes fomicivorus) was observed drilling an astounding 286 holes into the trunk of a pine tree over the course of nine hours and 27 minutes. Why? So she and her fellow woodpeckers could tuck an acorn into each and every one. The so-called “granary tree” or “nut pole” is used by the group over several years and can eventually have as many as 50,000 holes.

 

DECORATING WITH FLAIR

While a nest, by definition, is a place for the nurturing of offspring, some birds have much more expressive impulses. The male bowerbirds of New Guinea and Australia build amazing “statement architecture” to woo multiple mates (up to two dozen), who then go off and lay eggs in a simple cup nest.

The bowerbirds’ ostentatious creations are made of sculpted grasses and sticks, lavishly decorated with colorful objects such as bones, stone, shells, and bottle caps. Even a spoon, a toothbrush, and a glass eye have been found in some displays. Bits of glass and piles of berries are carefully arranged and color-coordinated and anything out of place is removed in an obsessive frenzy. Depending on the species, the arrays can take the form of an avenue or maypole or even a stage to perform his enthusiastic, and hopefully alluring, dance movements for the females.

Here is a nest built by a satin bowerbird (Amblyornis inornata) and decorated with blue flowers, berries, and bits of plastic.

 

HANGING IN THERE

All of these examples of avian engineering reveal evolution at work. To look closely at bird nests is to glimpse the wondrous ways that species have adapted to particular places, materials, and methods for ensuring the survival of the next generation.

Loss of habitat is high on the list of reasons that bird species are suffering worldwide, and only time will tell whether these architects can adapt their creations quickly enough to keep up with the changes. In the meantime, Peter Goodfellow’s book Avian Architecture is a testament to the beauty of birds and the impressive homes they create.

 

AVIAN ARCHITECTURE

Peter Goodfellow’s recent book, Avian Architecture: How Birds Design, Engineer & Build, captures a lifetime of not just observing birds but the unsung structures they create. Bird nests can be simple or elaborate, as small as a hazelnut, like this hummingbird nest, or enormous, weighing several tons. They can last a few weeks or a century, and can be isolated or one among a half million of similar nests.

Divided into 12 chapters based on types of nests and other avian construction, the book revives Goodfellow’s “schoolboy excitement of ‘bird nesting'” with case studies from around the world accompanied by intricate line drawings and blueprints, as well as hundreds of photos.

“It is the architectural ability of birds to build a variety of nest types,” Goodfellow writes, “that has enabled them to diversify into so many habitats–from the desert to the Antarctic, from high trees to underground, from open ground to out on the water–and which creates some of the best engineered structures in the world.” Inspired by the book, this gallery explores nests around the world.

 

MINIMALISTS…

Some birds do hardly anything at all. Builders of scrape nests do just that: scrape. The bird merely uses its body to nestle out a shallow depression, the negative space of a nest.

Common with birds as diverse as the piping plover, peregrine falcon, and ostrich (as seen above), scrapes, when successful, are deep enough to provide shelter from the elements and the eyes of predators, but high enough to not be chilled or washed away by water.

 

A STITCH IN TIME

With the true weavers of Africa and the New World oropendolas, caciques, and orioles, bird nest-building reaches its most majestic form. Using gymnastic maneuvers, formidable binding, and knots worthy of a sailor in the Royal Navy, these birds create hanging nests that are both strong and flexible. Here, an African weaver straddles its woven swing midway through construction.

In North America, the Baltimore oriole of the East and the Bullock’s oriole of the West can use tens of thousands of stitches in each nest. The female is the primary builder, using her head and beak as a rapid-fire shuttle in the weaving of her avian home, although the male protectively follows her everywhere and sometimes lends a beak, contributing plant fibers or strips of vine or bark.

 

NATURE DID IT FIRST

Before a pair of long-tailed tits (Aegithalos caudatus) set out to make their nest, first they block out a month of time, and then they go about collecting the materials on their shopping list:
– 600+ silk spider cocoons
– 3,000 lichen flakes
– 1,500 feathers
– 200-300 sprigs of moss

This is what Mike Hansell, of Glasgow University, painstakingly determined was needed for the Eurasian bird to build a typical nest, one of the most beautifully formed and skillfully constructed nests in the world.

It takes up to two weeks to build the shell of the structure using the “Velcro principle” of intricate loops of spider cocoon silk wound around bits of moss to support the walls, which can be adjusted for expansion. Another two weeks are needed to line the 5″ nest with a comfortable layer of feathers.

 

SAFETY IN NUMBERS

One-tenth of the world’s birds are colonial, choosing to live intimately with others of their kind. Here, a colony of Laysan albatross (Phoebastria immutabilis) in the Midway Atoll National Wildlife Refuge in the North Pacific Ocean comprises more than 500,000 nests.

Some birds, such as penguins, auks, gulls, terns, and swifts, stick together without much interaction, while cooperative groups such as social weavers work together to build one massive nest in which each pair has a separate compartment.

A third type of colonial bird include passerines such as the Florida scrub jay, in which a few adults build a nest in which a couple females lay eggs, and then the entire group helps to raise the nestlings

 

 

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Posted July 8, 2013 by kitokinimi in Uncategorized

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One response to “Scrapes, Granaries & Bowers: The Wide World of Avian Architecture

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  1. love how creative the birds are in their nest building, instinctivly wise as the bible refers to animals, the skills animals are born with is amazing, we have to learn how to do stuff, while they already know how. I hope they don’tmind if I am a little jealous, lol.

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