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feathers - a book review

Surprisingly, Thor Hanson begins his treatise on feathers with a titillating introduction that describes the role of birds in shamanism and ancient mythologies, and he goes on to speculate why most religions share a belief in angels as intermediaries on a flight path toward unity with God. But from there on, the reader encounters a definite shift of tone. The remainder of the book follows three themes: the evolution of feathers, their biological utility to flight and life functions, and the commercial use of feathers.

As someone who has persistently bypassed the dinosaur articles in National Geographic as being the epitome of ennui, I was totally engulfed by Hanson’s lucid discussion of Archaeopteryx studies in unraveling the evolution of feathers. (Archaeopteryx was a pre-historic linchpin having physical properties of reptiles and birds.) Traditional theories argue that feathers evolved for the purpose of flight. Others proposed non-aerodynamic proto-feather structures that facilitated the insulation, waterproofing and display and courtship colors, were the first to appear.

But more recent studies jettison origin from reptile scales or the multiple potential uses of the emerging new feather form. Instead, they focus on a how a feather grows, as the key to answering questions as to how feathers evolved. Hanson very carefully, with precise diagrams, details the five states of feather development. This theory attempts to overcome the confounding discordance of the structural difference between flat scales and tubular feathers. Though initially speculative, this theory has received profound support from numerous fossils exemplifying the five stages, unearthed by paleontological studies in northeast China in the 1900s.

Secondly, Hanson discusses the physiological properties of feathers, and their numerous survival functions. Although feathers are composed of keratin, as are our hair, nails and skin, it is a chemically unique keratin providing the molecular basis for particular characteristics: strong yet light, firm yet flexible, durable and elastic. Each individual skin follicle can produce all the feather types and colors over a lifetime, from natal down to juvenile, adult, and breeding plumages. Each follicle is modulated by muscles and nerves that give a finely tuned agility to individual feathers. Likewise, molting is more than a random, diffuse shedding. It occurs in a staggered pattern from innermost primaries out to wing-tips, although in ducks the molt can take place more precipitously, leaving them rather helpless in hunting season, giving rise to the phrase “sitting duck.”

Besides physiological molting, birds can release a mass of feathers in a moment of stress or fright, leaving a predator with a feathery mouthful. Although feathers also provide insulation, they are positioned in clusters or tracks with in-between bare patches, providing for cool drafts and evaporation.

The third major theme is man’s commercial use of feathers. Of course, the author is obliged to briefly cover the pre-World War I global “plume-boom” (which gave rise to the Audubon Society), but Hanson has also dug up tales of ostrich magnates and African ostrich espionage! He also points out that although women were the feather industry’s principle market, women founded nearly every local Audubon chapter and made up most of the early membership.

Hanson undertook several excursions to investigate the current feather market. He visited the only remaining New York City milliner, who handcrafts here artisan ally designed hats. After several reassurances of his purely academic interest, he is finally given a tour of the “The Rainbow Feather Company” where feathers are dyed in a secretive industrial process. He also inveigles an interview with the producers of “Jubilee!,” the most extravagant show in Las Vegas, followed by a visit to backstage storage replete with elaborate feathers costumes.

However, present uses of feathers go beyond the commercial uses that serve our vanity. “Biomimetics” is a recent approach to scientific innovation whereby researchers go back to nature, now with very high powered microscopes and digital instruments, to look for high-tech ways to mimic what nature has accomplished superbly on its own. As I alluded to previously, birds can instinctively, independently, move individual feathers in a much nuanced response to wind conditions in order to manipulate speed, orientation, etc. A specific example is soaring birds’ adjusting their wing-tip “fingers” as needed. Engineers have closely studied birds and devised artificial “winglets” that have been added to the tips of plane wings to increase flight efficiency. They have been found to decrease fuel use by 6%.

This just skims the surface of the revelations in Feathers. The evolution research chapters are clear and accompanied by explanatory diagrams. Hanson’s junkets exploring commercial uses of feathers are lighter reading, with a sprinkling of humorous anecdotes.

Check out this month's issue of National Audubon for an article on feathers by author Thor Hanson and beautiful photos of feathers by Robert Clark. Click here to read the article.

For a great winter read, you can check this book out from the Rutland Free Library and the Brandon Library.



book review: oology 

Verreaux's Eagle, an African birdRalph Handsaker (1886-1969) was an Iowa farmer, wood carver, carpenter, hunter, fisherman, taxidermist and oologist - egg collector. Carrol Henderson, the author of Oology, an ornithologist and avid nest collector (he has a species "nest list" of 500) became aware of Ralph Handsaker via his brother, who found out that an old farmhouse in Iowa, that belonged to the great-grandfather (Ralph Handsaker) of John Handsaker, was to be re-opened and restored for the grandson and his new wife. Thus, Ralph's egg collection, which had been in the farmhouse, neatly arranged in cabinets he had made, was rediscovered. The author was invited to survey the collection and see to its disposition.

The heyday of oology was 1880-1918. It began as a hobby among bird enthusiasts in England in the mid to late 1800s, and then crossed the Atlantic to North America.

There were three main types of egg collectors. The market egger collected large numbers of wild bird eggs for commercial use and personal profit. Eggs were sold in markets and restaurants for human consumption. This was especially profitable near the seacoast where there were nests of gannets, auks, gulls, albatrosses, puffins, and murres. A notable example is Laysan Island, near Hawaii, which had large colonies of albatrosses. The albumen of their eggs was used to make albumen prints when exposures on glass plates were used in photo development.

A second group were young boys who collected eggs for fun. Most were destroyed, but for a few it led to a lifelong interest in wildlife, such as Franklin Delano Roosevelt.

Lastly, there were true oologists who collected and accumulated bird eggs using a standard protocol for preserving, identifying and labeling eggs and documenting nest data. Braving swamps, tall trees, dangerous seas and hostile natives, they were intrepid venturers. A few lost their lives in the quest. Ralph was quite determined. He devised a twelve-foot wooden ladder with a curved flat iron hook bolted to the top to hook over a tree limb. His collection consisted of 4,000 eggs. No laws protected birds, their nests or eggs in that era.

Stanley Crane, another African birdMost oologists would collect the entire clutch because birds most often re-nest, though the second clutch usually had fewer eggs. Hundreds of eggs was not unusual for a good day of collecting. To lighten the load home, the oologist often blew out the egg in the field (this is necessary in any case for preservation). A small drill head was used to bore a hold in the egg. With a tiny blowpipe, a high pressure stream of air entering the holde forced the contents of the egg out.

As ink pen was then used to place data in a standard manner around the hole. The first number above the hole was the reference number of the American Ornithologist's Union for the species. The second number is written as a fraction. The top number was the "set mark" - the number of nests of that species collected on a particular day, under which was the number of eggs in that particular nest. Lastly, the date was recorded.

Eggs were stored in cabinets with drawers (sunlight would fade the colors), in cedar sawdust to keep insects away.

To supplement their collections, oologists often traded or purchased eggs. The author lists the 1904 value of Ralph's eggs. Most were less than $1, but the Great Auk egg could go for $1,600.

As early as 1831, in England, oology books had notable wild bird egg drawings. These, however, were not field books, but collectors' volumes of considerable value. Characteristic egg and nest paintings, many by famed bird artist Louis Agassiz Fuertes, were featured on bird trading cards, a popular premium in Arm and Hammer baking soda boxes. The author considers these cards to be America's first handy reference for identifying wild birds. Another type of publication was the 1904 "Taylor's Standard American Egg Catalogue," 98 pages of values for birds' nests and eggs. It served as a resource for trading and selling eggs, nets and stuffed birds. A typical ad is the following:

W. H. Bingham, Algoma, Iowa, Box 151: Collection of nests and eggs. Specialty - waders and warblers. Exchanges desired. Will purchase sets of above if reasonable. Must be from original collection.

Another section of the book covers egg classification. There are four basic egg shapes: ellipitical, pyriform, oval, and subelliptical. Since there are short, medium and long sub-categories, twlve different egg shapes are possible. The pigments, porphyrins, that create the colors, are prodcued by the breakdown of hemoglobin from ruptured blood cells, which are deposited on the egg as it traverses the oviduct and uterus. White eggs are found in species that nest in tree cavities or burrows where eggs are not visitble to predators. Patterns are classified as dotted, blotched, marble, overlaid, splashed, spotted, streaked or scrawled. There is great variation in markings that occurs within a single species and sometimes within a single clutch of eggs.

Egg collecting became illegal after the passage of the federal Migratory Bird Treaty Act of 1918.

After the background information on the history of egg collecting, Carrol Henderson spotlights sixty of the nearly 500 species present in the Handsaker collection. They were donated to the Peabody Museum of Natural History at Yale University in 2006.

These old collections are more than historical curiosities. The data they contain can reveal changes in species habitat, distribution, nesting sites and clutch size. Morphological measurement of egg size and shell thickness and chemical analysis of shells and their dried inner membranes can reveal the presence and effect of pesticides and heavy metals. DNA analysis is a burgeoning field of study.

Oology is fascinating reading. The numerous photographs, drawings and paintings are exquisite. The book is available through inter-library loan from the Rutland Free Library and, of course, from your local independent bookseller, and I presume, online resources.



looking for a new field guide?

The latest entry into the world of field guides is Don and Lillian Stokes’s The Stokes Field Guide to the Birds of North America. This comprehensive volume may not be one all birders want to carry into the field, as it is just shy of 800 pages. However, many of us didn’t flinch when David Sibley published his massive volume. While it may remain at home for some, others will probably find it useful enough to keep it handy in their cars.

lots of photos in a field guide is helpful when identifying gullsThe guide contains superb photos showing various plumages for each species. Most the photos give additional information such as where it was taken and at what time of year. This is helpful in determining whether feathers are fresh or worn, or if regional variations occur.

Content includes the most up-to-date regional maps, the American Birding Association’s (ABA) rarity rating for each species, and information on wild hybrids. It also includes the most recent additions, deletions, splits and lumps, and changes to common and scientific names. For example, according to Lillian Stokes, the book was updated to include the recent split of Winter Wren (into Pacific Wren and Winter Wren) just before it went to press. 

A bonus of the new field guide is a downloadable CD of 600 calls and songs of 150 common birds, as well as photos.

With the size of the book and all the color photos and the CD, I was surprised that it sells for around $24.99 (less at some online retailers). With the holidays around the corner, this might be something to give to a favorite birder in your life or put on your own wish list. Studying the great photos will be a great way to spend the winter.


book review: Summer World by Bernd Heinrich

In Summer World, Bernd Heinrich completes his inquisitive survey of seasonal adaptations that he inaugurated in Winter World (reviewed in fall 2008 newsletter).

Upon opening the pages, one’s sense of touch is aroused by the unusually softly textured paper. How perfect, I thought, for those of us with a bent to cozy up for a winter’s evening reading and dreaming warmer climes and times. Whether this will also be true of the paperback edition coming out in April, I cannot say. The back cover flap says it’s also available as an e-book. Sorry, no sensual accompaniments there!

Although it is entitled Summer World, Heinrich’s observations do not begin at the summer solstice (June 21), but rather in February, when he first sights a raven pair building a nest. He points out that, though we tend to think of winter, with its test of severe cold, as necessitating months of preparation, the few truly warm weeks of summer are a limited time for successfully mating and raising young. American RobinSo birds, insects and amphibians, all get as early a start as possible to take advantage of the warmest days. Also trees, for one might say they are “obsessive” about preparation, since they flush out early, complete their yearly growth shortly thereafter, and by July, have developed buds for the next year.

I found his further discussion of tree budding particularly enlightening. Many of us have found mid-winter bud identification workshops and field trips quite frustrating. Now, to make it more perplexing, Heinrich alerts us that many northern forest trees have separate buds for leaf and flower. There is a logical utility for this. Wind-pollinated trees flower a month before leafing out, when they can be more easily pollinated because there is less blockage of wind carrying pollen over leaves. On the other hand, bee-pollinated basswood is pollinated a month or so after the leaf buds have opened, when, in late summer, the bee population has peaked.

BloodrootAs in Winter World, the author relates his ingenious yet practical methods for evoking nature’s secrets. Using garbage can lids, he studies crocuses’ response to light, and to consider Bloodroot’s blooming relation to temperature, he puts them in his refrigerator.

A large part of the book is given to discussing insects. He delves into great minutiae on the distinct nests and unique behaviors of various wasp species and wonders, “Aside from the mystery of how wasps can do so much with so little, there is the mystery of how what they know, is passed faultlessly from one generation to the next.”

Seemingly instinctual behavior of some moths and butterflies can appear positively perspicacious. Their caterpillars chip off the petiole of the leaf they have just partially consumed, allowing it to drop to the ground. Heinrich calls this “covering their tracts,” from buds on the lookout for caterpillar activity.

However, I found the author occasionally spotty on the lucidity of his explanations. For example, a seven-page dissertation explores red and black ant colonization, emigration and social interaction. Yet,Baltimore Checkerspot caterpillar in a subsequent chapter, in one paragraph, he describes a sphinx moth caterpillar that overnight became “covered with 91 white braconid wasp cocoons, its skin covered with little dark puncture wounds.” There is a rather ghastly photo of this phenomena, but not explanation. Had the caterpillar ingested wasp eggs during prior days when Heinrich had been watching it casually munching leaves? For someone who is professor emeritus of biology at the University of Vermont, the answer is probably something he considers quite commonplace.

The author redeemed himself, in my estimation, by providing an answer to something that struck my curiosity this past fall. On many golden leaves of a neighbor’s poplar, I noted a dime-sized deep green splotch, at the base, near the mid-vein. Heinrich put similar spotted areas under a microscope and found feeding “leaf miner” caterpillars with trails of black fecal pellets.

As distinct from Winter World, in Summer World Heinrich takes more excursions off course into philosophical speculation. In sequential chapters, he hypothesizes on the possibility of life on other planets, presents a diatribe on global working that leads into the necessity of a “spiritual imperative,” and theorizes how man evolved from a “hairy” ape into a “naked” human.

All in all, I was less enamored of this book than Winter World, even though the text is accompanied by beautiful and clarifying drawings and watercolors, which I always consider a plus. On the contrary, entomologists and other insect enthusiasts would be enraptured. Perhaps this is because, despite being so numerous, insects are more inconspicuous, often considered a nuisance, and requires time, patience, and close observation to understand the intricacies of their lives.

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