Archive for the 'Essays republished in print media' category

Gender-Bending Chickens: Mixed, Not Scrambled

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Half-sider.
Almost exactly one year ago, hundreds of American birders
were thrilled by sightings and photographs of this remarkable
Northern Cardinal, or Redbird, Cardinalis cardinalis,
photographed in Warrenton, VA.
Image: DW Maiden, 2 March 2009.

This post was chosen as an Editor's Selection for ResearchBlogging.org

I'll never forget the first time I saw a bilateral gynandromorph. I was a bird-crazy teenager reading my way through a stack of avicultural publications when I spied the strangest bird I'd ever seen on the cover of one magazine: an eclectus parrot that was very precisely divided down the middle: one side was rich scarlet and the other was brilliant emerald. Because eclectus parrots are sexually dimorphic -- females are red and males are green -- this remarkable bird was easily identifiable as being composed of both sexes, one on each side.

Even though this was the first time I'd ever seen a gynandromorph, these mysterious birds do pop up from time to time. For example, bird watchers occasionally run across them in the wild (see above photograph) and poultry farmers sometimes find them in their flocks: it is estimated that roughly one in 10,000 domestic chickens -- another sexually dimorphic species -- is a gynandromorph.

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Darwin's Finches Develop Immunity to Alien Parasites

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A male Medium Ground Finch, Geospiza fortis, sits on a tree branch in Ecuador's Galapagos Islands.
Image: Jen Koop.

ResearchBlogging.org

People often view the Hawaiian islands as a tropical paradise, the ideal vacation site, but you wouldn't agree with this assessment if you happen to be a bird. According to a federal report published last year in the United States, nearly all of Hawaii's birds are in danger of becoming extinct due to habitat destruction, competition from imported species and of course, infections by alien disease organisms. In short, this tropical paradise is an ecological disaster area.

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REPRISE: Dead Birds Do Tell Tales

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A young pair of Meyer's Lories (Lorikeets), Trichoglossus flavoviridis meyeri.
Image: Iggino [larger view].

"Can you help us identify a mystery lory in our collection?"
I was pleasantly surprised to find this email request from Donna Dittmann, Collections Manager and Museum Preparator for the Section of Genetic Resources at Louisiana State University Museum of Natural Science in Baton Rouge, Louisiana.

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Plumage Color Influences Choice of Mates and Sex of Chicks in Gouldian Finches, Erythrura gouldiae

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The three color morphs of Gouldian finches, Erythrura gouldiae.
Image: Sarah Pryke, Macquarie University.

ResearchBlogging.org

Gouldian finches, Erythrura gouldiae, are small cavity-nesting passerines that are endemic to open savannahs adjacent to mangrove swamps in northern Australia. These finches eat a variety of native grass seeds, but to meet the increased energetic and nutritional demands of rearing chicks, they primarily eat insects when breeding. Gouldian finches are social birds that typically occur in large flocks in the wild. Invasive species, disease and habitat destruction have dramatically reduced their population so there currently are fewer than 2500 individuals remaining in the wild. But these beautiful birds are popular avicultural subjects so there is an active conservation and captive breeding program designed to preserve them.

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Rosellas, Rings, and Speciation: Testing the Ring Species Hypothesis

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Crimson Rosella, Platycercus elegans.
Image: Australian Broadcasting Corporation.

ResearchBlogging.org

One of the challenges facing those who believe that evolution cannot create new species is explaining the problem of "ring species." Ring species are a group of geographically connected populations that can interbreed with nearby populations, but cannot breed with those populations that exist at each end of the cline (figure A). These populations are known as "ring species" because their populations often form a ring where each end of the cline is located near the other (figure B), or the ends of their ranges actually overlap (figure C), thereby curling inwards upon each other and forming a ring.

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Evolution of the Enigmatic Eclectus

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Elektra, my female Solomon Islands eclectus parrot, Eclectus roratus solomonensis.
This is the smallest and most distinctively marked of all the subspecies of eclectus parrots.
Image: GrrlScientist 4 July 2008 [larger view].

ResearchBlogging.org

Some of you might recall the recent story about scientists learning to identify plumage coloration from fossilized feathers. This might seem a sort of esoteric pursuit meant to entertain scientists with access to big and expensive machines, but in fact, knowing the color of a bird's plumage is very important for learning something about their natural history. Let me explain.

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Lovebird Behavior: Nature or Nurture?

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Peach-faced lovebirds, Agapornis roseicollis (left)
and Fischer's lovebirds, Agapornis fischeri (right),
can interbreed to produce sterile offspring.
Images: LoveBirds New Zealand.

ResearchBlogging.org

Is behavior genetically "programmed" or is it the result of learning? Or is it instead a little bit of both? This is the old "nature versus nurture" argument that has occupied behavioral and evolutionary scientists, psychologists and even the general public for decades. Interestingly, nearly 50 years ago, a series of elegant experiments by an ornithologist and aviculturist revealed that, in lovebirds, at least, nest-building behavior has a very strong genetic component combined with surprisingly little experiential modification.

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Why Grandmothers?

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Seychelles warbler, Acrocephalus sechellensis.
Image: J. Komdeur.

ResearchBlogging.org

When talking about evolution, some people have wondered aloud about why grandmothers exist in human society since they clearly are no longer able to reproduce. However, these people are conveniently overlooking the fact that grandmothers perform a valuable service; they help their relatives, often their own children, raise their offspring -- offspring that are genetically related to them. But curiously, grandmother helpers have not been documented to occur in birds, where most of our research into cooperative breeding systems occurs, so this makes the question even more intriguing: Why are there no avian grandmothers? Further, since cooperatively breeding birds are relatively long-lived, grandparental care should indeed be identifiable, especially if cooperatively-breeding bird societies are observed long enough.

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The Birds of Chernobyl: Better Off Drab and Lazy

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Normal Barn Swallow (a),
while the other pictures show signs of albinism (white feathers; b & c),
unusually colored feathers (d), deformed beaks (e & f), deformed air sacs (g),
and bent tail feathers (h & i).
Images: Tim Mousseau.

ResearchBlogging.org

Twenty years after the Chernobyl reactor disaster, which released clouds of radioactive particles in April 1986, the uninhabited forests within the 19 mile (30 kilometer) "exclusion zone" around the disaster site are lush and teeming with wildlife, giving the appearance that nature's wounds are healing. However, to the trained eyes of the naturalist, something is seriously wrong here.

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Elusive Smiling Bird Rediscovered

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This male Recurve-billed Bushbird, Clytoctantes alixii, was recently photographed by ProAves staff, Adriana Tovar and Luis Eduardo Uruena. This is the first time this globally endangered species has been captured on film. [larger].
[listen to this species' song]

For the first time ever, an elusive recurve-billed bushbird, Clytoctantes alixii, has been photographed in the wild. The bird, recently rediscovered by scientists in Colombia a Colombian ornithologist named Oscar Laverde after a 40-year absence, has a heavy, upward-curving beak that gives it the illusion of an enigmatic smile.

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