Feather Colors Affect Bird Physiology

Feather Colors Affect Bird Physiology


Some interesting research has emerged regarding the effects of feather colors on a bird's internal physiology. So, we're taking a look at what they found, mixed in with a little bird palette inspiration.

It has always been thought that the bird made the color, but now scientist have found that the color of a bird's feathers can have a dramatic impact on a bird's physiology.

"The traditional view is that internal processes of birds determine their external features -- in other words, physiology forms the feathers," said Kevin McGraw, an assistant professor at ASU's School of Life Sciences. "But our results indicate that a perceived change in the color of an animal can directly affect its internal physiological state. A barn swallow's hormonal profile is influenced by its outward appearance."

2518459796_61bc008f19.jpg    Lilac-breasted Rolle
The Lilac-breasted Roller, Coracias caudataus, is a member of the roller family of birds. It is widely distributed in sub-Saharan Africa and the southern Arabian Peninsula, preferring open woodland and savanna; it is largely absent from treeless places. Usually found alone or in pairs, it perches conspicuously at the tops of trees, poles or other high vantage points from where it can spot insects, lizards, scorpions, snails, frogs, small birds and rodents moving about at ground level.

 

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"In the animal world, sexual signals by males -- from the antlers of elk to the gaudy tail feathers of peacocks -- have evolved to convey honest, accurate information about the animal, McGraw said. Evolutionary biologists believe the top males in a population can afford the physiological costs of expressing the most exaggerated forms of sexual signals, like a conspicuous dark feather color that is either biochemically costly to produce or makes those individuals more susceptible to predators, he said."

The experiment was done with barn swallows, whose chests feathers are an identifying trait used to convey status, health and the ability to successfully raise young. Researchers artificially colored the chest feathers of male birds making them darker, then released them back into the wild. After a week the birds were collected once again and given blood tests to measure their androgen levels. What they found was quite surprising an unexpected, by changing the color of the feathers the birds levels of testosterone quickly, and significantly, increased.

741119461_3b12656b30_b.jpg    Painted Bunting
The male Painted Bunting is often described as the most beautiful bird in North America. Its beautiful colors, dark blue head, green back, red rump and underparts, make it easy to identify. The plumage of female and juvenile Painted Buntings is green and yellow-green, serving as camouflage.

The Painted Bunting is found in thickets, woodland edges and brushy areas, along roadsides, in suburban areas, and gardens.[3] Populations are declining on the East Coast where habitat is being lost to development. The breeding range includes Texas, Oklahoma, Arkansas, Florida, Georgia and Louisiana.

 

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"The experimental manipulation didn't just improve the males' looks in the eyes of the females, it actually changed their body chemistry." said lead author Safran.

"The speed with which the internal qualities of the bird were affected by the plumage color manipulation was surprising to me," added McGraw. This suggests a dynamic system, he added, one that "speaks to the complexity of sexual signaling systems and the way people should think about how phenotype interacts with physiology."

714px-european_robin_aka.jpg    European Robin
The European Robin (Erithacus rubecula), or, in Anglophone Europe, simply Robin, is a small insectivorous passerine bird that was formerly classed as a member of the thrush family (Turdidae), but is now considered to be an Old World flycatcher (Muscicapidae). Around 12.5–14.0 cm (5.0–5.5 in) in length, the male and female are similar in colouration, with an orange breast and face lined with grey, brown upperparts and a whitish belly. It is found across Europe, east to Western Siberia and south to North Africa; it is sedentary in most of its range except the far north.

 

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These studies cumulatively show that colors are revealing of the bird's individual qualities," McGraw said. "We previously found that the darker guys were more fit, by fathering more offspring, but still didn't know what made a good, dark male. Here it suggests that testosterone and its associated behaviors are closely linked to a male's color and fitness.

Since the 'currency' of evolution is successfully raised offspring, the message from our work is that darker males, at least in North American populations of barn swallows, are favored over duller ones," Safran added. "The fact that darker males have naturally higher testosterone levels might be a clue as to why they are more successful.

2237123651_315e4b2987.jpg    Chaffinch
The Chaffinch, Fringilla coelebs, is a small passerine bird in the finch family Fringillidae, also called a spink. Its large double white wing bars, white tail edges and greenish rump easily identify this 14-16 cm long species. The breeding male is unmistakable, with his reddish underparts and a blue-grey cap. The female is drabber and greener, but still obvious.

This bird is widespread and very familiar throughout Europe. It is the most common finch in western Europe. Its range extends into western Asia, northwestern Africa, the Canary Islands and Madeira. On Tenerife and Gran Canaria, it coexists with its sister species, the endemic Blue Chaffinch.

 

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The new study is the first to show significant feedback between physical appearance and physiology in birds, and has implications for better understanding the ecology and evolution of physical signals such as feather color, the researchers said.

More Bird Color Inspiration

853080175_0ddc9c4e20.jpg    Dbl-collared Sunbird
The Greater Double-collared Sunbird, Cinnyris afer (formerly placed in the genus Nectarinia), is a small passerine bird which breeds in southern South Africa. It is mainly resident, but partially migratory in the northeast of its range.

This sunbird is common in gardens, fynbos, forest edges and coastal scrub. The Greater Double-collared Sunbird breeds all year round, with a peak from July to November. The closed oval nest is constructed from grass, lichen and other plant material, bound together with spider webs. It has a side entrance which sometimes has a porch, and is lined with feathers.

 

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120426859_5890ddd06e.jpg    Paradise Tanager
The Paradise Tanager, Tangara chilensis is a brilliantly multicolored, medium-sized songbird whose length varies between 13.5 and 15cm. It has a light green head, sky blue underparts and black upper body plumage. The beak and legs are black.

Found in South America, they are fairly widespread and can be seen in Venezuela, Peru, Colombia, Ecuador, Brazil and the upper parts of the Amazon. Paradise Tanager is also found in the lower Amazon Basin, in the northeast, adjacent to the Guyanas, and absent from the central and southeast basin.

 

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Quoted text from: Science Daily

Other Sources: Current Biology, ASU

Header photo by MrClean1982


8 Comments
Showing 1 - 8 of 8 Comments
describing such wonderful colors with only a 4-colours palette is constraining..
Anyway, great work here!
lovely birds... I wish I could see them around here
Your painted bunting looks as if might have been molting. Here is a version that I had done earlier, and have a couple more illustrations.
Painted Bunting
Birds are such fabulous creatures. I love the colours of their feathers.
As I'm formerly a student of ornithology (and still a bird-watcher and artist), this was an extremely interesting article. Great inspiration too!!
Absolutely beautiful! I love this!
These birds are just so lovely. I love how vivid their colors are.
Forest_School_Train
Forest School Training

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