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Flowers throw an unexpected curve at Mrs. Gould’s Sunbirds in the form of nectar spiked with bitter toxins. https://goo.gl/T6UcEI

The sunbird with a hook bill co-evolved with similarly shaped flowers. But more than half of the world's flowers add toxic chemicals to their nectar. Scientists are only beginning to understand how these bitter-tasting meals affect the birds and insects that consume them.

These chemicals are part of the newly appreciated reality of sunbirds. These beauties can be enjoyed on spring trips to Bhutan and Myanmar. (I recommend a 2-week tour led by an experienced local guide working with an international birding tour company.)

On these trips, watch for Mrs. Gould’s Sunbirds at the corolla tubes of nectar-rich flowers. The length and shape of the tubes function as “exploitation barriers” to shorter-billed birds. However, some birds take nectar without providing pollination services. They either force their way into the flower opening or stab a hole in the base of the flower. Sunbirds chase them away.

Sunbirds guard floral gardens of red, orange, yellow and white. However, if the sunbirds suddenly depart, the nectar volume inside a flower tube can increase 10-fold. At some point the robbers return.

Read more – https://goo.gl/T6UcEI
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eBirders and an army of ringers have discovered distinct migration routes used by 2 Palm Warbler subspecies. http://goo.gl/f8N3Df

There are over 100 million observations of thousands of species in the eBird online database, and those of the Palm Warbler have collectively helped make a new citizen-science discovery.

An eBird data animation clearly shows that an initial southern fall surge of one subspecies of Palm Warbler from western Canada is followed many days later by a second surge from the subspecies that breeds in eastern Canada.

Both subspecies migrate in the fall in compact flocks to the U.S. Southeast, southern Mexico, Belize, Honduras and the Caribbean islands.

Read more – http://goo.gl/f8N3Df

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The unmatched promiscuity of Superb Fairy-wrens is increasingly seen as the result of a blend of color signals displayed by brightly colored males and the songs of less colorful females. http://goo.gl/tt8lzW

The species is Australia’s black, white and blue dabs of iridescence in the bush.

Fairy-wrens, like other birds, use “extra-pair” sex as an important part of their reproductive strategy. Female fairy-wrens sing to stake territorial claims, and scientists are decoding how some of those musical claims are stronger than others.

The promiscuity of Superb Fairy-wren females is unique among all songbirds, or members of the Passerine order. Female fairy-wrens pair with a dominant male, but allow less dominant male “helpers” to participate in the feeding and care of her offspring. However, the paternity of fairy-wren offspring is not what scientists expected: 76% of a female’s chicks are sired by males outside the family group.

“This is the highest known frequency of extra-pair paternity of any bird,” a team of Australian and British scientists reported in the journal Molecular Ecology. Since that landmark 1997 study, many others using genetic-fingerprint analyses of chicks and eggs have measured various rates of “extra-pair paternity” in virtually all songbirds.

Read more – http://goo.gl/tt8lzW

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The Common Blue Tit, one of Europe’s most attractive and recognizable birds, has an image problem perpetuated in field guides. http://goo.gl/Em4ZiB

Bird book photos show nearly identical photos of male and female tits, but the birds don’t see it that way. Field guides, avian research and descriptions of bird behavior reflect a bias in favor of the human's-eye view of birds, not the birds’-eye views of themselves.

To Blue Tits, the crowns of male birds strongly reflects ultraviolet light while female crowns are much duller in UV reflectance. Since humans can’t see UV light this difference in the crowns is invisible.

“In avian terms, the Blue Tit is misnamed and should perhaps be considered a UV Tit,” a team of British researchers wrote in Proceedings: Biological Sciences.

Of course, field guides do an excellent job in helping birdwatchers identify species. However, most, if not all birds wouldn’t recognize themselves in those guides.

Read more – http://goo.gl/Em4ZiB

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Unrelated pairs of Taiwan Yuhinas share one nest, parenting, defense and even genes, using cooperation to evolve. http://goo.gl/AQzNJJ

Their breeding tactics reveal a weakness in the standard evolutionary theory of “kin selection” that ignores the advantages of cooperation between unrelated individuals.

An ornithologist 80 years ago noticed that the eggs in each yuhina nest had at least 2 color patterns. Obviously, a different female was responsible for each pattern.

Cooperative breeding among birds has been known for decades, but one dominant female typically lays all the eggs in those nests and non-breeding “helpers” assist in feeding the young.

On the contrary, several socially monogamous pairs of unrelated Taiwan Yuhinas, residents of Taiwan’s central highlands, form nesting “coalitions.” Several unrelated pairs lay their eggs in a communal nest and everybody pitches in to feed and defend the young.

Read more – http://goo.gl/AQzNJJ
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The Eurasian Magpie, one of the world’s smartest animals, uses iridescent feathers like designer clothes to convey status, welcome or hostility. http://goo.gl/8D9ZO9

Found throughout Europe, Asia and parts of northern Africa, non-migratory magpie pairs may tolerate immature magpies wandering through their territories. Of course, their own young may stay.

However, mature interlopers must be dressed down.

Magpies use precisely angled flicks of iridescent, sun-lit tail feathers to direct "get out" messages to squatters and competitors.

Read more – http://goo.gl/8D9ZO9
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Physicists have found that high-tech “photonic crystals” give Peacock feathers their beautiful green, blue, yellow and brown hues. https://goo.gl/JL9RFq

Ornithologists who a few decades ago couldn’t have imagined what looks like machine-made crystals in feathers now must figure out how birds got so weird.

Given their flamboyance, it’s no surprise that Peacocks are central to this evolutionary mystery. Obviously, a Peacock’s “feather eyes” don’t help him forage for food or avoid predators. Female preferences for them must have played a key role. In some cases, female preferences for ever-more-flamboyant males can result in a “runaway” selection process that rewards males with the longest tails or reddest feathers. That race to please would explain male Birds-of-paradise, manakins and other species in which females make or break a males chances with a nod of approval.

Darwin said just thinking of colorful birds’ feathers gave him headaches. Natural selection couldn’t explain them. He proposed a separate theory of sexual selection, which has been modified and deepened by modern evolutionary biologists. Aside from all the iridescent male plumage, the real mysteries of avian sexual selection undoubtedly involve female preferences and choices.

Read more – https://goo.gl/JL9RFq
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Birders from around the world travel to Asia to see the striking, long-tailed male Lady Amherst’s Pheasant. The brown, shorter-tailed females also are highly prized by birdwatchers. https://goo.gl/HxoWQv

Named after a countess, Lady Amherst’s Pheasants are found in the dense forests and bamboo thickets of Tibet, southwestern China and extreme northern Myanmar.

Each polygamous male does his best in March and April to seduce 2 to 3 females to mate with him and nest in his territory. Flashing their red crests and preened yellow, red, blue and metallic green body feathers, males perform elaborate, repeated displays in small open areas of dense forest. They raise their incredible white and black capes in one final, spectacular bid to impress the ladies.

Read More – https://goo.gl/HxoWQv
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A male Temminck’s Tragopan's courtship display is a colorful, vibrating multimedia triumph of art and avian lust.

It begins demurely as he peers shyly from behind a rock. Is the less colorful female interested?

He ducks out of view, inflates his flamboyant blue and red throat lappet and raises up.

“Wow!” she must be saying to herself.

The shy Romeo’s urges begin to overtake him. His throat lappet is a glowing shield of light blue dots on a dark-blue ultraviolet background framed by red. His display may add to his own ardor.

As the excitement builds toward a crescendo, his tail feathers spread into a fan. Muscles in his fleshy blue-green horns stiffen and transforms him into a Thor-like pheasant in full. Reproductive imperatives quickly trump any remaining shyness.

Read more – https://goo.gl/sRBhSL
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The Malabar Whistling-thrush uses UV-reflecting feathers and high-pitched whistles to be seen and heard in India’s lush and noisy forests.

The role of ambient acoustics in the evolution of bird song makes the whistling-thrush an important test-species for researchers. Another bird that nests along noisy streams farther east in Asia, the Rufous-faced Warbler, produces even higher pitched songs in the ultrasonic range beyond the audible range of humans.

Male Budgerigars and other parrot species use fluorescent plumage adjacent to UV-reflecting feathers to create highly contrasting colors that we can’t see.

Read more – https://goo.gl/1L6Y4G
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