The male Superb Bird of Paradise is a master shapeshifter. In the throes of his courtship dance, he ceases to look anything like a bird, becoming instead a hopping, snapping, geometric abstraction; a psychedelic smiley face. It’s one of the most bizarre and enthralling displays in the entire animal kingdom.
Hidden in the almost impenetrable mountainous rainforest on the Austalasian island of New Guinea, the 41 species of birds of paradise are some of the most resplendent birds in the world. That is – the males are. They mate promiscuously and competition for female attention is fierce; being a flashy fella pays.
He snaps his tail feathers together rhythmically, hopping and shifting whenever the female moves
The superb bird of paradise calls to females from his display branch. When one alights, he erects an iridescent blue-green breast shield and raises a cape of velvety black feathers that lay across his back, into an ovoid shape around his head. For the final touch, he lifts his beak so that it bisects the iridescent feathers at his crown, giving the illusion of a pair of shimmering eyes.
The female, by comparison, is conservatively dressed in muted greys and browns – evolutionary adaptations that help her blend into the background vegetation and avoid predators. She appears completely mesmerised by the male’s performance. He snaps his tail feathers together rhythmically, hopping and shifting whenever the female moves, in order to keep facing her squarely and maintain his artful illusion.
Precisely what the female uses to choose between mates is something of a mystery. “We don’t know much about female physiology when observing displays,” explains evolutionary biologist Edwin Scholes who has spent years tracking and documenting the birds of paradise. What we do know is that she is extremely picky, and if she likes what she sees the male will get chance to mate pass on his dancing dandy genes to a new generation.
Ribbon-tailed astrapia (Astraoia meyeri)
A compelling example of the power of female choice, the male ribbon-tailed astrapia – another native of New Guinea – grows a bothersome 3-foot-long pair of tail feathers in the name of catching the ladies’ attention.
The feathers are the longest in relation to body size of any bird. They are over three times the length of the male’s body and offer him zero survival advantage. They don’t keep him warm, they hinder his flight, and they can even get tangled in tree branches while he’s foraging for food. So what gives?
The feathers are purely a product of sexual selection, a theory proposed by Charles Darwin to explain the origins of beauty in nature. For years, Darwin struggled to understand how flamboyant ornaments like the peacock’s tail could fit within his theory of natural selection – or “survival of the fittest” – when they so obviously had survival costs such as making the bird more visible to predators and hampering his flight.
Finally, Darwin hit upon the notion that females’ decisions about which male to mate with cause elaborate display traits to evolve. Some traits, like extravagant plumage or complicated dance routines, are energetically costly to the male and signal corresponding good health and quality genes to the female. Others seem to be simply aesthetic whims.
Either way, when a female chooses a mate with a showy trait, her offspring inherit both the trait and the preference. This reinforces and exaggerates the pattern in future generations, which is how the astrapia’s tail got to be so ridiculously long.
Satyr tragopan (Tragopan satyra)
Humans may joke about getting the horn, but the male satyr tragopan actually grows a pair. They’re electric blue, inflatable, and form a matching set with the bird’s brightly patterned, retractable, bib-like throat lappet. The male brandishes this wacky trio of now-you-see-them-now-you-don’t ornaments during a spectacular courtship display that is rooted heavily in the principle of ‘shock and awe’.
Satyr tragopans – considered the most beautiful pheasants in the world – live in dense rhododendron thickets within the subalpine forests of the central Himalayas. During breeding season, the male conceals himself behind a rock or fallen log, where he waits for a passing female. When a potential mate wanders into view, he ambushes her.
The male will vault the obstacle and attempt to copulate
Twitching his head, he gradually exposes and inflates his fleshy lappet, and erects and waggles his horns. He beats his wings rhythmically, in synchrony with a series of vocal clicks, before rising to his full height, fanning his tail, stretching his wings downwards, and fluffing his crimson-coloured feathers to their fullest. If the stunned female sticks around until the end of the show, the male will vault the obstacle and attempt to copulate.
This absurd looking specimen is found in humid mountain forests on the Pacific slopes of the Colombian and Ecuadorian Andes. In males, the wattle the bird is named for – a floppy, feather-covered rod that hangs from its chest – can measure up to 35 centimetres, almost as long as the entire bird. On his head, he sports large crest of fine hair-like feathers, earning him the ‘umbrella’ portion of his name.
Excited males gather in the high branches to display their wares to females, which – at about half the size of males and almost wattle-free – look like large crows. The courtship routine begins with the male unfurling his wattle to its full length, about three times longer than he holds it in flight. He splays its feathers so that it resembles a feather duster, and flares his umbrella until it curls over the top of his bill.
Once his ornaments are ready, he spreads his legs and leans forwards, swinging his wattle and pumping his head up and down as he gulps air into specialised sacs in his throat. Finally, the usually silent bird opens his bill and lets fly a single low-frequency fog-horn-like cry that can be heard up to quarter of a mile away.
Three-wattled bellbird (Procnias tricarunculatus)
An even more accomplished loudmouth, the three-wattled bellbird has one of the most arresting calls in the avian world. The male’s signature sexy “come hither” is a harsh, metallic, and booming “Bonk” that can be heard over half a mile away. It may seem rather objectionable, then, that he hurls this striking call directly into the ears of potential mates.
Ranging from eastern Honduras to western Panama, three-wattled bellbirds are extremely vociferous. They call for over 80% of daylight hours, for over nine months of the year. Throughout this time, males advertise and Bonk from exposed perches above the forest canopy to establish their territory.
Good job he Bonks all the livelong day
During the breeding season, they scope out a “visiting perch” to lure potential mates to, just beneath the canopy. They are curiously particular about the characteristics of this broken-off dead branch – having exacting specifications for its diameter, exposure, and the angle it grows at.
When a female lands to inspect, the male performs flight displays and silently shakes his wattles, which look like a beak full of flapping leeches. He edges her to the end of his branch until she can barely keep a foothold, leans out over her, heaves his chest and opens wide his cavernous black mouth. Finally, he puts his beak to her ear and issues his almighty Bonk.
If that last pair of noisemakers seemed a little, well, abrasive, meet the club-winged manakin. This tiny resident of the Andean cloud forests is the only known species whose male serenades females with violin-like sounds, which he creates using a pair of specially adapted wing feathers.
To make his wings sing, the male holds them aloft over his back and vibrates them more than 100 times per second – twice as fast as a hummingbird. On each wing, the tip of a unique, club-shaped feather rubs against a second modified feather that has a series of ridges along its spine.
The hollow, ridged feather acts as a resonating chamber, producing a sustained high pitched tonal sound. Nine “normal” feathers connected to the adapted pair by a ligament vibrate in harmony and amplify the volume of the sound. Similar mechanical “sonations” are made by crickets, which rub their wings together to produce singing sounds.
In 2012, researchers discovered that the male club-winged manakin’s ulna – the wing bone that supports the resonating feathers – is structurally different to other bird bones. It is solid rather than hollow, and about three times more voluminous than it is in other birds of the same size class.
Scientists aren’t yet certain whether this skeletal difference exists to enhance the wing’s acoustics, resist the unusual forces placed on it during sound production, or simply to heft around the larger musical feathers the rest of the time. Nevertheless, the fact that the mating preferences of female manakins have caused males to develop heavier, more ecologically costly bones emphasises how powerful an evolutionary driver sexual selection can be.
Superb lyrebird (Menura novaehollandiae)
The songbird to end all songbirds, the superb lyrebird is a shy, ground-dwelling pheasant-sized bird that lives in the dense forests of southeastern Australia. The male carries a delicate tail of lacy white plumes bordered by a pair of elegantly curved feathers, which together resemble a lyre – an Ancient Grecian harp.
But his real claim to fame is his virtuosic vocal repertoire.
Breeding occurs in winter, when males prepare raised display mounds of scratched earth. To entice females into plumage-viewing range, the lyrebird sings the most elaborate and complex song he can muster, by copying the calls of all the other creatures in the forest and mixing them in with his own.
This grand master of mimicry can convincingly rattle off the calls of up to 20 other species in a five-minute window, and has even been known to steal more unnatural sounds for his show, including camera shutters, chain saws and car alarms. Ornithologists think that female lyrebirds judge potential mates on both mimetic accuracy and versatility.
During the courtship display, the male emphasises his long extravagant tail by flipping it over his head and fanning it across his back. In 2013, researchers discovered the male lyrebird has one final trick up his sleeve: coordinating choreographed dance steps with specific songs.
Dark-eyed junco (Junco hyemalis)
For more than a century, scientists roundly dismissed the idea that birds might have a sense of smell. But for dark-eyed juncos, a type of small grey North American sparrow, olfaction is real – and it’s central to their reproductive success.
Birds’ preen glands are located near their tails. They use their beaks to spread oils secreted by the glands on their feathers, to keep them in good condition. But a 2012 study uncovered evidence that in dark-eyed juncos, those oils serve another function: chemical signallers for sexual selection.
Male birds whose odour was more “male like” and female birds whose odour was more “female like” at the start of the breeding season were more successful at attracting mates and had more chicks survive and become fledglings. For the junco, smell was a stronger driver of mate choice than visual cues like plumage or body size. The authors of the study postulated that juncos’ preen oil carries messages about the birds’ breeding condition, hormone levels, and overall health.
Interestingly, females also used scent to determine which male actually got to help raise her hatchlings – and at this point, they favoured more "female" smelling birds.
Blue manakin (Chiroxiphia caudate)
For most male animals looking to mate, keeping away the competition is a top priority. Not so for the blue manakin, which actively cooperates with other males to woo females in “leks” – communal, competitive display spaces that remove the burden of mate-seeking travel from the female.
Lek mating systems where males advertise in sight or hearing range of one another are fairly common in birds. But the blue manakin – a small, brightly coloured bird that lives in humid forested lowlands from northeast Argentina to southeast Brazil – takes the idea to the next level, by engaging in synchronised group performances.
Participating males gather in a line at the display stage – a bare horizontal branch they have previously stripped of leaves and shoots. When a female lands on the limb, the nearest male flutters in her face, in a one-second show of sound, colour and aerobatics. When he’s finished, he joins the end of the line, and the next bird in line repeats his display.
The frenzied cycling of suitors continues for several minutes, allowing the female to compare the males’ physiques, coordination, and motor skills. Cooperative to the end, the hopeful candidates line up patiently at the close of the display to await her selection.
Satin bowerbird (Ptilonorhynchus violaceus)
Bowerbirds are the ultimate Casanovas, and pretty impressive architects to boot. Males of this promiscuous Australian family build intricate ground structures called bowers and decorate them lavishly with carefully selected, brightly coloured objects specific to the particular male’s tastes.
The satin bowerbird, for instance, is especially fond of blue. He embellishes his basic bower – a dense pair of parallel walls made of upright twigs – with a plethora of collected ornaments like blue parrot feathers, purple berries and blossoms, greyish snail shells, and man-made trinkets made of blue glass, paper and plastic. All of which perfectly complement his blue-sheened black feathers and deep blue eyes.
Female satin bowerbirds inspect the bowers of many males before selecting a mate, resting just within the safety of the bower’s walls while the male displays outside it. Brandishing one of his decorations in his beak, the male performs a series of dance-like movements, and utters a catalogue of chirps and clicks. If the female deems him worthy, she will remain in the bower, crouching and raising her tail to invite him to copulate.
Bowers serve exclusively as sex dens, and not as nests. In fact, like all the birds on this list (except dark-eyed juncos), the male satin bowerbird plays no part in nest building or chick-rearing at all. So little time, so many females to impress…