Birds
Club-winged Manakin
Machaeropterus deliciosus · also called club-winged manakin
The club-winged manakin makes music the way a cricket does — not with its voice, but by rubbing body parts together. The male shivers his wings over his back a hundred times a second, raking a pick-shaped feather across a ridged one, and specially thickened feather shafts turn the clicks into a pure violin note.
Overview
Club-winged manakins live in humid foothill and montane rainforest on the Pacific slope of the Andes in western Colombia and northwestern Ecuador, roughly 700–1,600 m. They are tiny (11–13 cm), the male brick-red with a yellow crown and black-and-white wings, the female plain olive. They eat mostly small fruit.
The wing song
Displaying, the male flips his wings over his back and shivers them, so a stiff, bent feather tip rakes across a ridged neighbour — a file-and-scraper, like a cricket. The wings oscillate ~100 times a second. Several feathers have hollow, swollen, or twisted shafts that resonate near 1,500 Hz, smoothing the rapid clicks into one sustained musical tone — a “tick-tick-ting.”
Bones no flier should have
To transmit the vibration, the wing bones are unusually thick and solid instead of hollow. Strikingly, the females have the same dense bones despite gaining nothing from them — an apparent aerodynamic cost dragged along by sexual selection on the males.
Status
The club-winged manakin is Least Concern, locally common, but tied to the heavily cleared Chocó and western Andean forests.
Club-winged Manakin: common questions
How does a bird sing with its wings?
The club-winged manakin uses stridulation, the same mechanism a cricket or grasshopper uses to chirp — dragging a scraper across a file of ridges. The male raises both wings vertically over his back and shivers them from side to side extremely fast. On each wing, one feather has a stiff, club-shaped, bent tip that acts as a pick, and the feather next to it has a shaft with a series of about seven raised ridges. As the wings sweep back and forth, the pick rakes across the ridges, producing a rapid train of clicks. The wings move back and forth roughly 100 times a second, twice the wingbeat frequency of a hovering hummingbird, so the clicks come far too fast to hear individually.
Why does it sound like a violin instead of a rattle?
Because the manakin's wing feathers are not just a file and scraper, they are also tuned resonators. Several of the feathers involved have shafts (rachises) that are hollow, swollen, flattened, or twisted into a curl, and these vibrate strongly at a particular frequency, around 1,500 hertz. When the rapid clicks from the file-and-pick excite these feathers, the whole feather array rings at that single pitch, smoothing the clicks into one clear, sustained, almost electronic-sounding tone that people transcribe as "tick-tick-ting." High-speed video and laser measurements have shown the feathers resonating exactly as a plucked or bowed string would.
What is strange about the club-winged manakin's bones?
To make wing feathers vibrate hard enough to produce a loud, pure tone, the manakin needs stiff structures to transmit the energy, and its wing bones (the ulna and others) are much thicker and denser, with little or no internal air space, compared with the light, hollow, air-filled bones typical of flying birds. The surprising part is that the females, which do not sing with their wings and gain nothing from the heavy bones, have the same solid-boned wings as the males. This means the trait is not being switched on only in males; the genetic changes affect both sexes, and the females appear to carry a real aerodynamic cost, likely flying less efficiently, purely as a side effect of sexual selection acting on the males. It is a well-cited example of how a sexually selected male trait can drag the whole species along.
Where do club-winged manakins live and are they endangered?
They are restricted to humid foothill and lower montane rainforest on the Pacific-facing slope of the Andes in western Colombia and northwestern Ecuador, roughly between 700 and 1,600 metres elevation, a naturally limited band of habitat. Within that zone they are locally fairly common, and the species is currently listed as Least Concern. However, the Chocó and western Andean forests they depend on are among the more threatened in South America, cleared for agriculture, cattle, logging, and mining, so the manakin's future is tied to how much of that specific mid-elevation forest is protected. Males display at traditional sites (leks) in the forest interior and need mature, structurally complex understorey.