The Unfeathered Bird

500 years after Leonardo, the mechanics of bird flight still enthralls.

(Katrina van Grouw)


(Katrina van Grouw)

The sandgrouse’s skeleton is dominated by the large, triangular keel to the breastbone, resembling the sail of a yacht. Although its proportions are accentuated by the birds’ small head and diminutive tarsi and toes, this bone, whose function it is to support the substantial bulk of flight muscles, is the key to sandgrouse success. Strong, fast, and direct flight, sustainable over considerable distances, enables sandgrouse to commute. They can live “out of town,” in arid regions, where the seeds that form their diet are plentiful, free from the competition and risk of predation associated with water-rich areas, by simply making daily trips to waterholes to drink. Each species has its own particular time slot at the water hole. During these flights, sometimes exceeding a hundred miles in a round-trip, they call noisily to one another, attracting birds to join them to gain safety in numbers. Sandgrouse have even been known to out-fly hunting falcons. Pictured at right: Pallas's Sandgrouse.

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