Storks taught glider pioneers how wide wings ride thermals
Ciconiidae storks—twenty species of long-legged, long-billed waders—now alone hold order Ciconiiformes after herons and ibises moved to Pelecaniformes. Drier habitats than herons, bill-clattering at nests, and soaring on thermals define a family whose marabou spans about 3.2 meters.
Storks are built for riding warm air. Heavy birds with broad wings, they soar and glide on thermals rather than flap, saving energy on long migrations. The marabou, with a 3.2-metre wingspan and up to 8 kilograms of weight, ties the Andean condor for the broadest wingspan of any land bird. Ottomar Anschütz's 1884 photographs of storks in flight helped inspire Otto Lilienthal's gliders later that century.
Sizes run from the marabou, 152 centimetres tall, to Abdim's stork at 75 centimetres and 1.3 kilograms. Bills match diets: the generalist Ciconia storks have the plainest ones; saddle-bills and the jabiru carry heavy, slightly upturned bills for fishing in shallows; the adjutants and marabou wield huge daggers for carrion and for fending off other scavengers; and Mycteria storks feel for prey with sensitive, downcurved tips. Storks are often called mute, but they have a reduced syrinx and can make sounds, though they mostly communicate by clattering their bills at the nest. Those nests can be reused for years and grow over 2 metres wide.
Genetic studies moved herons, ibises and their relatives to the Pelecaniformes, leaving the 20 living storks alone in their order. The family was well established by the Oligocene and probably arose 40 to 50 million years ago. Tropical Asia and sub-Saharan Africa hold the most species, eight and six breeders, while the Americas have only three, including the jabiru, the tallest flying bird of the New World.
Not a single stork species has vanished in recorded history, but a review of nearly 1,000 papers found most species poorly studied. The name comes from a root describing their stiff posture, shared with the word stark.
Source: Stork
