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Posts Tagged ‘escape’

murmuration-1Photo: Daniel Biber, via the Independent
A murmuration of starlings was targeted by a bird of prey and took the form of a giant bird. But contemporary scientists insist “thinking” isn’t involved. 

The natural world never ceases to amaze. Consider the flight of large groups of starlings. You have probably seen some of the YouTube videos. Mark MacNamara wrote about the phenomenon at Nautilus in March.

“Eugene Schieffelin was the eccentric ornithologist who in 1890 shipped 60 starlings from London to New York City and set them free in Central Park. The next year he released 40 more, and today there are maybe 200 million starlings in the United States and Southern Canada. [Starlings] are shrewd flyers, clever mimics, and often unwelcome … displacing woodpeckers and flycatchers, and destroying entire crops of berries and cherries. Not to mention the havoc they cause at many airports.

“Ah, but when they come round in their murmurations on fall afternoons, or in early winter, what magicianry is that, gathering up out of nowhere, arriving in strands or massive clusters, over inlets or forests. You’ll see them fill up neighboring trees and fall into an oily, high-pitched chatter. [The] most subtle spooking will do it, a dog’s bark, the slam of a car door down the street, or nothing at all, and off they go at 50 miles per hour, wheeling around the countryside, sheets and sheets of them, thickening and thinning, blackening and scattering, merging and splitting. …

“The performance is self-organized, cohesive, and perfectly synchronized; and distinguished by elaborate patterns of spirals, spheres, planes, and waves. What causes starlings to perform these displays? …

“Theories have evolved over the last century. In 1931, Edmund Selous, a renowned ornithologist and bird activist [sumised] that birds in a flock must all be ‘thinking’ as one; how else to explain the synchronization except by telepathy. …

“Later theories suggested that murmurations are ways to find food and keep warm. Those theories linger, but in the past 50 years the predominant explanation is predation, particularly the role of raptors, such as hawks and falcons, in triggering escape behaviors that involve particular patterns of grouping. …

“In the mid 1960s, researchers found that murmurating birds, particularly starlings, interact—not always, but often — with six or seven of their closest neighbors, who interact with six or seven of their closest neighbors. In recent years, studies posit that a network with seven neighbors optimizes the trade-off between ‘group cohesion and individual effort.’

One theory among researchers, in the context of predation, is that starlings are ‘managing uncertainty while maintaining consensus.’ …

“In a murmuration, the distance between fellow fliers is based on a set of rules also seen in certain kinds of fish and insects. These rules require birds to draw closer to birds farther away; at the same time, not to get too close to the nearest neighbor; and finally to join in directional flow. Add to these rules the aerodynamic factors in starlings — and the blistering speed at which the birds turn, climb, and dive — and you have a sense of the intricacy of flock synchronization. …

“In 2019, evolutionary biologist Rolf F. Storms at the Groningen Institute for Evolutionary Life Sciences in the Netherlands, led a study on starlings that delved into the rules of murmurations. … The study [found] different patterns of escape by the starlings.

“For example, when a falcon attacked a flock from above — not from the sides or below, and at high speed — the starlings frequently [scatter] in all directions in the sky. … When a falcon attacks starlings at medium speed, allowing it to be detected, warnings spread through the flock, and the birds respond in a ‘wave.’ They turn right and left, zig and zag, creating ‘darkened bands’ that ripple through the flock, confusing the falcon. …

“Grainger Hunt, Senior Scientist Emeritus with the Peregrine Fund’s California Condor and Aplomado Falcon restoration project, underscores the fact that murmurations are emergent. …

” ‘The peregrine does not purpose the shapes and movements of the flock. Nor does any starling. The spectacle of wondrous shapes and movements is an unintended effect. The peregrine is trying to catch a starling, and each starling is trying not to get caught.’ ” More.

Would you agree that humans need to learn from the starlings how to maintain consensus while managing uncertainty? What a concept!

Video: Dylan Winter
A murmuration of starlings.

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