Since the progress of civilization in our country has furnished thousands of convenient places for this Swallow to breed in, safe from storms, snakes, or quadrupeds, it has abandoned, with a judgment worthy of remark, its former abodes in the hollows of trees, and taken possession of the chimneys which emit no smoke in the summer season. For this reason, no doubt, it has obtained the name by which it is generally known.
John J Audubon, Birds of America, Plate 158: “American Swift”
Vaux’s swifts (Chaetura vauxi) is a species of swift native to the American Pacific Northwest and South America. Like others in its genus, vaux’s swifts are impressive aerialists, capable of high-precision maneuvers at speeds in excess of 100 km/h. On the other hand, they are frequently described as “small, dark, fast-flying cigars with wings”, which isn’t a particularly majestic characterization.
In the Alphabet District of Portland Oregon (a short walk from NSHipster headquarters, as it were), Chapman Elementary School is host to North America’s largest concentration of Vaux’s swifts.
Every evening, from late summer through October, thousands of swifts can be seen just before sunset as they fly into the school’s old smokestack to roost for the night. At dawn, they emerge once again and continue their migration to Central and South America.
Vaux’s are among the more gregarious species of swifts,
observed to flock in the dozens.
Moving together as a group,
the whirling mass of birds flying in and out of their roost
creates a phantasmal silhouette against the twilight sky .
Among the first computer simulations of this flocking behavior was a program called Boids, created by Craig Reynolds in 1986. It remains one of the most striking examples of emergent behavior, with complex — seemingly chaotic — interactions arising from a small set of simple rules:
- separation: steer to avoid crowding local flockmates
- alignment: steer towards the average heading of local flockmates
- cohesion: steer to move towards the average position (center of mass) of local flockmates
The following simulation is an implementation of Craig Reynold’s “Boids” program, created by Daniel Shiffman using Processing.js. (Click or tap to add a new bird.)
As you gaze upon this computational approximation of flocking swifts, consider, for a moment, the emergent nature of your own behavior.
What separates you from others? How often is your direction more a consequence of your surroundings than a reasoned, conscious choice? And when you are, indeed, making such a decision, how is your choice shaped by the consensus of your peers?
…or don’t. Such philosophical introspection is but a fool’s errand.
