COMPULSIVE OBSESSION

We often see small birds harassing larger ones in flight. It occurs between any number of species, and ravens pestering hawks is most common. As I biked along an embankment one day, a red-tailed hawk slowly passed me in the breeze rising there, and behind it a raven repeatedly nipping at the hawk’s tail. The hawk would flinch at each assault, but always glide on in stately fashion. Such episodes are so common we usually dismiss them and look away, but these guys were right there beside me so I kept watching – and sure enough saw something unexpected. When that embankment ended the two birds smoothly formed up line abreast and glided off wingtip to wingtip, looking more like partners in crime than born rivals. Could any zoologist (or strained anthropomorphism) explain such social dynamics between competing species? In mortal conflict, a raven’s wacky precocity would be no match for the deadly prowess of any large raptor. So why should such a fierce killer tolerate the nuisance? What evolutionary advantage is there in not casually dispatching the raven at will? Maybe hawks dislike eating crow as much as people do.

Before you answer that here’s another data point.  I was sitting on a long ridgetop beneath a migratory flyway for raptors where a clan of ravens (properly called a conspiracy) were soaring in the west wind, chasing each other, babbling in their endless array of voices and providing splendid distraction from a hazy gray sunset. Every few minutes a solitary hawk would glide silently overhead on its migration from Quebec to wintering grounds in Dixie. Most were cruising by well above the ridge never flapping a wing, ignoring and ignored by those ravens cavorting downstairs, but when one red-tail came through below the crest they jumped it. Harassment from a whole group the hawk had to take seriously. It shifted down and powered up to climb fast and quickly get away. But as the ravens returned to their idyll squawking in presumed triumph, the escapee headed quietly... back north.Very soon two red-tails arrived. One orbited overhead, providing ominous cover while the other dove down to put that impudent conspiracy in its place. One after another it singled out each raven for humiliation, luring them onto its tail and hurtling so close to rocks that pursuers would pull away shrieking with alarm. After outflying every individual separately without once engaging any of them frontally, the majestic hawk circled up to its waiting ally and glided off for the winter.Here too we see no lethal intent by the raptor.  It seemed from my human perspective content to simply preserve its honor, settle the score. Who knows what a feral bird really thinks, if anything, but if ravens, intellects of the class, are compelled to tease their fearsome cousin, why should the master at arms not demand at least a minimal respect? Is this saying too much? Does it matter? Here as everywhere, Nature remains indifferent to our opinions. She simply is. Here's a theory. Like coyotes, primates and other four-limbed folk, ravens are curious and playful and always looking around for something interesting to do. The raptor meanwhile, knowing small prey scamper after birds' shadows pass, watches telscopically from overhead as its low rent inlaws stir all corners of the pot, exposing the best delicacies for its own palate. Just a theory. Got a better one? Nor is ravens’ peskiness limited to getting the best of other creatures. In town once I saw several over a vacant lot, circling an empty shopping bag lofted by a thermal. They took turns rushing in to peck at it – presumably for the same reason I've done the very same in gliders. Then just because it could, one individual snared the bag’s handle in its beak. Immediately the bag inflated and billowed behind, a drogue chute larger than the bird itself. Sometimes size does matter. Unwilling to capitulate, the raven held stubbornly to its prize for a full circle, falling far below its mates.It soon tired of this, naturally, but then, well after dropping the bag it still could not resist diving back for one last retaliatory peck.Why?  Why not!