Formation flying helps sanderlings avoid danger
- jjvanm
- Feb 21
- 3 min read
Published February 21, 2026, in the McAllen Monitor
Story and photos by Anita Westervelt, Texas Master Naturalist
We have all seen it. Droves of early morning blackbirds in undulating waves, heading off to feed in fields and beyond. A similar ribbon can be seen in cities as grackles surge from neighborhood trees in synchronized stages to feeding destinations known only to the birds.
On a smaller scale, the beach offers quick diamond-shaped formations as a dozen small birds simultaneously rocket off the wet sand. In a seemingly well-rehearsed maneuver, the birds dip one wing toward the beach, the other skyward, displaying their grey uppers; seconds later, a coordinated roll glints silver as the sun sparkles off their white underparts. Just as quickly, the squadron lands up the beach, to dance again at the edge of the wash and draw of the tide.
The small contingent of shore birds are sanderlings, little grey-and-white sandpipers with stout black bills and black feet.
Sanderlings are known for their fast side-stepping at the edge of incoming waves and then abruptly turning to chase the receding water, as if not wanting to get their feet wet. It is not that at all. As a wave runs off the sand, invertebrates, like sand crabs – sanderlings’ favored prey – are exposed and easy to pluck up. They also race over wet sand, rapidly probing for crustaceans, insects, marine worms and small mollusks.
Sanderlings are seven to eight inches in length. They are long-distance migrants that breed only on High Arctic tundra. During winter, they live on most of the sandy beaches around the world. They migrate northwards from March to June.
We see sanderlings only in their winter plumage, even in summer. Non-breeding sanderlings often stay on their wintering grounds through the summer, retaining their grey and white plumage. Immature birds lack hormonal triggers to change to breeding plumage.
Sanderlings generally go unnoticed by beachcombers because they dart along the beach, working the sand, surreptitiously keeping pace ahead of the interlopers. At the first instant of threat, though, the birds take flight to repeat their aerial evasive maneuvers. Humans, playful dogs, loud noises and aerial predators will cause sanderlings to flee. The peregrine falcon is a particular danger. Large gulls and raptors also prey on the small sanderlings. Their main defense: creative maneuvering of abrupt, coordinated escape flights; the premise being, taking off as a unit makes it difficult for predators to lock onto a single target.
While sanderlings lift off quickly in formation, gaggles of gulls take flight from danger in a chaotic flurry that once airborne, arranges itself as a group circle to land further along the beach.
As for those massive coordinated avian aerial formations, the shifting, zig-zagging and directional changes also are evasive tactics, tagged as the chorus-line hypothesis, a term zoologist Wayne Potts coined in an article published in the journal “Nature.” When one bird senses danger, its neighbors react to the movement in a ripple effect that confuses predators.
He surmised that birds maneuver quickly because they see a movement far down the line and anticipate what to do next, much like dancers in a chorus line.
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Sources helpful in writing this article were www.audubon.org, allaboutbirds.org, and
