It’s Sunday, ergo we have a batch of themed bird photos from biologist John Avise. Today’s photos are about flocking in formation. The IDs are John’s; click on the photos to enlarge them.
When birds fly in tandem or in groups, they sometimes save energy by slipstreaming in another’s wake, much as do racecar drivers or racing bicyclists. [Trailing birds also benefit by updrafts from the wing-tip vortices of leading birds.] But trailers also need an unobstructed forward view, which motivates them to move a bit to one side or the other of a lead bird. For larger groups in flight, this behavior can morph into beautiful “V-formations”, much like those used by skilled pilots such as the Navy’s Blue Angels.
Incidentally, do you know why one arm of an avian V-formation is often longer than the other? . . . . . . . Answer: it’s because the longer arm has more birds! [ha ha].
American White Pelicans, Pelecanus erythrorhynchos:
More American White Pelicans:
Brown Pelicans, Pelecanus occidentalis:
Cattle Egrets, Bubulcis ibis:
More Cattle Egrets:
Canada Geese, Branta canadensis:
Three Canada Geese:
More Canada Geese:
Double-crested Cormorants, Phalacrocorax auritus:
More Double-crested Cormorants:
White ibis, Endocimus albus:
Snow Geese, Chen caerulescens:
More Snow Geese:
Still more Snow Geese:
White-faced Ibis, Plegadis chihi:
More White-faced Ibis:
Still more White-faced ibis:
Many more White-faced Ibis:
7 thoughts on “Readers’ wildlife photos”
Wonderful! Aeronautical engineers must have learned plenty from observing these exquisitely skilled flyers.
Great photos (and joke!). Probably a stupid question, but is there any advantage in synchronised wing flapping in these formations? Birds seem to be in synchronicity in some photos but not in others.
I don’t know of any advantage (or disadvantage) of synchronized flapping. And I’ve never actually noticed any particular proclivity toward such behavior. Perhaps it might serve to keep birds in a formation going at the same speed (and hence also appropriately spaced from one another).
Thanks – that would make sense.
Beautiful pictures. And thanks for the explanations.
What a lovely set of black-&-white underwing patterns.
Your systematic groupings of photos encourage thoughtfulness.
I often wonder what adaptive signaling is contained in these striking underwing patterns.
Signaling within a species, I mean; but also likely: signaling between species.
#1] CATTLE EGRETS
The 4th photo down — of 6 Cattle Egrets — really got me to wondering.
They have white underwings, but shadows play a mind-tingling game of “What’s-going-on-here” if one stops to wonder.
Like this —> the top bird of the 6 — & also the 5th bird — shows an all-white underwing.
But the other 4 show other patterns, with all-black underwings on 2 birds.
And the other 2 have half-black underwings.
And the 5th photo down — also of Cattle Egrets — continues the idea with 20 birds.
#2] WHITE IBIS
The 11th photo down, of the White Ibis — also shows a striking pattern.
Look at the 4 black “fingers” at the very tips of the very white wings!
It seems to me that that has to be an adaptive feature in the plumage of the bird.
#3] SNOW GEESE
The Snow geese in the 12th photo down also show a distinctive pattern.
These all remind me of a communication-at-a-distance system we humans use.
As in semaphore signaling.
This is especially true during migration over unknown territory.
Both landing & taking off are energy-demanding for birds, & are fraught with peril.
And so is knowing, from a distance, whether to congregate at 1 site or another.
Different water-birds have vastly divergent needs for feeding & night-roosting.
Signals from a flock of 1 species to other flocks of the same species could be adaptive.
And — might these different species be sharing signals between species?
Egrets & ibis & geese all have needs of particular waters.
And so do pelicans & egrets & cormorants.
Some patterns might tell some birds that landing with that congregation is unlikely to be productive.
Thanks for your interesting conjectures. I’ve often wondered why several mostly-white but unrelated species– notably White Pelicans, White Ibis, and Snow Geese– all have black wingtips most evident in flight. I don’t have an answer, and concocting “just-so” stories is always problematic.