Today is Sunday, and that means we have a themed bird post from John Avise. Today’s theme is color, or lack thereof. John’s notes are indented, and you can enlarge his photos by clicking on them.
All-Black or All-White Birds
About two months ago, PCC(E) showed some of my photos of avian species with plumages patterned in BOTH black and white (see “Black-and-White Birds in Color”). But the feathers of many other birds are basically either all-white or all-black. Many of these birds with colorless feathers nonetheless have bright colors on non-feathered body parts (such as eyes, bills, legs or feet). These species raise many questions such as: (a) What (if any) is the adaptive significance of a uniformly dark or light plumage?; (b) Why are so many such species among the most common birds in their respective habitats?; (c) Is sexual selection responsible for the color-laden adornments?; and (d) Are brightly colored bills, eyes, legs, or feet disproportionately found in avian species whose plumages are all-white or all-black? I don’t have the answers to such questions, but the scientific literature probably addresses some of them. Perhaps readers can chime in with hypotheses or evidence. But my task here is merely to share photos of several North American birds that have nearly all-white or all-black plumages. I took these pictures in Southern California or Florida.
Great Egret, Ardea alba, with yellow bill and iris:
Snowy Egret, Egretta thula, with yellow feet, iris, and facial patch:
Cattle Egret, Bubulcus ibis, with yellow bill and iris:
Little Blue Heron, Egretta caerulea, juvenile with bicolored bill:
Snow Goose, Chen caerulescens, with pink bill:
American White Pelican, Pelecanus erythrorhynchos, with yellow gular pouch:
Magnificent Frigatebird, Fregata magnificens, with red gular pouch:
Common Raven, Corvus corax:
American Crow, Corvus brachyrhynchus:
Brewer’s Blackbird, Euphagus cyanocephalus, with white iris:
Great-tailed Grackle, Quiscalus mexicanus, with white iris:
Phainopepla, Phainopepla nitens, with bright red iris:
American Coot, Fulica americana, with white bill and red iris:
Black Oystercatcher, Haematopus bachmani, with bright red biil and yellow eyes.
the images of the crow and the raven appear to be switched
not 100% sure, I am not a birder
I always enjoy the Avise bird series
I agree. I believe the size of the bill is one of the clues.
Yes, you’re absolutely right. Thanks for pointing this out this error. These two photos somehow got reversed during the submission and posting process.
I’ll switch them around; thanks.
Great pictures, as always!
Fascinating photos — thanks!
The paradigms of black and WHITE kind of drive us … nuts?
Conundrums without end — or easy explications!
Invitations to exploration!
Fun & fascination for the inquiring mind!
Here in the SE corner of AZ, we have the Chihuahuan Raven, Corvus cryptoleucus (Couch 1854).
It’s also known as the WHITE-Necked Raven — which has got to be a puzzler for casual observers.
The species name denotes: crypto = hidden + leucus = WHITE”, I think [my emphases].
You can see the snow-white lower portions of the neck feathers when the wind ruffles the feathers.
Or, you can examine them at your leisure on a dead bird — as I did about 50 years ago.
What is the adaptive function of those snowy under-feathers?
Perhaps the white allows a greater absorption of sunlight for vitamin D production?
This blackness & whiteness perfuse our minds, & I think some of it comes from our DNA.
And it plays all-too-readily into cultural & racial stereotypes.
Is there, somewhere on earth, a white raven species with black under-feathers on its neck?
Merci et bravo!
Simple, interesting theme – nice!
YES! More corvids …oh… and insects!!!
Excellent. Crows rule!
D.A.
NYC
Beautiful photos, John, thanks!