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.