The male African Emerald Cuckoo may be the most brilliantly iridescent, shimmering green bird in the world.
By Rex Graham
The much less flamboyant female cuckoos are brood parasites of other birds, a reproductive strategy shared with 1 percent of all bird species, but these females are among the most aggressive of them all.
The females are camouflaged with brown and barred green and white feathers. Hiding in the dense canopy, they carry hard eggs for a day before laying them in unattended nests of bulbuls, warblers, sunbirds, weavers, bee-eaters, shrikes and other songbirds. However, even the occupied nests are fair game.
They will not only chase a bulbul, weaver or other host bird off its nest, but also eject the hosts’ eggs, leaving only her eggs behind. If the host lays more eggs, the cuckoo chick will try to push the foster mother’s eggs or chicks out of the nest.
Male African Emerald Cuckoo Color Patterns
A microscopic-structure and light-scattering study of their green feathers revealed a herringbone zig-zag, milli-scale structure in the barbules. By slightly shifting their position on a branch in relation to the sun, males can direct eye-catching patterns of high and low reflectance.
“Rather than displaying dramatic colour change, C. cupreus shimmers idiosyncratically when incident light and view directions vary,” wrote three Cornell University biologists in the journal Interface.
The scientists said the phenomenal shimmering green patterns seen even in the lab also may be manipulated by males during courtship displays.
I believe that the more that people spend watching, studying, enjoying and photographing African Emerald Cuckoos, the better for the species, all birds, all wildlife and all humans.