Great Argus

Argusianus argus. Also Argus pheasant. Schönbrunn Zoo. 1932.

Its magnificent plumage makes the Great Argus a popular but challenging aviary bird. This cock from Schönbrunn Zoo was particularly dramatically mounted.

DARWIN'S DILEMMA
The extremely shy Great Argus lives in the lowland rainforests of East Asia; growing up to two meters in length, they are among the largest of the pheasant species. The marked difference between the sexes is striking: while the hens are an inconspicuous brown, the cocks have greatly elongated lesser quill feathers decorated with large, radially arranged eye spots that are accentuated with shading and iridescence. In the courtship display, the cock spreads its wings like a fan and raises its tail feathers to impress the hen.
With its magnificent plumage the Great Argus has always attracted attention – not just from his hens. The lesser quill feathers were something of a headache to no less than Charles Darwin in about 1870 because they did not seem to fit into his theory of evolution. What, Darwin wondered, was the purpose of this exuberant beauty in the animal kingdom if it was not functional? After all, the elongated quill feathers mean that the male Great Argus is even worse at flying than any other galliforme. From the cock shown here starting his courtship ritual, we can however deduce that in this case sexual selection had become a driver of evolution.
In 1871 a single feather was found in the luggage of a fashion designer that could not be ascribed to any known pheasant species; naturalist John Wood subsequently created a new species of Great Argus and called it the double-banded Argus. Although no similar feathers have ever been found, since then the double-banded Argus has appeared in the Red List of the International Union for Conservation of Nature as an extinct species.