234



M. Hachisuka—The Mutant Pheasant



of these Peafowl and G-olden Pheasant are quite outside the human

control. This phenomena—what I term mutation—and its nature

is quite different from the various colour phases of Guinea Fowls

and Budgerigars, which are mere albinism or melanism of birds

sporadically occurring among wild and cage birds and disappears

quickly after a few generations unless artificial control is enforced.


My Pheasant is a parallel example of the Peafowl and Golden

Pheasant just referred to, and we are all aware of the co-existence of

two species of Pheasant, colchicus and tenehrosus, in our woods. It is

like the Tree and House Sparrow, or many allied species of Warblers

breeding in this country in more or less the same type of surroundings.


It was one day during the winter when I happened to be looking

round the poultry shops in Cambridge that I came across a Grouse-

like looking Pheasant. After taking it home and carefully dissecting

it, it proved to be an adult female, but I could not identify to what

species it belonged. I then showed the specimen to Lord Kothschild

who, much to my surprise, told me he was familiar with this type of

bird as coming from Norfolk as early as about 1880. He then brought

to London a male specimen of this bird and after careful study I

subsequently described it at the British Ornithologists’ Club as a

mutant tenehrosus. It was afterwards figured in UOiseau in France

and in Tori in Japan.


This was the first time a mutant species was described as it should

be and all other descriptions of mutants are misleadingly and

merely described as sub-species, species, or hybrids. In order to prove

that tenehrosus is of mutational origin I decided to undertake breeding

experiments and an ornithological friend as well as the Zoological

Society kindly offered me a good stock which I took back with me to

Japan to be bred for several generations. While these experiments

were being carried out tenehrosus suddenly became common in England

and was brought to the notice of several people. At the same time

tenehrosus —being dark in coloration—made considerable confusion,

as it was thought to be the hybrid between colchicus and versicolor.

Most of us are not familiar with the authentic hybrid of the above two

species but vaguely remember that the cross in question is a darker

bird than the common English Pheasant.



