or pattern, so precious in the eyes of the systematist, he sees a bird and recognises it. He says that it is a chaffinch, a lark, or a sparrow; but how does he know? Shape, size, manner of flight, or maybe note, is the reply. Yes, but there is something more; something definite yet indefinable, something which instantly registers identity in the brain, though how or what is seen remains unspecified. It is its jizz.
That mental picture recorded through the eye is accurate in proportion to our familiarity with the species; the more familiar we are the less we note except the jizz. The passing curlew may have a long curved bill, a pale lower back, a strong distinctive flight; we knew these characters were present, but we did not actually see them; we saw a curlew. Curlew flashed into the brain without pause for mental analysis, for we noted the jizz. I am often asked the question which the Irishman was asked; I know of no better answer than his.
Personal experience has proved that a skin, a cabinet skin, may be more difficult to recognise than a living bird. In the skin we see certain patches of colour, markings, or patterns with which we are unfamiliar on the bird in the field. They are described in the textbooks it is true, but they are not the points which catch the eye when the bird is alive. In addition all the pose, attitude, and habit-character is lost when bird becomes specimen. Its jizz is gone. The systematist, used to handling these specimens, contends that identification by impression is less sure than by study of detail, which is in the main true, but then, even if an error is made, the bird is still alive! That to the field naturalist as well as the humanitarian is an important point.
How often we hear disputes as to the value of the drawing or the photograph as the more satisfactory portrait of the bird; how futile is much of this discussion!
