According to The Swiss Family Robinson, how do you distinguish a male ostrich from a female ostrich?
The characters in this novel have been stranded on a seemingly uncharted island in the Pacific Ocean, near Southeast Asia. The island was evidently connected to the mainland at some point, because the remarkable diversity of life is almost unbelievable; species exist in close proximity which are found together nowhere else. One of these is the ostrich, which is native to Africa; the presence of this species thousands of miles away requires some stretching of the imagination.
The ostriches are distinguished by their coloration, which is described in Chapters 12 and 13; the males are a dark, glossy black, with the exception of the plumes at the tips of the wings and tail, which are white. The females, in contrast, are uniformly ash-gray or brown, and the effect is "not so handsome" as the males. It also seems that there are typically several females accompanying each male.