There is another point which should not be overlooked. It has after all become a mere fiction to say that _all_ places are occupied. Nature's nice order has been destroyed, and her kingdom thrown into the utmost confusion; our action tends to maintain the disorderly condition, while she is perpetually working against us to re-establish order. When she multiplies some common, little-regarded species to occupy a space left vacant by an artificially exterminated kind, the species called in as a mere stop-gap, as it were, is one not specially adapted in structure and instincts to a particular mode of life, and consequently cannot fully and effectually occupy the ground into which it has been permitted to enter. To speak in metaphor, it enters merely as a caretaker or ignorant and improvident steward in the absence of the rightful owner. Again, some of our ornamental species, which are fast diminishing, are fitted from their peculiar structure and life habits to occupy places in nature which no other kinds, however plastic they may be, can even partially fill. The wryneck and the woodpecker may be mentioned; and a still better instance is afforded by the small, gem-like kingfisher--the only British bird which can properly be described as gem-like. When the goldfinch goes--and we know that he is going rapidly--other coarser fringilline birds, without the melody, brightness, and charm of the goldfinch--sparrow and bunting--come in, and in some rough fashion supply its place; but when the kingfisher disappears an important place is left absolutely vacant, for in this case there is no coarser bird of homely plumage with the fishing instinct to seize upon it. Here, then, is an excellent opportunity for an experiment. In the temperate regions of the earth there are many fine kingfishers to select from; some are resident in countries colder than England, and are consequently very hardy; and in some cases the rivers and streams they frequent are exceedingly poor in fish. Some of them are very beautiful, and they vary in size from birds no larger than a sparrow to others as large as a pigeon.