OCR Text |
Show 1875.] MR. W. H. HUDSON ON THE HABITS OF HERONS. 625 adduced ; for whenever naturalists who have the opportunity take pains to investigate the matter, they will find the so-called fable simple fact-also that some excessively irritable individuals do not require to be surrounded by fire, but will sting themselves to death when merely teased with a stick. The argument I have used is weak enough ; but until the contrary is conclusively shown, it is reasonable to assume that the clammy patches are of some advantage to the Heron. I have not observed Herons fishing by night very closely; but there is one fact inclines me to believe it probable that some species might possess the light-emitting power in question. I am satisfied that the Ardea cocoi possesses as keen a vision by day as any feathered creature, Raptores excepted : the streams on the level pampas are so muddy that a fish two inches below the surface is invisible to the human eye ; yet in these thick waters the Herons fish by night and by day. If the eye is adapted to see so well in the day, how can it see so well at night, and under such unfavourable circumstances, without some such extraneous aid to vision as the attributed luminosity ? Herons, of all birds, fly the slowest; but though incapable of progressing rapidly when moving directly forward, when pursued by a Raptor tbe Heron performs with marvellous ease and grace an aerial feat unequalled by any other bird, viz. that of rising vertically to an amazing height in tbe air. The marvellous ease and celerity with which the pursued ascends until it becomes a mere speck in the blue zenith, the hurried zigzag flight of the pursuer, rising every minute above its prey, only to be left below again by a single flap of the Heron's wings, forms a sight of such grace, beauty, and power that the mind of the beholder is filled with delight and astonishment. I believe these displays are unfrequent; for I have spent many years in regions abounding in Hawks and Herons, and have very rarely seen a Heron attacked. When the enemy comes to close quarters, the Heron instinctively throws itself belly up to repel the assault with its long crooked cutting claws. All Raptorial species possess a similar habit; and the analogous correlation of habit and structure in genera otherwise so widely separated is very curious. The Falcon uses its feet to strike, lacerate, and grasp its prey ; the Heron to anchor itself firmly to its perch ; but for weapons of defence they are equally well adapted, and are used in precisely the same manner. The Heron, with its great length of neck and legs, its lean unballasted body, large wings and superabundance of plumage, is the least suited of birds to perch high ; but the structure of the feet renders it perfectly safe for it to do so. Thus the Heron is enabled to sit on a smooth enamelled rush, or on the summit of a tree, and doze securely in a wind that, were its feet formed like those of other waders, would blow it away like a bundle of dead feathers. In the Variegated Heron (Ardetta involucris), the least of the tribe, the perching-faculty probably attains its greatest perfection, and is combined with locomotion in a unique and wonderful manner. 40* |