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Show 624 MR. W. H. HUDSON ON THE HABITS OF HERONS. [Nov. 16, condemned by the imperfections of their organs to a perpetual struglge with misery and want. Much as the different species vary in size, from the Ardea cocoi to the diminutive Variegated Heron of Azara (Ardetta involucris), no bigger than a Snipe, there is yet much sameness in their conformation, language, flight, nesting and other habits. They possess a snake-like head and neck, and a sharp taper beak, with which they transfix their prey as with a dart-also the serrate claw about which so much has been said, and which has been regarded as an instance of pure adaptation. A curious circumstance has come under my observation regarding Herons. Birds in poor condition are very much infested with vermin ; whether the vermin are the cause or effect of the poor condition, I do not know ; but such is the fact. Now in this region (the Argentine Republic) Herons are generally very poor, a good-conditioned bird being a very rare exception ; a majority of individuals are much emaciated and infested with intestinal worms ; yet I have never found a bird infested with lice, though the Heron would seem a fit subject for them, and in the course of m y rambles I have picked up many individuals apparently perishing from inanition. I do not wish to insinuate a belief that this immunity from vermin is due to the pectinated claw ; for though the bird does scratch and clean itself with the claw, it could never rid the entire plumage from vermin by this organ, which is as ill adapted for such a purpose as for "giving a firmer hold on its slippery prey." The Spoonbill has also the serration, and is, unlike the Heron, an active vigorous bird, and usually fat; yet it is much troubled with parasites, and I have found birds too weak to fly and literally swarming with them. I merely wish to call tbe attention of ornithologists to the fact that in the region where I have observed Herons, they are exempt in a remarkable degree from external parasites. Much bas also been said about certain patches of dense, clammy, yellowish down under the loose plumage of Herons. These curious appendages may be just as useless to the bird as the tuft of hair on its bosom is to the Turkey-cock ; but there are more probabilities the other way, and it may yet be discovered that they are very necessary to its well-being. Perhaps these clammy feathers contain a secretion fatal to the vermin by which birds of sedentary habits are so much afflicted, and from which Herons appear so strangely free. They may even be the seat of that mysterious phosphorescent light which some one has affirmed emanates from the Heron's bosom when it fishes in the dark, and which serves to attract the fish, or to render them visible to the bird. Naturalists have, I believe, dismissed the subject of this light as a mere fable without any foundation of fact; but real facts regarding habits of animals have not unfrequently been so'treated. Mr. Bartlett's interesting observations on tbe Flamingoes in the Society's Gardens, show that the ancient story of the Pelican feeding its young on its own blood is perhaps only a slightly embellished account of a common habit of the bird. The story of the scorpion "girt by fire" turning its weapon upon itself, may also*be |
