AVIARY, called by older writers "volary," a structure in which birds are kept in captivity. While the habit of keeping birds in cages dates from a very remote period, it is probable that structures worthy of being termed aviaries were first used by the ancient Romans, who called them ornithones. These consisted merely of four high walls and a roof, and were lighted with a few small windows, as the birds were considered to pine less if they could not see their free companions outside. Water was introduced by pipes, and conducted in narrow channels, and the birds were fed chiefly upon dried figs, care fully peeled, and chewed into a pulp by persons hired to do this.
The habit of keeping birds in aviaries for the sake of the pleasure they afford their owners and for the observation of their habits is, however, comparatively recent. The beginning of geographical research in the 15th century brought with it the desire to keep and study at home some of the beautiful birds the explorers came across, and hence it became the custom to erect aviaries for their reception. In the i6th century, in the early part of which the canary bird was introduced into Europe, aviaries were not uncommon in gardens of the wealthy, and Bacon refers to them in his essay on gardening (1597). Within recent years the method of keeping birds in large aviaries has received considerable attention.
An aviary may be of almost any size, from the large cage known, from its shape, as the "Crystal Palace aviary," to a struc ture as large as a church ; and the term is sometimes applied to the room of a house with the windows covered with wire netting; but as a rule it is used for outdoor structures, composed princi pally of wire netting supported on a framework of iron or wood work. For quite hardy birds little more than this is necessary, providing that protection is given in the form of growing trees and shrubs, rock-work or rough wooden shelters. For many deli cate species, however, from tropical countries, warmth must be provided during the winter, and thus part at least of an aviary designed for these birds must be a wooden or brick house which can be shut up in cold weather and artificially warmed.
The ideal aviary, probably, is that which is constructed in two parts; viz., a well-built house for shelter in the winter, opening out into a large wire enclosure for use in the summer months. The doors between the two portions may be of wood or glazed. The sheltered portion is best built in brick or stone, as these materials are practically vermin-proof and the temperature in such a build ing is less variable than in a thin wooden structure. The floor should be of concrete or brick, and the house fitted with an effi cient heating apparatus from which the heat is distributed by means of hot-water pipes or some other recognized method. Any arrangement which would permit the escape into the aviary of smoke or noxious fumes is to be strongly condemned. Such a house must be well lighted, preferably by skylights ; but it is a mistake to have the whole roof glazed; at least half should be of wood, covered with slates or tiles. Artificial lighting, though not essential in most cases, is desirable during dull weather and short winter days, and electric light may be installed with great advan tage ; but some method of gradually dimming this is necessary to enable the birds to find their roosting places before the light is completely extinguished. Perches consisting of branches of trees with the bark adhering should be fixed up, and, if small birds are to be kept, bundles of bushy twigs should be securely fixed in corners under the roof.
The outer part, which will principally be used during the sum mer, though it will benefit most birds to be let out for a few hours on mild winter days also, should be as large as possible, and con , structed entirely of wire netting stretched on a framework of wood or iron. If the latter is selected, stout gas-piping is both stronger and more easily fitted together than solid iron rods. If the frame work be of wood, this should be creosoted, preferably under pres sure, or painted with three coats of good lead paint, the latter pre servative also being used if iron is selected. The wire netting used may be of almost any sized mesh, according to the size of birds to be kept, but as a general rule the smallest mesh, such as half or five-eighths of an inch, should be used, as it is practically vermin proof, and allows of birds of any size being kept. Wire netting for aviaries should be of the best quality, and well galvanized.
Provision must be made for the entire exclusion of such vermin as rats, stoats and weasels, which, if they were to gain access, would commit great havoc amongst the birds. The simplest and a very effectual method of doing this is by sinking the wire netting some aft. into the ground all round the aviary, and then turning it outwards for a distance of another foot as shown in fig. i.
The outer part of the aviary should be turfed and planted with evergreen and deciduous shrubs, and be provided with some means of supplying an abundance of pure water for the birds to drink and bathe in; and a gravel patch should not be forgotten.
Perhaps the most useful type of aviary is that built as above described, but with several compartments, and a passage at the back by which any compartment may be visited without the necessity of passing through and disturbing the birds in other compartments. Fig. 2 represents a ground plan of an aviary of this type divided into four compartments, each with an inner house i oft. square, and an outer flight of double that area. The outer flights are intended to be turfed, and planted with shrubs, and the gravel path has a glazed roof above it by which it is kept dry in wet weather. Shallow water-basins are shown, which should be supplied by an underground pipe and a cock which can be turned on from outside the aviary; and they must be connected with a properly laid drain by means of a waste plug and an over flow pipe.
An aviary should always be built with a southern or south-east ern aspect, and, where possible, should be sheltered from the north, north-east and north-west by a belt of fir-trees, high wall or bank, to protect the birds from the biting winds from these quarters.
When parrots of any kind are to be kept, it is useless to try to grow any kind of vegetation except grass, and even this will be demolished unless the aviary is of considerable size. The larger parrots will, in fact, bite to pieces not only living trees but also the woodwork of their abode, and the only really suitable materials for the construction of an aviary for these birds are brick or stone and iron; and the wire netting used must be of the stoutest gauge or it will be torn to pieces by their strong bills.
The feeding of birds in aviaries is, obviously, a matter of the utmost importance, and, in order that they may have what is most suitable, the aviculturist should find out as much as possible of the wild life of the species he wishes to keep, or if little or nothing is known about their mode of living, as is often the case with rare forms, of nearly related species whose habits and food are prob ably much the same, and he should endeavour to provide food as nearly as possible resembling that which would be obtained by the birds when wild. It is often, however, impossible to supply precisely the same food as would be obtained by the birds had they their liberty, but a substitute which suits them well is generally obtainable. The majority of the parrot tribe subsist principally upon various nuts, seed and fruit, while some of the smaller parakeets or paroquets appear to feed almost exclusively upon the seeds of various grasses. Almost all of these are com paratively easy to treat in captivity, the larger ones being fed on maize, sunflower-seed, hemp, dari, oats, canary-seed, nuts, and various ripe fruits, while the grass-parakeets thrive remarkably well on little besides canary-seed and green food, the most suit able of which is grass in flower, chickweed, groundsel and various seed-bearing weeds. But there is another large group of parrots, the Loriidae or brush-tongued parrots, some of the most inter esting and brightly coloured of the tribe, which, when wild, subsist principally upon the pollen and nectar of flowers, notably species of Eucalyptus, the filamented tongues of these parrots being peculiarly adapted for obtaining this. In captivity these birds have been found to live well upon sweetened milk-sop, which is made by pouring boiling milk upon crumbled bread or biscuit. They frequently learn to eat seed like other parrots, but, if fed exclu sively upon this, are apt, especially if deprived of abundance of exercise, to suffer from fits, which are usually fatal. Fruit is also readily eaten by the Tories and lorikeets, and should always be supplied.
The foreign doves and pigeons form a numerous and beautiful group which are mostly hardy and easily kept and bred in cap tivity. They are for the most part grain-feeders and require only small corn and seeds, though the group of fruit-pigeons are fed in captivity upon soft fruits, berries, boiled potato and soaked grain.
The various finches and finch-like birds form an exceedingly large group and comprise perhaps the most popular of foreign aviary birds. The weaver-birds of Africa are mostly hardy and easily kept, their food consisting, for the most part, of canary seed. The males are, as a rule, gorgeously attired in brilliant colours, some having long flowing tail-feathers during the nuptial season, while in the winter their showy dress is replaced by one of sparrow-like sombreness. The grass-finches of Australasia con tain some of the most brilliantly coloured birds, the beautiful grass-finch, Poephila mirabilis, being resplendent in crimson, green, mauve, blue and yellow. Most of these birds build their nests, and many rear their young, successfully in outdoor aviaries, their food consisting of canary and millet seeds, while flowering grasses provide them with an endless source of pleasure and whole some food. The same treatment suits the African waxbills, many of which are extremely beautiful, the crimson-eared waxbill or "cordon-bleu" being one of the most lovely and most frequently imported. These little birds are somewhat delicate, especially when first imported, and during the winter months require arti ficial warmth.
There is a very large group of insectivorous and fruit-eating birds very suitable for aviculture, but their mode of living neces sarily involves considerable care on the part of the aviculturist in the preparation of their food. Many birds are partially insectivo rous, feeding upon insects, when these are plentiful, and upon various seeds at other times. Numbers of species again, which, when adult, feed almost entirely upon grain, feed their young, especially during the early stages of their existence, upon insects; while others are exclusively insect-eaters at all times of their lives. All these points must be considered by those who would succeed in keeping and breeding birds in aviaries.
It would be almost impossible to keep the purely insectivorous species, were it not for the fact that they can be gradually accus tomed to feed on what is known as "insectivorous" or "insectile" food, a composition of which the principal ingredients generally consist of dried ants' cocoons, dried flies, dried powdered meat, preserved or fresh yolk of egg, and crumb of bread or biscuit. This is moistened with water or mixed with mashed boiled potato or beef dripping, and forms a diet upon which most of the insectiv orous birds thrive. The various ingredients, or the food ready made, can be obtained at certain shops. Although it is a good staple diet for these birds, the addition of mealworms, caterpillars, grubs, spiders and so forth is often a necessity, espe cially for purely insectivorous species.
The fruit-eating species, such as the tanagers and sugar-birds of the New World, require ripe fruit in abundance in addition to a staple diet such as that above described, while for such birds as feed largely upon earth-worms, shredded raw meat is added with advantage.
Many of the waders make very interesting aviary birds, and require a diet similar to that above recommended, with the addi tion of chopped raw meat, mealworms and any insects that can be obtained.
Birds of prey naturally require a meat diet, which is best given in the form of small, freshly killed mammals, and birds, the fur or feathers of which should not be removed, as they aid digestion.
The majority of wild birds, from whatever part of the world they may come, will breed successfully in suitable aviaries pro vided proper nesting sites are available. Large bundles of brush wood, fixed up in sheltered spots, will afford accommodation for many kinds of birds, while some will readily build in evergreen shrubs if these are grown in their enclosure. Small boxes and baskets, securely fastened to the wall or roof of the sheltered part of an aviary, will be appropriated by such species as naturally build in holes and crevices. Most of the parrots, when wild, lay their eggs in hollow trees, and occasionally in holes in rocks, or in ants' hills, making no nest, but merely scraping out a slight hollow in which to deposit the eggs. For these birds hollow logs, with small entrance holes near the top, or boxes, varying in size accord ing to the size of the parrots should be supplied. In providing nesting accommodation for his birds the aviculturist must endeav our to imitate their natural surroundings and supply sites as nearly as possible similar to those which the birds would naturally select.
Aviculture is a delightful pastime, but it is also far more than this; it is of considerable scientific importance, for it admits of the living birds being studied in a way that would be quite impos sible otherwise. There are hundreds of species of birds, from all parts of the world, the habits of which are almost unknown, but which may be kept without difficulty in suitable aviaries. Many of these birds cannot be studied satisfactorily in a wild state by reason of their shy nature and retiring habits, not to mention their rarity and the impossibility, so far as most people are concerned, of visiting their native haunts. In suitable large aviaries, however, their nesting habits, courtship, display, incubation, moult and so forth can be accurately observed and recorded. The keeping of birds in aviaries is therefore a practice worthy of every encourage ment, so long as the aviaries are of sufficient size and suitable design to allow of the birds exhibiting their natural habits; for in a large aviary they will reveal the secrets of their nature as they never would do in a cage or small aviary. (D. S.-S.)