BIRDS
Within the past few years, interest in all aspects of our environment has increased in proportion to the damage we are doing to it. Birds form not only an attractive but an essential part of the environment. Yet the protection afforded to them is patchy, at best. Taking Europe as an example and France in particular, there is a custom in that country to shoot as many as possible of the small song-birds as they return north from their migration to Africa. They are considered a delicacy.
Of course the shooting of birds in Britain for sport as well as for food has been a tradition for centuries, but the shooting is restricted to game birds, grouse, pheasants, partridges and wild duck. Except for the wild duck, these species are hand-reared and fed by gamekeepers, the numbers shot are limited, and the shooting-season, which begins on 12th August, ends well before the breeding season begins. Thus, the game species are well preserved.
For many years steps have been taken to maintain, if not increase numbers of all types of birds. The Royal Society for the Protection of Birds keeps a careful watch on preservation, and has instigated laws against the theft of eggs, which are rigorously implemented. Many sanctuaries for water-birds as well as songbirds have been established up and down the length of Britain. The public in general has been educated to place a high value on the bird-life of their country.
Yet for reasons other than shooting and theft, various species seem to dwindle away to the point of extinction, causing widespread concern. For many decades, habitats have been systematically destroyed by the clearance of woods and hedges to provide the large fields needed for modern agriculture. Secondly, certain chemicals used to keep crops free from pests also destroyed the food on which many birds survived. Today, the problem is realized, and attention is given both to habitat and food, with the result that many species have been saved. Some chemicals, which also poisoned the birds themselves, have been banned. Wide strips between fields are left in their natural state to provide cover and nesting facilities. Many woods and coppices have been replanted with the traditional varieties of trees instead of the cash-crop conifers. Sea and marsh birds have been encouraged to return by exerting some control over land reclamation. In many countries, the protection of birds is being given a high priority.
Birds are appreciated for their beauty and their song. However, neither faculty exists merely to please the human race. The colored plumage of many male birds has the function of impressing females prior to the mating season. Birdsong may have the same purpose at that time, though some of it seems to be simply the expression of joie de vivre and perhaps a means of staking out territory. The writer visited Belsen concentration camp shortly after its liberation. There was an eerie silence about the place. During and for some time after the holocaust, no bird came near the camp. So there may indeed be an emotional as well as a practical aspect to birdsong. Another practical function is to warn against predators and if possible scare them off.
Birds play an essential part in the cycle of nature. They may and do raid crops, but they also eat grubs and insects which do far more damage. They also have a role as scavengers; that work is completed by the insects, which in turn fall prey to the birds.
A few species, the ratital, have become flightless through natural selection. These are the emu, the ostrich, the rhea, the kiwi and the cassowary. The vast majority, the carinatal, are wonderfully adapted to flight, some being capable of spending most of their two to three-year lifespan on the wing. The muscular power of their wings relative to body-weight, and the aerodynamic efficiency of their wingspans and feather distribution, developed over millions of years, is one of nature's marvels. That is why the loss of so many land-birds through insensitive agricultural development, and of sea-birds through oil-spills, is such a tragedy.
Another class of birds under threat and forming an essential part of the natural cycle is the predator; owls, hawks, eagles etc. These control small rodent pests and act as scavengers. Some also provide the sport of falconry, being to some extent amenable to human control.
Perhaps the most wonderful feature of the bird is its ability to navigate so accurately in migrating. Its high body temperature and stamina can be built up to sustain amazingly long journeys, but the way in which the Arctic tern, for example, can fly direct from pole to pole, selecting just one small island stop en route, is not fully understood. Theories are manifold, but since fledglings with no experience perform this miracle, much still remains to be learnt.
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