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Practical Protection of Birds

Many useful birds, mainly insectivorous species, are declining in number every year. They build their nests in dense thickets where they forage for food. Their homes in the undergrowth of hedgerows, alongside paths and on the margins of woods are often destroyed and they are de-prived of their habitat. Many are unable to adapt themselves to the new conditions and are aban-doning their homes. The shrike has an inborn instinct to build its nest in thorny thickets in open country and cannot live, for instance, in a spruce wood, nor will it build its nest on the ground in a field, like the lark. Individual pairs of nesting birds cannot squeeze into the remain-ing suitable localities for each pair requires a specific space for nesting and this cannot be continually decreased.

The only remaining way to preserve birds in their original homes is to plant trees and thickets on such land as cannot be used for agricultural purposes - on slopes bordering roads, in aban-doned quarries, alongside brooks and field boundaries. Not only will many birds build their nests here but these places will also provide shelter for hares, deer and other small wild game. Best suited for the purpose are shrubs that bear edible fruits or berries, especially in the autumn and winter, providing a source of food for birds at this time, e. g. hawthorn, snow-berry, blackthorn, privet, cornel cherry, elder-berry, sweetbriar and dogwood, and trees such as mountain ash, birch and alder. Field bound-aries should also include several small oaks, lime trees, pines, and spruces in whose thick branches many birds build their nests. Naturally, the planting of field boundaries is not primarily an individual concern but the responsibility of na-ture conservationists and local authorities.

Nevertheless, even the individual can contri-bute to the protection of birds nesting in thick-ets, mainly by planting green hedges around the edges of gardens and parks. The best hedges are hawthorn, hornbeam, common maple, privet and dogwood. Green hedges may be planted even close to a house; small birds are generally not disturbed by the presence of man and can coexist. It is important, however, to trim the hedges every autumn, for this makes them thicker. Single trees and shrubs in gardens will also attract many birds. Particularly suitable for this purpose are ornamental spruce trees with close-set branches as well as various juniper trees. Warblers are often quite satisfied with thick gooseberry bushes. The small birds which are thus provided with a shelter will reward us by destroying troublesome and harmful in-sects.

Widely varied species of birds seek the sanc-tuary of parks and large gardens thickly set with ornamental shrubs and old shade trees as well as conifers. Even woodland birds sometimes make their homes there for the environment is similar to their native habitat and affords countless op-portunities for nesting. Owls, too, may be found there as well as cuckoos. This is one of the principal reasons why such oases of greenery in the heart of large cities should be cherished.

Special note should be taken of birds nesting in cavities. Natural cavities are to be found chiefly in old trees, which are often cut down nowadays, thus depriving the birds of nesting opportunities. Some seek substitutes as a hole in a hollow tree stump or pile of stones, but the clutch is vulnerable to attacks by small predators and stray cats.

Tits are typical tree cavity nesters in parks and gardens. They play an important role in the biology of life in the wild, being among the best eradicators of harmful insects. Simple acts such as putting up a nest box and food out during the winter months can help increase their number to such an extent that they will help keep the insect population within reasonable limits. Nest boxes especially attract the great tit and blue tit to the garden. Any box will do, whether made by hol-lowing out a tree trunk or by nailing together a few boards. The former resembles a natural cavity for only the roof is made of wood and fashioned so that it can be opened by tilting up or sliding out to make cleaning easier. However, it requires a bit of work and it is liable to crack in the second year if the trunk does not happen to be sufficiently dry. On the other hand, nest boxes of wood are very easy to make and can be constructed of inferior wood. The boards should be placed close together without any cracks in between and the bottom should be fitted be-tween the walls to prevent the entry of water during a downpour. Two or three small holes should be bored in the bottom, however, to allow any water that might have penetrated to run out. The roof should be either removable or ,fastened with hinges so that it can be opened. The entrance hole should be located in the upper third of the box wall, best of all in the centre, though it may just as easily be made in the corner. A natural entrance hole is always circular, but many birds have no objection to a square one. A perch should not be put in front of the hole for it not only hampers the bird's entrance (it flies straight into the hole), but also makes it easier for pests to get in.

Nest boxes should not be nailed directly to a tree branch but onto a baseboard that may be attached front to back or even from the side. Some boxes may also be suspended from a branch.

The best kind of box for a blue tit or other small bird measures twelve centimetres square and twenty centimetres high with an entrance hole twenty-six millimetres in diameter, hung 1.5 to five metres above the ground. There is no danger of its being usurped by a house spar-row for the latter cannot squeeze through such a small opening.

For the great tit the nest box should be the same size, though it may be five centimetres higher, but with an entrance hole thirty-two to thirty-five millimetres across. Other tits, the col-lared flycatcher, pied flycatcher and sometimes even a European redstart or black redstart may nest there. In gardens sparrows will readily use such a comfortable refuge. The great tit, how-ever, is not put off by such an intruder and will chase out the sparrow, throw out its nest and build one of its own.

Nest boxes fifteen centimetres square and twenty-eight to thirty-five centimetres high with an entrance hole fifty millimetres across are favoured by the starling, but may be used also by the nuthatch and sometimes even the great spot-ted woodpecker. Woodpeckers, however, often chip the opening with their strong bills and thus sometimes wreck the box. For that reason in neighbourhoods where woodpeckers are plenti-ful it is worth nailing a piece of plywood with a hole of the same size on the outside. These Owls, too, can be helped during the nesting period. Boxes for owls, of the aforementioned size, should be fastened to a tree at the edge of a wood so that the owl can hunt in the surround-ing fields. For the little owl and Tengmalm's owl the nest box should be about twenty centimetres square and thirty-five centimetres high and the entrance hole should be about ninety mil-limetres across. Small owls, such as the pygmy, will even make use of a sparrow's nest box. Boxes for this owl should be hung four to eight metres above the ground.

Certain water birds can also be effectively protected, chiefly during the breeding season.

It is essential that the greatest possible quiet be maintained on ponds, lakes and pools, par-ticularly in reed beds, so that birds are not disturbed unnecessarily while incubating and so that they can care for their offspring as they should. Great harm can be caused by freely roaming dogs, which flush sitting ducks or other birds, some of which abandon their nests al-together if disturbed. Also important, however, is to provide sufficient places for concealment. Ducks, and naturally other birds, too, need to feel safe and this is possible only in thick stands of reeds, rushes and grass. That is why the continuous belt of the previous year's reeds should be preserved on the edges of all ponds, and on the lakes where reeds and rushes are harvested they should be left standing in some spots where ducks and other water birds can seek shelter, especially in spring before the new vegetation has grown in. Most important for ducks are open stretches of water, only partly covered with reeds and low clumps of grass. To leave some of these untouched, therefore, is a must and need in no way be an obstacle to successful pond management. Old stands are a good shelter also for grebes, rails, gulls and many other species of birds. Reeds that are left standing, however, should be Located alongside shallows where the offspring of various species of ducks forage for food. Another cardinal rule should be never to cut reeds during the nesting period for such harvesting is responsible for the death of many nestlings or the destruction of eggs.

A suitable spot for ducks to nest is an islet or several islets on a larger pond; these islets may also be at the edge of the pond. Overgrown islets have a great many advantages. Ducks are fond of building nests there close to water, and on such islets the nests are not in danger of being flooded if the water level rises. Furthermore, vermin find it difficult to reach such islets and in addition to that the birds are not as exposed to disturbance as on the shore. Also clumps of grass on the shore are a good place for ducks to build their nests. Wooden nest boxes can be placed to good advantage in reeds and rushes as well as on islets, where many species of ducks will lay eggs and rear young. The nest boxes should be located above the highest probable water line and a wooden ramp with crossbars should be affixed to the opening. This makes it easy for the birds to enter no matter what the level of the water, which thus cannot affect the successful outcome of incubation. The nest box-es should be about seventy centimetres long, forty centimetres wide and forty centimetres high, with an entrance hole twelve to fifteen

centimetres in diameter. They should be impreg-nated with a water-resistant substance so that they are impervious to damage from damp. The nesting hole itself, which should be separated by a low wooden partition, should be lined with some turf and soft, dry leaves and moss. For ducks that nest in tree cavities, e. g. Goldeneye, the nest box should be placed in a tree beside water. Such a box should be about seventy cen-timetres high, forty centimetres wide and the entrance hole ten to twelve centimetres across. These nest boxes should be lined similarly and a shallow depression made so that the eggs do not roll out.

On ponds we can also provide ducks with flat feeding boxes that either float on the water or else are attached to wooden piles about thirty centimetres above the surface and reached by means of slanting ramps. A roof above the box serves to keep the food dry when it rains.

With such fairly inexpensive constructions it is possible to increase the number of ducks and other water birds.

When bogs and swamps are being drained some spots should be left intact in certain areas so that water and marshland birds which nest there do not move away, thus impoverishing the local fauna and characteristic stamp of the given countryside.

Suitable nesting conditions can also be pro-vided for certain sea birds, thus helping to in-crease their number. For the common mer-ganser (Mergus merganser) wooden nest boxes may be put up in a tree 2.5 to eighteen metres above the ground. These should be about eighty-five centimetres high, twenty-three to twenty- eight centimetres wide, with an entry hole twelve centimetres across.

For the eider (Somateria mollissima) hollows of stones or tree trunks, placed so they can build their nests underneath, will also provide more opportunities for nesting.

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