Whilst the biology of Glasgow may not be rich in world rarities, it is fascinating, important and valuable despite that. It may resemble that of Edinburgh, Birmingham or even New York more than it does the Renfrew Hills or Loch Lomondside, but it can still demonstrate the principles of ecology, genetics, physiology or animal behaviour; often more clearly and with less ecological damage than the inaccessible and fragile habitats of the Highlands. Like all cities, Glasgow has its wildlife, a fascinating spectrum of plants and animals that share the same environment as you or I. In the summer swifts fly around the towers of the University and Museum, ospreys may rest at Possil Loch on their annual return to their highland eyries at Loch Garten and elsewhere, and kingfishers now regularly fly, feed and nest along the Cart and Kelvin.

Yet we really know very little of the nature of urban wildlife, of why some animals or plants thrive in the town whilst others, near neighbours living happily in field or wood, have never been seen in Glasgow, nor of how important they may be to us and to the 'balance of nature'.

Not all the wildlife habitats in and around Glasgow can be counted as equally exciting. The sites recognised as having the greatest biological value are very much peripheral to the city itself. Possil Loch is one of the best known of these. Lying between Balmore Road and the Forth and Clyde Canal and less than half a mile from the housing estates of Milton and Kenmure, Possil Loch was once no more than a boggy patch adjacent to the extensive Bishopbriggs Woods. It seems to have become wet as a result of mining subsidence beneath; perhaps aided by the construction of the canal next to it. Since then it has possibly introduced and inspired more Natural Historians than any other site in Scotland, even though the gradual encroachment of the city over the years has driven away the little grebes and otters that once lived there.

The vegetation pattern, too, has changed a lot. Once it was surrounded by woodland, but the larger trees have been removed to build ships and fire furnaces; once it was a sphagnum bog with large patches of the insect eating sundew, but the changing water level has drowned them out. At present it is a willow carr and reed bed surrounding a large area of pen water.

It is probably this area of open water that is it's most important asset at the moment, acting like a magnet for a host of migrants passing both north and south. In spring and autumn a variety of ducks and swans, including the rarer whooper swan, swim and feed in its waters, whilst wagtails, warblers and swallows fly around the marsh before setting in the reeds or willows for the night. These migrant groups are of interest for three reasons: for their absentees, few geese or waders find the deep turbulent waters attractive preferring the flooded fields of the Kelvin Valley less than a mile further north; for the flight displays, for many people the pinnacle of aesthetic experience; and for the occasional rarities whose presence for a few days may excite and attract the world of ornithology.

The natural woodlands that extend along the valleys that cut into the hills skirting Glasgow's edge also bear witness to a rich profusion of wildlife that once must have dominated the Lower Clyde Valley. Walking the nature trail in Linn Park will give you some idea of the variety and interest of these valley woodlands. Perhaps most surprising is the diversity of tree species. Oak, ash, elm, birch and sycamore vie to dominate the highest canopy, whilst holly, bramble and rhododendron, as well as alder and willow at the water's edge, compete to fill the spaces below. Of course, very little of this silvan pattern is completely natural. Most of the oak which once clothed nearly all of Glasgow has been cut down to make space for the city, to build ships and to fire furnaces. Hazel, ash and elm might have been regularly cut or coppiced for firewood or furniture. New exotic species, like the rhododendron, will have been added to provide aesthetic pleasure to a policy woodland. All these historical features are visible and make fascination learning in the valleys of Glasgow. Equally interesting are the associated plant communities that make up the ground flora of these valley woodlands. Ferns, mosses and liverworts, sometimes rare and usually with unpronounceable Latin names and no Scottish equivalent, are common, especially in the wetter places. Here, too, you might find alternate leaved golden saxifrage, broad helleborine, wood stichwort, pellitory of the wall or the creeping New Zealand flax, a recent interloper from the antipodes. It is probably these ground flora communities, especially of the wetter flushes and dripping gorges, that have changed least during man's occupation of Glasgow.

For many species the ecological importance of these valleys, snaking in towards the city centre, lies in the passage they provide from country to town. It is along these corridors that kingfishers, woodpeckers, orange tip butterflies, figwort, sorrel, bluebells, roe deer, bank voles and perhaps even otters may reach into the city. Their connecting value, at least for the major water courses of the Cart and Kelvin, has also been appreciated in the context of a walkway network joining existing parks to each other and to the wider countryside. Perhaps more could be done for some of the smaller streams that remain uncovered and presently attract little but litter.

Most of the remaining woodland in Glasgow is associated with its extensive and famous network of parks. A great many of these were bequeathed or given to the old Glasgow Corporation by the great landowners whose land was being swallowed by the city's rapid expansion at the turn of the century, a legacy that can be matched by few other cities in Europe. Fortunately these policies were not subject to the same excesses as the landscaped estates of southern England and retained much of their natural woodland origins, although inevitably many additional trees were planted as gardens around the estate house. It also means that Glasgow's parks have a rich flora and fauna. Pollok Park, which pushes into the heart of the city's south side is one of the best. Here, in an area of over 300 acres (it was more until the M77 was pushed through it), can be found one of the most extensive areas of public woodland in any European city. Rhododendrons, azaleas, magnolias, prunus, maples, chestnut, pines, firs, beech, elms, lime, native and foreign oaks and many more find space in the attractive garden landscape of the estate. It is chastening, wandering quietly in these undisturbed surroundings out of sight or sound of the enclosing metropolis, to realise that most of this woodland is man made, a landscaped garden in which planted trees have replaced and supplemented oak, birch and pasture. Yet beneath fox, roe deer, badger, squirrel and woodpecker survive successfully, and a book has been written about the 125 mushrooms and toadstools that live on the ground and decaying trees of Glasgow's Parks. In Pollok, too, can be found a herd of Highland cattle, a hardy breed now finding commercial interest from the mountainous regions of northern Europe to the wild, cold wastes of Patagonia but still out of favour (except to please the tourists) in our own uplands.

But Glasgow's wildlife comes closer to the city than that. Even the office, shop, factory or tenement window can offer more than a glimpse of the city's animal inhabitants. If you are near the urban motorway network, watch for kestrels hovering above the grassy embankments before they swoop on an unsuspecting vole or shrew. Sparrowhawks regularly quarter the city's waste places in search of small birds. The starling roost in George Square, despite the periodic attentions of the Environmental Health Department, is one of the oldest in Glasgow whose members fly daily out and back along regular flight lines which might well pass directly past your window.

Land left vacant in Glasgow is often not only an eyesore but a biological desert in which only a few species are present. Yet some waste patches have character; often with the purple of rosebay willowherb, perhaps an expanding group of young sallows or the yellow of ragwort and trefoil. Some of the attractions are truly exotic. Both the pale purple flowered balsam, which also brightens the riverbanks, and the giant hogweed, an annual ten feet or more tall with irritant, protective hairs, are both plants introduced from Asia by horticulturists. Many of the successful plants of urban waste spaces come in from such foreign sources. The Oxford ragwort is a native of Sicilian lava fields which has used the burnt cinders of the railway system and the destructive force of the war to reach most cities in Britain -with the exception of the two colder northern cities of Glasgow and Aberdeen. Its arrival in Edinburgh's waste places can be dated to 1953, yet in Glasgow it is still a rarity. The yellow on Glasgow's waste lands is more likely to be the springtime coltsfoot, or the less seasonal groundsel and common ragwort. Sometimes truly unexpected rarities are still recorded around Glasgow's docks where they have been blown from a ships hold or trampled from a sailors boot.

If a waste place is large enough, or has been left undisturbed long enough, it is amazing what a variety of wildlife can be found. In the 76 acres of Cunnigar Loop, in the east end of Glasgow, lies an area of deserted industry and mining surrounded by decaying warehouses and the River Clyde. Within this urban wilderness 116 different bird species have been recorded, including great crested grebe, hen harrier and green woodpecker; urban foxes nightly patrol for shrews, voles and mice; rich willow scrub provides nectar for bees and moths; butterburr, bulrush, celandine and the uncompromising giant hogweed vie to clothe the water's edge; a multitude of flies and midges offer a summer feast to swifts, skylarks, house martins and bats swooping low over the grassy vegetation; and larger moths and butterflies attract the eye of the observant naturalist. One of the more interesting of these is the elephant hawk moth, whose harmless caterpillar has alarmed even toughened building site workers. Both larva and adult are associated with the pink flowered rosebay willowherb, another alien interloper which has found conditions on wasteland to its liking and has spread throughout all British cities and much of its countryside as well. The adult hawk moth is an attractive pink winged species, perfectly camouflaged as it rests or feeds on its hosts large flower heads. The larva feeds on the leaves of the willowherb and is marked by two pairs of eyespots to deter would be predators. Once a comparative rarity, this moth has followed the march of its vegetable companion across Britain from the Surrey Docks to the Cunnigar Loop.

Such places make ideal environmental workshops. An opportunity to learn about the interrelationships of plants and animals and of these with man. To learn about caring for the environment, or just to learn to count or draw. For example counting hogweed stems may not initially seem too exciting, but this common umbelliferous plant is host to both larva and pupa of one of the many smaller moths. In the autumn the greenish brown caterpillar bores its way into the dying but persistent stem, pupating inside to await late spring when it will emerge in its adult form. This, however, is not the end of the story, for the pupa itself may be host to the parasitic caterpillar of a wasp-like ichneumon fly. An enterprising study, counting, rearing and drawing the story's various participants, which surely could not fail to captivate and educate an audience of any age, ability or education timetable.

It is no use describing the wildlife of Glasgow as if it has always been there and always will be. The opposite is probably true, of all ecosystems it is probably the most rapidly changing. The heavy pollution of a few decades ago has gone, the air is cleaner, the Clyde is cleaner. Nor do you need a chemical test to prove it. Nature provides many for you. Lichens, those grey, green, black or orange splashes on walls and tombstones are coming closer to the city centre. You can see the changes in action and build a map of the pattern of air pollution around the city. Each species of lichen, and there are a great many, responds differently to the levels of sulphur dioxide in the air so that some can live quite close to the city centre whilst others cannot get closer than twenty miles or more.

When the Clyde was at its most polluted, from the 1900's to the 60's, few creatures save the bacteria, the common eel and the tiny red wriggling worm called tubifex, familiar to most aquarists, could survive in Glasgow's river. The new cleaner Clyde supports far less of these small relatives of the earthworm, but there are still many millions left for cleaner does not mean clean. An indication of the improved quality of the Clyde waters can be found in the well publicised arrival of cormorants and salmon, or in the catches of flounders on the bottom muds. But evidence is perhaps best sought by tracing the increasing variety of small bottom living worms and molluscs, like the dark green paddle worm, that can be found nearer to Glasgow year by year.

It is not only through the negative effects of pollution that the population of Glasgow affects its wildlife. Large numbers of cats and dogs now occupy the vacuum created by the virtual exclusion of native carnivores from the city (with the exception of a few foxes, owls and kestrels). It is estimated that Glasgow may have 80,000 dogs and 50,000 cats, one in five of which are likely to be living, at least partially, wild in the city. For the dogs alone this amounts to a calculated deposition of 3,000 gallons of urine and 20,000 lb of faeces per day. The household pet is unlikely to exert any marked predatory pressure on rodents or birds in its locality, but a neglected or truly feral cat or dog may have considerable influence. Feral cats prey predominately on mice and other small rodents. Unfortunately this will make little impact on the brown rat population which, from studies elsewhere, might number anything between 25,000 and 150,000.

Domestic refuse forms the principal food of stray dogs, although many are also fed by their owners or other people. But stray dogs have a different social pattern to cats or foxes and will often form small packs of three to ten individuals, to which a wandering pet may often attach itself. Whether these packs have any particular influence on other animals or man is difficult to judge; the numbers of young children bitten, or sheep harried on urban edge farms, are statistics that are not regularly collected.

Glasgow also has its fair share of urban foxes, particularly in the wilder parks, waste spaces, river and railway banks where they will often occupy old rabbit warrens. Although getting closer to the city centre, foxes show surprisingly few direct adaptations to city life. Their breeding and social behaviour do not seem to have changed in adapting to the urban environment. In fact the fox is one of the few successes in town that has, like man, a 'family' social unit.

The paucity of 'valued' habitats, communities or species in a city like Glasgow should not lead to neglect, for these are compensated by their ecological strength, tolerance and availability. Glasgow's wildlife is a rich and unique environmental resource that, however, requires help in its management and use. We must understand its importance, learn how best to encourage it, and, most of all, make full use of its educational and social potential. In attempting to do so, we must remember the streams, ponds, woods and waste patches that create an interlocking network of habitats whose pattern and character is constantly changing around us and with us.