Glasgow Zoo Park
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NATURAL HISTORY AT CALDERPARK
The Zoological Society of Glasgow and West of Scotland acquired the 40 hectare site at Calderpark in 1939. Although designated today as "degraded Greenbelt" because of past and continuing uses for industry (e.g., the Calderpark pit-head, mineral railway and pit bing (or ash spoil heap)), the site also includes three kilometres of a tributary of the Clyde - the North Calder Water - running from North-East to South-West, sheer Devonian red sandstone and Carboniferous shale cliffs (up to 50 metres in height), a one hectare lake (Webster's Pond, an abandoned North Calder meander), two hectares of original elm/ash native woodlands (believed totally untouched by man, and containing no exotic species), and fifteen hectares of parkland around the site of Calderpark House (demolished in the early 1930s because of mining subsidence). This parkland contains many fine specimen trees, some (sweet chestnut, cut-leaved beech) growing on the northern limit of their range in Europe.

After occupation of the estate for many decades (possibly centuries), the estate was unoccupied for two decades prior to construction of the Zoo, which commenced on the western portion of the site in 1946. Since then there has been a daily presence by employees, with twenty-four hour cover, at least since the early 1970s. During this period, with the exception of some pest control (rats, rabbits, foxes - though not for many years) and occasional air-gun damage (grey squirrels), the estate has been protectively managed to conserve its natural history. During the late 1970s to mid-80s over 120,000 trees and shrubs were planted with one result being the extension of the feeding/foraging ranges of free-living badgers throughout the Zoo.

Of course the key to the survival of wild animals is the maintenance of habitat, and the lands of the Zoological Society of Glasgow and the West of Scotland provides a stable environment for them. You can help us go on providing that stable habitat by sponsoring these animals.

Birds at Glasgow Zoopark

Glasgow Zoopark provides a great opportunity to see a multitude of wild birds both on site and close by. Click here for a checklist.

BADGERS

Badgers have been a feature for many years, probably centuries. We are proud of this and used to be unguarded with this information until the Lanarkshire Badger Watch warned us that illegal badger digging and badger baiting still occurred in the area. Sure enough, we have subsequently repelled groups of men with long-handled spades and teams of lurchers and terriers from the undeveloped land near the lake close to one of the occupied setts.

Although setts can be found on both sides of the North Calder Water, it is clear to us that they are connected; from time to time - admittedly some years ago now - the keepers have come across individual badgers, stumbling around and clearly ill and disorientated. We soon found out that they had been eating poisoned earthworms and/or the slug-type bait put down on the golf course to control earthworms on the greens. Treatment by the vet, and peace and quiet for two or three days in a empty loose box in the camel/cattle house, and the badgers made complete recoveries.

With the heavy planting of trees, lawns and shrubberies, badgers can be encountered in the evenings and during the night in all areas of the Zoo. Their runs are well marked, and we make a point of keeping their traditional access points clear.

In June, in some very productive years the young badgers on the golf course become so used to humans, that they forage in full view, which some people find disconcerting. We have received appeals in the past for some of these 'surplus' young badgers to be 'translocated', but this is a complicated procedure for a heavily protected animal, requiring licences, etc., so best left to the local officer of Scottish Natural Heritage.

Click here for more on Badgers.

RED FOXES

With a river and much natural habitat on the site, foxes are ever-present. There are usually one, possibly two pairs, with one den in the valley just to the north of the Black bear fence, and another den by the riverside beyond the cattle/camel paddock.

Foxes caused us few problems until we started to keep peafowl, guineafowl, jungle fowl and the animals of the Children's Farm at semi-liberty. This coincided with the regular use of a high-sided skip and all rubbish having to be moved off site at least twice a week. We now know that all peahens incubating eggs naturally in long grass will be hunted out without fail, so any eggs found are lifted, if possible, for artificial incubation under bantams in the Children's Farm.

The late, Lanarkshire-based naturalist, David Stephen, whose book String-lug, the Fox was a seminal influence on the Director several decades ago, used to argue vehemently that people should learn to co-exist with their resident pair of foxes. Removing them just creates a vacuum into which wandering foxes are soon attracted. This advice, which we follow, certainly stretches the patience, when after a fruitless night's scavenging the dog fox hides in the shrubbery until the poultry in the Children's Farm are let out in the morning and then snatches two or three, in broad daylight, sometimes as late as 10 am. We have now taken to deliberately feeding the foxes, with the bonus, we think, of cub-watching for visitors during light June evenings.

Tracking the progress of a fox in the evening is greatly facilitated by a) their predictability - leaving their den at 9 pm to 9.20 pm onwards unless it is raining, and b) the cacophony of angry cackling set up by carrion crows, rooks and particularly magpies as they harass the fox on its rounds. With a 100-nest rookery there are usually one or more baby rooks on the ground in June and it is salutary to see the dog fox unerringly head straight there, to return twenty minutes later with a limp bundle of black feathers. No wonder the adults sound so furious.

Click here for more on foxes.

AMERICAN MINK

These very unwelcome interlopers first appeared in 1982, travelling east along the banks of the North Calder River. All the examples we have observed have been of the chocolate brown, wild type. Sometimes we can go for months without seeing one, but then more dead waterfowl tell their own dismal story, so much so that we have now stopped using the riverside paddocks for any sort of vulnerable birds.

Despite their depredations, their presence can have its lighter moments. In 1985, one of the volunteers, a very strong and enthusiastic young man, greeted the Director as he drove into the Zoo, by triumphantly emerging from behind a low beech hedge clasping a wriggling creature with both hands:
"Mr O'Grady, I've caught the escaped ferret from the Education Department."
"But we haven't lost a ferret," he replied, simultaneously noticing hands and arms dripping with blood!

Click here for more on Mink.

GREY SQUIRRELS

The earliest recorded introduction of Grey squirrels to Great Britain was in 1867 when a pair was liberated at Macclesfield in Cheshire. In Scotland, a pair was liberated at Finnart on Loch Long in 1892, on the borders of Dunbarton and Argyll. From here they spread northwards to Arrochar and Tarbet by 1903, east to Luss by 1904, and to Inverbeg 1906. By 1907, they had spread to Garelochhead, Rosneath 1915, and south to Helensburgh, Alexandria and Cardross by 1912. By 1915 they had spread to the east side of Loch Lomond and Drymen in Stirlingshire.

In 1913 Grey squirrels were introduced to Edinburgh Zoo from where some escaped and colonised Corstorphine Hill, with other introductions at Pittencrieff Park, Dunfermline in 1919 and Ayrshire and North Queensferry in Fife in 1929. These fresh introductions undoubtedly introduced fresh blood, and by the mid-1950s extensive areas of lowland Scotland had been colonised. Where Grey squirrels were not present it was usually because some natural barrier, e.g., a lengthy expanse of treeless moorland, had prevented their immigration.

In the space of about a hundred years, this interesting animal has thoroughly colonised most of Great Britain, with consequences upon the native Red squirrel population which are still being studied and analysed.

We have always had plenty of Grey squirrels, which cause us no problems at all, and are a great delight to visitors. July is a lean month for wild Grey squirrels, with some squirrels dying of starvation before the Autumn harvest, but not here - July is usually our peak month and the visitors leave plenty of scraps which the squirrels enjoy, quite apart from what they can rely on in the animal enclosures.

Grey Squirrels

Glasgow Zoopark maintains a significantly large population of wild grey squirrels focussed on the area around the Tropical House and Children's Farm, down to the Car Parks, and across to the Tiger House, Small Primate House, and spreading out less densely into the Calderpark woodlands alongside the river behind the Ankole Cattle.

The density is in my opinion abnormally high, especially this year where the all year-round supply of zoo food has been boosted by an abundant crop of acorns and hazelnuts, and some beech. As the area described is also visibly part of the former Calderpark Estate and parkland, oak and beech trees are regularly spaced throughout the site.

The favoured zoo food ranges from cubes of bread, some fruit, ungulate, bird and pig pellets, to the most favoured peanuts in their shells, (used as scatter feeds for the Porcupines and Collared Peccaries).

In November, with the young of the year well grown, population levels seem at their highest. This reminded me of South Carolina in 1997 where the area around the Airport on Hilton Head Island seemed to carry a similarly large population. The difference seemed to me that the American squirrels were more dispersed, and clearly feeding on natural foods, particularly the cones of the numerous pine trees. It was also much warmer and the squirrels had thinner coats, suggesting a much lower energy requirement to that of our own squirrels.

What has struck me this year in particular are the high numbers of aggressive interactions amongst our squirrels.

Whilst we have always tried to run the land occupied by the Zoopark (40 acres developed, 95 acres in total) as an ad-hoc nature reserve, I have been well aware - though I could never catch them - that certain locals and one former member of staff regarded grey squirrels as vermin and would shoot them with air-guns - or, so I was told, and certainly that was the way they talked about them.

I would find the occasional dead grey squirrel, usually unmarked, and would assume that it had either been shot by an air-gun, or died of some virus. I confess, I never seriously considered having one post- mortemed.

My purpose for writing is that this year, 1998, I have been very struck by the sheer numbers of aggressive encounters I have witnessed between squirrels. A squirrel bridge highway of a heavy electric cable, crosses a road just outside my office window, joining the building four metres from where I sit. This highway leads directly from one oak tree to another oak tree. Both are positioned in the middle of large enclosures.

I have become very used to the normal vocal communications of grey squirrels and always stop to take a look when I hear a squirrel scolding outside. In the past I assumed this was in response to a cat, and often it was.

However, this year, nearly allof the aggressive scoldings, accompanied by tail flicking, has been emanating from one squirrel chiding another. It can continue for a long time, well over half an hour on some occasions (when this takes place 10 metres away, it takes the form of a stuttering electric drill if you are trying to concentrate). Normally, one squirrel is facing another, who is usually frozen, silent, watching intently from about three metres away. Where they are closer, worst of all when one squirrel has another trapped against the wall with their head close to the masonry, even if you chase them apart, you invariably find a dead squirrel (superficially unmarked) in the immediate area, a day or two later. Killed, it appears again to be unmarked though a tooth through the skull might not leave much visible evidence perhaps?

Was this aggression, as I believe it was, perhaps triggered-off by over-high populations focussed on relatively concentrated feeding points? Or, was the second squirrel already ill in some way, and in consequence being singled out by the others?

Click here for more on Squirrels

See also the Wildlife garden as a teaching resource

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