Aviary and Enclosure
Design and Construction
 

 4.       ENCLOSURE CONSTRUCTION

Please click on thumbnail pictures to enlarge

As with the previous chapter I guess the best place to start is with the perimeter fence and again I would remind you that I am only going to talk about enclosures that my wife and I have built or those of which we have had first hand knowledge.

Macropod Enclosures

Perimeter fences can be comparatively simple to erect provided you follow a few simple guidelines.    The first thing to do is to determine where the fences are going to go by marking them out with pegs and/or stringlines which is the way I did it, not being familiar with ‘high tech’ items like dumpy levels, but, of course, please feel free to use any methods at your disposal with which you are comfortable.     All the perimeter fences we have built have been of the same type, which we have found to be economical and yet very effective.    These are made using permapine posts with four straight wires from which to hang the wire mesh.

Our first attempt at fence building was erected in the Adelaide Hills in 1984, (see Figure 1 in part 3) was a little under 500m (1,640ft) in length and is still standing the last time I saw it in late 2001.    It was designed as an upside down ‘T’ shape with a width of wire laying flat on the ground that was attached with ‘hogrings’ to the vertical portion of the fence and the whole thing was basically made of chicken wire hung from tensioned straight wires.     The climate in that area has had snow on rare occasion’s right through to temperatures in the mid forties (degrees C).      The property was at the peak of a hill that had medium tree cover and a very ‘rocky’ ground.    It was a five sided area of about one hectare (2.5 acres) and the fence contained the whole acreage.

As this was the first feral proof fence my wife and I had erected and we cheated somewhat, in that four of the five boundaries of the property had an existing sheep and lamb fence with concrete posts already in position.     This was in reasonably good order, so we used it as a basis for our feral proof fence.

The concrete posts of the existing fence were at 12m (40ft) intervals with a steel dropper at the midway point.     It consisted of a sheep and lamb mesh topped with two barbed wires.    Personally, I do not like barbed wire and as far as I can see, is of little use anyone.    Animals of all types still get mutilated by this stuff without it seeming to have any deterrent effect.    But I’m digressing.

The first thing we did was to remove the barbed wire in the places where I thought it likely to cause problems later.    The sheep and lamb wire was left in place and actually became quite useful when we were attaching the new wire.

We used 2.4m (8ft) permapine posts which were then attached to the concrete posts by drilling 12mm (”) holes in each one and bolting them together with 10mm (7/16”) Hex head galvanised bolts.    The existing midpoint droppers were also left in place and we bought some 2.4m (8ft) lengths of lightweight galvanised steel tube as droppers for the new fence.

There were 52 poles that had to be attached to the existing concrete posts and we found the most difficult and time consuming job of all was drilling the holes in the concrete posts.    To put it bluntly it was a s*** of a job and took me a whole weekend.       Tip: don’t ever try to drill a 12mm (”) hole into a concrete post in one go or you’ll probably stuff up your drill and/or your drill bit.     Do it in stages, it’s much easier for you and kinder on your tools.    Because I had such a lot to do I did it in three stages by starting with a 4mm (3/16”) drill then an 8mm (3/8”) then finished off with the 12mm (”).     The next job was to drill holes through each permapine posts at about 150mm (6”) down from the top and at about 1050mm (3’6”) down from the top.    These holes were to be used for threading a single strand 2.5mm galvanised steel wire from which we would hang the mesh.    In this case, apart from the holes to bolt the poles to the posts, there was no need to drill through the posts lower down because we had the existing sheep and lamb wire from which to hang the mesh.  

For the boundary that did not have an existing fence we used 3m (10ft) poles and dug holes about 600mm (2ft) deep which we backfilled, after inserting the pole, with the soil that came out of the hole mixed with a little dry cement.     The first post from each corner was placed at the 3m mark and then at intervals of 12m and a steel dropper midway between.   The corner posts were braced each side using a horizontally pole from the corner post to the post at the 3m (10ft) mark and were also wired diagonally. (See figure 5)     Since building this fence we have now built a second one without the advantage of being able to use or add to an existing structure.   Here we used the same principles but placed the posts at 6m (20ft) intervals without the use of a dropper between them and found it to be just as effective.    The corners were braced in a similar way.

The next job was to lay wire mesh on the ground before we got to the next stage of stringing support wires through all the posts.     Don’t put the support wire in first or you’ll probably end up decapitating yourself on them whilst laying the foot wire.       For the foot wire we used 32mm (11/4”) x 1800mm (6ft) chicken wire flat on the ground with equal amounts inside and out.    When you get to each post, (remember we were unable to put the foot-wire down before installing the posts because of the existing concrete posts) I found the best way was to cut the mesh halfway through, lay it down and the re-knit it. This means working on both side of the fence so you will need to check with your neighbours before you embark upon this exercise.  In fact, that would probably be a good idea right at the very beginning of your project, before you start anything. 

The mesh we used for the bottom 600mm (2ft) was a heavy gauge 32mm (11/4”) chicken wire and the remaining 1800mm (6ft) was a light gauge 50mm (2”) chicken wire (see figure 1.).     This chicken wire was hog-ringed to the straight wires and the existing sheep and lamb fence for support.    The resulting fence is ‘sloppy’ which is something we were aiming for, because if an animal runs into it, it will give, and nine times out of ten the animal will be uninjured, but if you have a heavy mesh (e.g. cyclone) there is a better than even chance you will end up with an animal that has a broken neck or back or some other unpleasant injury.

Figure 1

Ok, so now we have the foot wire laid out around the entire boundary, but you don’t have to do it this way if it is not practical, you can do one side at a time if you prefer.Then you can run the straight wires through the posts and fix at each corner.    You will find the use of a wire strainer very useful at this point.    These can be expensive but worth their weight in gold and you will always have it for other jobs in the future.   It is a very handy tool to keep by you and you will never regret the outlay.

Figure 2
Barbed staples used for attaching fencing materials to permapine posts and rails

Now you can start to hang the mesh which is a simple matter of fixing one end to a corner post by using galvanised barbed staples and then hogring the mesh to the straight wires.  (See Figures 2 & 3)And that is really all there is to it except that the addition of and electric fence will ensure you will keep out cats.    The foot wire will generally stop foxes and rabbits (they haven’t the brains to walk back a couple of feet and then start digging) and the sloppiness of the fence will also stop cats climbing it, but there is still the posts to consider.    Cats will have no trouble running up an eight foot fence post.

Figure 3
Fence line showing the method of attaching the mesh to the strainer wire with hogrings

Figure 4 shows a couple of options for the electric fence.    The first shows the fence with the addition of a top overhang to which you can attach the ‘hot wire’ on the outside and the other (which is the way we adopted) shows no overhang but a hot wire on the top of the fence and two, one close to the ground and another close to the top, also on the outside.  

Figure 4
Fence profiles

We have since built a second fence in this style but it was created from scratch instead of utilising an existing fence. The only real difference was that we measured out the boundary first and then used stringlines and put a marker at each point where we intending to put a post.    In this case the posts were at 6m intervals (3m at the corners) with no dropper and as mentioned earlier, we have found that they both work very well, are comparatively cost effective and will serve you well for many years without a great deal of attention.    Tip: When bracing the corners do NOT put the horizontal poles as high as shown in figure 5.    They should be about half way down the verticals.   This had the effect of pulling the corner post out of the ground when tightening up the top strainer wire and the corner diagonals.

Figure 5
Fence line at a corner showing the horizontal bracing with poles. There is also diagonal bracing with wires although not visible in this photograph.

Before finishing up on this section I would like to add a small word of caution.    When building this type of fence have some consideration for any wild creatures in your area.    We found with the second of these fences we built, much to our anguish and dismay, that the mesh of the bottom 600mm (2ft) was a death trap for the Shingleback Skink (Tiliqua rugosa), (or Stumpys or Sleepy Lizards) – they have numerous common names (see Figure 6).    They would try to squeeze through the mesh and be able to get their head through, but not their body and then find that they could not ‘reverse up’ because of their large scales and angular shaped head.   This problem is easily overcome by using a much smaller or larger mesh.   In our case, larger was not an option, as young Potoroos and Bettongs would have been able to squeeze through.

Figure 6
Shingleback Skink
(Tiliqua rugosa)

Internal Paraphernalia

I thought perhaps that this point, before I start to describe the building of wombat enclosures, I would touch upon some of the internal paraphernalia connected with macropod enclosures.

There are really only a couple of issues involved, one is food and water, the other is shelter. 

For food containers we have utilised old metal laundry troughs which have had most of their supports removed so that the animals can reach the contents comfortably.  For a water source we have used a couple of things, firstly a square or rectangular plastic trough similar to those often found in the fishing industry for transporting fish.  Secondly, we have used old baths.  Baths have a problem, in as much as they are very dangerous pieces of equipment for small creatures.  Animals like Bettongs or Potoroos for example have a habit of hopping onto the side for a drink and falling in. This can also happen to wild birds and if some provision is not made for these creatures to be able to get out, they will drown.  To that end, we line all our baths with wire mesh and since doing this we have not had a single fatality, either captive or wild.  You can use any old bits of wire you've got laying around the place for this purpose as long as you make sure it goes well below water level and right over the sides of that the bath.

Figure 7
Kangaroo shelter showing feed bins and gutter system

The kangaroo shelter shown in figure 7 is a very simply built structure using permapine poles for the supports, 'C' channel for cross members and second-hand corrugated iron for the roof and back.  An old water tank, cut in half, was used for wind protection at either end.

Another use for these old water tank halves, if laid with the cut side to the ground, could be as wallaby shelters.  If you do this however, please be sure to cover them with something so that they do not become a hot box in the summer.  Despite all the trouble we went to, to build this kangaroo shelter, they very rarely use it and much prefer to lay about in the shade under the trees.  Its main purpose is in keeping their food dry and of course the animals do use it when feeding. 

If you look closely you will also notice that provision is made to collect water from the roof of this structure.  Guttering is becoming a very expensive commodity these days and the system used here is a comparatively cheap way around the problem.  This gutter is made very simply from two lengths of 90mm stormwater pipe cut lengthwise with an angle grinder.   This is then slid over the end of the corrugated iron roof and screwed down from the top.    This has an added advantage in that it tends to flatten out on the top and stops leaves and other rubbish running into the gutter also it tends to push the bulk of the section to the underside of the roof making plenty of capacity for the water flow.

A.  Suitable for all wombat species

As mentioned earlier, the housing of wombats needs special care, the basics of which were covered in part 3 of this diatribe.    However this section covers only enclosures appropriate to the Southern Hairy-nosed Wombat (Lasiorhinus latifrons) (and would also be quite adequate for the Northern Hairy-nosed Wombat (Lasiorhinus krefftii) should they ever become available, which, at this point in time, is highly unlikely).    The Common Wombat (Vombatus ursinus) will be covered later in the article.

Dens or Sleeping Chambers

These can be any shape you like or whatever fits into your location, but the following items should, if possible, be included in your design. 

a.            Two or more entry tunnels.
b.            More than one sleeping chamber per animal.
c.            Do not make the sleeping chambers too large.
d.            Allow access to the sleeping chambers from
outside.
e.            Concrete floor with reinforcing mesh.
f.             Well insulated.
g.            Use chew and scratch resistant materials. 

Figure 8
My first attempt at a wombat den showing the two stone covered entrance tunnels at either side of the covered overhang.   The logs under the overhang are bolted together to make an access door.

I have used several different methods to build wombat dens but only two in building their enclosures.     Up to the time of writing I have built sixteen enclosures and seventeen dens.      I do not intend to give you a ‘blow by blow’ description of each of these, as the basic principles have been the same for all of them, however, I will endeavour to describe the different  building techniques.

My first wombat den was actually a converted wallaby shelter (see figure 8) and the construction went something like the following:-

The wallaby shelter was a small three sided affair with an area of approximately 2.5m x 1.5m and was on sloping ground.    My first task was to remove the shelter and dig out the area to make it level then built a framework of permapine logs to the outside of which I nailed galvanised corrugated iron to the back, sides and top, leaving the front open to allow access for working on the inside.     To the inside I nailed lengths of timber (old pallet rails) which then gave me a gap, the thickness of the permapine posts between the iron and the rails.        This I packed tightly with straw, the idea being to insulate the whole structure to help keep it warm in winter and cool in summer.      All the material I had dug out from the floor area I heaped up against the back and over the top to give the appearance of a grassy mound rather than a tin shed.     Unfortunately I did not have enough material to cover the sides as well, so I piled up a heap of rocks and one side and fixed a row of short off cuts of permapine logs on the other which gave it the appearance of a small fence disappearing into the ground.

The floor of the den was covered with a heavy steel reinforcing mesh to prevent the animals from digging within the den.        I would recommend a reasonably strong mesh for this purpose, something like concrete reinforcing mesh only with smaller squares.        I managed to get hold of some obsolete double bed spring grids (the things that bed springs are attached to inside a bed base) which were ideal, but failing this, probably the best  material would be galvanised weldmesh about 100 x 100 x minimum 2.5mm gauge (but preferably heavier).    This was laid over the entire floor area of the den and then covered with about 150mm (6") of washed sand (not builders sand) and then about a foot of straw.     I spread two full bales of hay over the floor of the den as bedding and then placed another three bales inside the den in one piece, (with the twine removed) and let our wombat do what she liked with them.     They were all soon totally dismembered and spread out all over the place, most of it pushed out through the tunnel entrances and into the enclosure.

This den, and the second, were both originally constructed in the late 1980’s and have since had concrete floors added.   The first was also divided through the centre to make two smaller chambers instead of one big one.     The main reason these dens have since been converted to concrete floors, is that we found the animals would dig out the soil from below the wire mesh, which means they are eventually sleeping on a grid with nothing but air around them.    We lost an animal (as in died) due to a urinary tract infection from the second of these enclosures some years ago and I am convinced, although there is no evidence to support my theory, that this animal died through catching a chill from sleeping in an area where air could circulate around his entire body; thereby leaving him vulnerable to the first infection that came along.

The front of the den is a little more complex (see figure 8).     This I arranged into two halves, one half having a fixed front and the other half arranged into a hinged door to enable me to gain access for cleaning purposes.     The fixed part of the front had a hole at ground level large enough for a fully-grown wombat to get through.    From this hole I placed a sheet of galvanised corrugated iron folded lengthwise into the shape of an upside down U and covered it with soil, rocks, turf etc to give the effect of a tunnel entrance to the den.      This tunnel idea was in fact an afterthought but was accepted by our wombat with grateful delight.    I would mention here that I was not particularly happy with the lining of this tunnel being made of corrugated iron (there is always the potential for the animals to injure themselves on the ends) although it never seemed to present us with any problem.    I would have preferred something like a concrete sewer pipe but was unfortunately unable to obtain one at the time.

The second den we built was basically the same as the first except the internal dimensions were only 1.5m (5ft) x 1.5m (5ft) and had a shelter over it to give protection from rain and sun (a bit like a carport - or wombatport if you like!).     Another difference was that the access door was outside the enclosure to enable me to get inside the den without having to go into the run.     This turned out to be a real bonus as the animal that occupied that enclosures was a real horror – he would have had your leg off at the knee given half a chance!

The third den we built was by far the most satisfactory.    It was constructed under a circumstance where I was able to take advantage of an existing situation and is not something that is likely to be repeatable easily.    I would go as far as to say that most people would probably not be able to copy this idea but if you can it works really well.    

Basically it was the pit under the garage floor converted to a wombat den.    Actually, that is not entirely true, as the pit was not there in the first place.    When we purchased our property in the Adelaide Hills, the concrete floor of the garage had been cut ready for the construction of a pit; but that was as far as the previous owners had got.    We just completed the process but turned it into a wombat den instead of a service pit.  

The den consisted of three chambers, a tunnel in and a tunnel out which were at opposite ends of the complex.    The floor (of the den) was concreted (I wasn’t going to fall into that trap again) with sheet steel for the sides.    This den was reasonably easy to make and, in my opinion, is about as good as it gets as far as a home for a wombat is concerned.     It was cool in summer, warm in winter and had very easy access from inside the garage.    The roof (or access) to the den was made from 50mm (2”) thick laminated particle board and was hinged in two halves so that it could be lifted for inspection purposes.   One of these halves had a clear panel under it so the animals inside could be observed without disturbing them.   Unfortunately this idea turned out to be pretty useless as most of the time it was covered on the inside with a thick layer of dust created by the animals underneath.    We had a piece of old carpet which covered one end of the garage floor and included the roof of the wombat den.   This served to deaden any noise within the garage and also as you walked across the top of the den.

The fourth & fifth dens we built were an entirely different story.    These were a construction of bricks and mortar and if I am allowed to say it myself, were quite a work of art but if you are no good at brick laying, don’t attempt it.

Figure 9
Beginnings of a brickwork den.    Note single brick for the internal walls and double brick for external.
This is the ground floor of the den shown in figure 10.

They started with a basic design and were built from the ground, up.    They were designed on paper first and then built to the drawing with a few small modifications along the way.        The design is really only limited by your imagination and the space available to you.    Again, the main points to bear in mind, are to have more than one entrance/exit and do not be tempted to make them too large.   We found that our animals spurned all the dens with large compartments in favour of the smaller ones – maybe it is a security thing?    If I have to give you a size I would say do not make the internal dimensions more than 1.2m (4ft) x 1.2(4ft) and if you recall the first den we built – that was originally 1.5m (5ft) x 2.5m (8ft) which we eventually divided into two and that housed two animals.    Even then they preferred to sleep together in one or other of the two, now much smaller, chambers.

These brick constructions were started very much as you would a conventional building, i.e. with an excavated site to the pre-drawn size and shape; then boarding up and pouring a concrete slab with reinforcing mesh, (a good opportunity to get rid of any old bits of wire, steel, old bike frames or any old metal or hardcore rubbish due for the tip) on to which you would build your brick walls.   Use single brick for the internal walls and double cavity brick for external walls.    Not too much height is necessary (the average Southern Hairy-nosed Wombat (Lasiorhinus latifrons) burrow in the wild is only about 300mm (1ft) diameter and the sleeping chambers only 500mm (1’8”) high)1.    The only reason for any extra height is to give yourself easy access to the den or unless, like figure 10, it turns out to be a very complicated two storey affair.    We made ours usually five, six or even seven bricks high depending on the size of the brick and wether the bricks were laid flat or on edge.    Tip: if you use bricks on edge you will use a lot less.

Figure 10.
Completed den showing the rendered finish.
I went a bit overboard with this one and ended as a two story
complex, which explains its apparent excessive height.

Once you have the walls in place they will then need to be rendered on both sides.    There are a number of reasons for this.   To smooth out any sharp edges on which the animals may damage themselves, to assist in the insulating properties of the brickwork and also lets not forget beautification.    It also means you can use any old ‘daggy’ second-hand bricks.    It is probably also a good idea to position the dens in such a way that they get the maximum amount of shade in summer to alleviate the possibility of the brickwork soaking up the sunshine and radiating the heat inwards at night.    This is also the reason you are using double cavity brickwork for the external walls.

Now you have the walls in place and rendered, you can start on the roof.    However, if you prefer, you can leave the rendering of the outside of the walls until you have the roof in place.   It’s entirely up to you.

The roof is a poured concrete slab using lost formwork.    (I can hear you puffing and panting already)!!    This was a lot of hard physical work but well worth it in the long run.      For formwork we used the sides of an old defunct above ground swimming pool.     This was cut up with a pair of tinsnips into suitable sized pieces which were then laid across the walls but leaving a small amount of wall showing at each edge.    This was so we could lay another layer of bricks around the perimeter that would attach themselves to the walls below and act as a barrier for the concrete when poured.     Some of the distances between walls, especially over the sleeping chambers, were far too wide for the formwork to support the weight of the concrete without some form of assistance.   Here we used bits of old timber nailed together as a ‘T’ shape and used as supports in appropriate places.   These were knocked out after the concrete had cured and don’t forget that some sort of reinforcing mesh is essential in the roof; otherwise the whole thing could crack and collapse.

Figure 11
Wombat box

The sixth and seventh dens were only temporary affairs and not intended for long term use and basically consist of using a wombat box (see figure 11) covered with bales of hay at the back, top, sides and part of the front, and then waterproofed with sheets of corrugated iron.  

However, it is my considered opinion that, even though they do not fulfil the criteria listed at the beginning of this chapter, this form of den is an excellent way of providing emergency accommodation for an animal that may be ‘dropped’ on you out of the blue or if you have an animal that needs to be quarantined for whatever reason..     In my case these dens were provided to house two young animals at a time when we had to go away for a short while and were unable to take them with us.    These two enclosures were built in one weekend and gave me the time to construct more permanent housing without having to complete it in a hurry.

Figure 12
Stone wombat den.   Note soil on the roof in place of concrete.    The soil thickness is about 300mm (1ft).

All our other dens have been constructed using the bricks and mortar method with a couple of diversions into stone (see figure 12).    These were built without allowing us any access the sleeping chambers as they are all part of a larger system where the animals have been allowed to ‘do their own thing’ and have dug their own warren systems.        Their enclosures were constructed with exactly this scenario in mind.     We determined beforehand that if they are going to be allowed to dig their own warren systems, thereby not allowing me access to them whilst asleep (or sick), why should I go to the trouble of constructing doors to access the ‘homemade’ dens when, in time, they would probably not be using them anyway.     This turned out to be a lot closer to the truth than I could ever have imagined.    The dens we built for them were only used for as long as it took them to dig their own, which would have only been months rather than years.    In fact, it would have taken us longer to build the dens, than it did for them to abandon them.    Once the animals had their own system going our dens were ignored – and still are.

Access Doors

Figure 13
Access doors with viewing windows underneath the central flap.    Note the water tank on top of the den – this was an added bonus as it helped to keep the den at a constant temperature.

The access doors of for these dens were manufactured from two inch thick laminated particle board lined with metal sheet on the inside to prevent them being destroyed through chewing and scratching.  The door frames were welded up to the required size using angle iron and were cemented into the walls at the time the bricks were being laid.  The door hinges had previously been welded into the appropriate position and the doors presented to the frames to make sure that everything worked properly before installation.

Some of these doors were quite complicated affairs (see figure 13) incorporating small windows that had flaps to keep out the light.  The idea of these windows was so we could 'spy' on the animals without disturbing them.  Unfortunately, as with the den under the garage floor, these windows would become covered in dust from the inside and therefore totally useless.

Cont’d Part 5

Back to Part 3

Bennett's Wallaby
Juvenile NT Brushtail Possum
Swamp Wallaby
Golden Brushtail Possum
Red Kangaroos
Yellow-footed Rock-wallabies
Baby Squirrel Glider
Sugar Glider
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