The Feral Sheep of Campbell Island

A Dissertation by Bill Regnault
Former Director of Wool Studies, Massey University

Introduction

      In the early 1970s Ministry of Agriculture and Fisheries (MAF) scientists were looking at the various populations of feral sheep in New Zealand and had collected small groups of animals for further study. Coincidentally with this, the then Department of Lands and Survey announced that over the summer of 1975/76, it was to sponsor a scientific expedition to Campbell Island, home of by far the greatest feral flock in New Zealand. This gave MAF the opportunity to inspect these sheep and if they were found to pose no bio-security risk, to recover some. At the same time I was involved in a study of a wool fault known as 'weak back wool' and wanted to observe its incidence in a flock not subjected to normal husbandry practices. The expedition gave me the chance to work with sheep that had had no human interference since 1930 and probably minimal attention for some years before that.

Campbell Island is 600 kilometres south of Stewart Island

Campbell Island, an unlikely habitat for sheep:

Location: Southern Ocean, latitude 52° South and about 600 kilometres south of Stewart Island (see map).
Area: 11,200 hectares
Formation: Very eroded volcano with high cliffs forming most of the perimeter and with rolling hills inland. Elevations up to 600 metres with most of the high points on or near the cliff tops.
Soil: Mainly peat of great depth in many places and constantly building. Areas, some of many hectares, of eroding peat, opened up by sheep and wind. Because of the wind, recovery is slow.
Precipitation: Rain falls on about 320 days of the year, snow on about 40. Annual rainfall averages 1400 mm. Within one day there can be rain, hail and snow interspersed with bright sunshine.
Sunshine hours: Approximately 600.
Mean Temperatures: Over year 7°. High 9°, Low 4° (Range within year -7° to 21°).
Wind: Mean wind speed 34 knots but reaching gale force on average 76 times per annum.
Flies: Flies such as those that menace sheep do not exist. The wind ensures that.
Impressions: Wind! seemingly eternal and with swirling mists hiding the hill tops two days out of three, 'clagged out' being the colloquial term. Golden brown tussock interspersed with clumps of dracophyllum scrub and here and there, bright green patches of bulbinella (Bulbinella rossii), an unpalatable fleshy plant rather similar to red hot pokers but with yellow flowers. At low levels, say up to 100 metres, sea lions are commonly encountered in the scrub while the sea elephants stick to perhaps the first 20 metres above sea level.

Rescuing Campbell Island sheep, 1975   (Photo by Bill Regnault)

      The bright white spots on the hillsides are royal albatross on their nests while clustered on the cliff tops in places are nesting colonies of tens of thousands of the lesser albatross species. Where rockfalls slope down to the sea are the rockhopper penguin colonies numbering hundreds of thousands of birds. Among all the wildlife activity the sheep carried on their normal lives, the only interaction observed being when one wandered into a sea lion breeding territory and was sent off by the resident bull, or grazing close to a nesting royal albatross and being clacked at, bill clacking being the most aggressive gesture of this great bird. A factor of unknown effect on the sheep was the presence of a predator, the skua gull. In many ways these bird give one the impression of a maritime kea; quaint, curious, tame or bold (depends how you see it) but with the difference that they are ruthless killers of anything showing any weakness. Was the fact that we saw no lame or in any way decrepit sheep due to the quality of the sheep, or was it because such sheep were quickly killed and eaten, not necessarily in that order?

Brief History of the Island and the Sheep

      Campbell Island was discovered in 1810 by a sealing captain employed by the Campbell brothers of Sydney. Over the years that followed, it was the scene of intermittent sealing and whaling expeditions, while in 1896 the island was included in the pastoral lease system that was, and still is, a feature on mainland New Zealand. It was first taken up by a Mr Gordon of Gisborne and a few hundred sheep taken down along with timber for buildings. By 1900, when he could no longer sustain the venture financially, he was bought out by Captain Tucker of the Gisborne Militia and stocking started in earnest with at least three shipments of about 1,000 sheep. Records are sketchy but it appears that one shipment was Leicester Merino cross, another Lincoln Merino cross, possibly some Merinos and one shipment was reported in the Otago Daily Times simply as '1100 sheep'.

      In all, it appears that the stocking was of about 4000 onto an island with initially copious feed available from the luxuriant growths of the palatable tussocks Chionacloa antartica and Poa foliosa as well as the very palatable megaherbs Pleurophyllum sp., Stilbocarpa polaris and Anisoteme latifolia. These plants have large leaves to make the most of the limited sunshine hours. Over the next few years, the sheep population increased to peak at about 7000-8000 around 1913 and then, as the palatable plants became eaten out, went into a steady decline as did the finances of the proposition. 1931 saw the abandonment of the flock by now down to 4000. Note too that the staff had more or less been abandoned as well, with no boat for two years and then it was the government that sent a boat to bring them off along with two seasons' wool clip. As the value of the wool fell short of the cost of the steamer, there were no wages for the men! Ownership of the sheep however still lay with the owners who had bought out Captain Tucker. They never returned, and in 1954 when the government gazetted the island as a wild life reserve, a writ was served requiring removal of the sheep with failure to comply being forfeiture to the state. The latter is what took place and in subsequent discussions on the management of the island, the term, "Those accursed sheep" cropped up regularly.

      In 1958, scientists Don Orwin and Peter Wilson did a study and a count of the sheep and came up with a figure of just under 1,000. In 1970, a coast to coast fence was built across a narrow and fortuitously central part of the island and all the sheep shot on the northern side. 1,300 were shot and there appeared to be a similar number south of the fence. A later expedition found about 2,500 sheep on the southern side and when the final cull took place, as far as I know, about 3,000 were shot. These figures led to much discussion as to what had happened between 1931 and 1958. Was there a steady decline or at some point, had the population crashed and if so, why? The crash theory makes it easier to rationalise the bounce back from 1958 to 1970. My personal belief, however, is that with the withdrawal of husbandry practices and especially shearing, the population would have had a high death rate initially; those that adapted successfully bred on to become an increasingly successful strain. When Orwin and Wilson did their count, the population was possibly already on the way back.

The Scene in 1975

      So, on to 1975 when the first group of the 1975/76 Campbell Island expedition set sail from Dunedin on RV Acheron with all our gear including ten dog chains and collars and some bags of sheep nuts to tether and feed the sheep that might be brought back. The party comprised wildlife officers, soil scientists, a botanist, entomologists, ornithologists and the sheep party which in turn comprised leader Jim Hutton of the MAF Lincoln Veterinary Diagnostic Station, parasitologist Allen Heath from Wallaceville and myself from the Wool department of Massey University. Jim's responsibility was to gather the data for the decision as to whether it was safe to repatriate sheep to the mainland, Allen's work was to assess external parasite status for the same reason and to further his own research while my objective was to look at the back wool. Much of our sampling was aided by a rifle as Jim needed to carry out full autopsies. I found it possible to run individual sheep down while the biggest single sampling came from the muster to select animals for repatriation. In all, 120 sheep were inspected and blood and wool samples taken. 50 of these had been shot and autopsies conducted. When necessary for movement within Perseverance Harbour, we had the use of the Meteorological Station boat Aurora.

      First impressions were of miserable, bedraggled animals with peat stained fleeces in various stages of shedding while here and there, the odd magnificent looking specimen, almost always a ram. As we got to know them better, we noted that even the most miserable ewes could have good vigorous lambs. Sheep that were not shedding usually carried about four and a half seasons fleece as assessed by the seasonal breaks along the staple which sometimes exceeded 300 millimetres in length. Most rams fleeces were intact while ewes that had lambs were shedding. Those ewes not shedding were invariably dry (as with no lamb) and with the matted, peat contaminated wool hanging over their genitals, could likely remain that way! Was the shedding the key to breeding success?

      Fleeces were not shed evenly or suddenly but rather by ablation, leaving a growth of new wool. The shedding started behind the ears, on the back at the withers, and on the belly (although most of the sheep seemed naturally bare bellied). This all led me to feel that 'weak back' which can be accompanied by similarly perished and seemingly finer wool on the belly and the back of the neck, was in fact nature's starting point for shedding and was so in domestic flocks before selective breeding discriminated against it. It has not been bred out entirely and given sufficient stress, weak back will still show up in even the best of our flocks. The last to go in the shedding process was a ruff of wool over the shoulder, rather like a lion's mane. Most sheep inspected were bare bellied and many were clear around the tale, self crutching as it were. As readers will be able to visualise, they looked an untidy lot.

      Jim and Allen's findings were that the sheep had no diseases or parasites that were not present on the mainland so no risk was involved in the proposed repatriation. Later laboratory work on blood and tissue samples confirmed this. A side issue was that where previously hydatids had been rife, there was now no sign of this disease, dogs being banned from 1963. Earlier, most meteorological teams had taken one or two dogs with them.

      A little anecdote on the side here: one of our autopsy sheep had very yellow fat and Jim decided to make up a microscope slide with a blood sample for a specific lab test. He got out the glass slide and poised with a drop of blood on the tip of his scalpel, remarked that his technicians at work were always very critical of his slides. "They just don't understand the difficulties of making up a slide in the field." As he said this, he deposited the drop onto the slide and immediately a big snow flake went 'splat', right on top of it! During this, as in all our autopsies, our retinue of skuas sat about five metres away waiting for a feast. We had, incidentally, become aware that if we went out without a rifle, they weren't interested in us!

Behavioural patterns

      As we went about our work, it became noticeable that the sheep were in small bands, no more than nine animals in any one band, and that we always were seeing the same animals in the same place no matter how much we disturbed them. The bands were either all male or very obviously family groups which seemed to be led by the oldest ewe. One band had a ewe with two lambs, one quite young and the other looking to be maybe eight to ten months old. In these bands there could be male lambs but no older males. The male bands were of mixed age, again up to a maximum of nine in number but at the particular time of year, no adolescent males; these were seen singly or as pairs or trios, suggesting that they had recently left or somehow been evicted from the family, and were linking up with others in similar plight. Maybe this, from some other time and place, is the origin of the saying, "Wandering like a lost sheep"! It would have been fascinating to have had a full year to observe the dynamics of such a population. There were so many questions; How are the young males moved out of the family? Does the same home range serve all year? How do the rams distribute themselves come tupping time? There must be a main tupping time although the breeding period is obviously quite spread. Then there was the situation in the vast basin between Mounts Paris and Yvon Villarceau in the west and Dumas and Menir to the east in which not a single female sheep was sighted; a thousand hectare exclusive male club? So many questions!

      As time went by I became more and more fascinated with observing sheep as animals in their own right and when opportune, went out on my own to study them. They were very much 'home range' animals and were loath to move out of familiar territory. On some of the more favourable country, home ranges overlapped and what looked like a mob broke up into individual bands when disturbed, each band filing off to their own hideaway in the scrub. On one instance, we came over a ridge and saw in a clearing below us, a family band grazing. Two lambs were up on a little knoll. Almost immediately we were sighted by the old ewe who trotted up onto the knoll and around the lambs which followed her back down. The whole group then followed her into the scrub. Another instance of the home range thing was that there were places where quite good pasture close to a band's rather sparse home range was not exploited.

      In 1975, the pasture was mainly a hard tussock, Poa Littoralis, and a variety of sedges with some English grasses in favoured spots. Two variaties of Dracophyllum, (scoparium and longifolium), were the major scrub species while the shrub Mysine divaricata was common as was a hard fern Polystichum vestitum. Autopsies revealed stomach lesions which in part could be explained by the presence of mysine and polystichum leaves and twig pieces. Grazing the hard tussock had its effect on the teeth as the sheep seemed to wrench it off and the continual wrenching drew the teeth forward giving the impression of overshot jaw. It was noticeable that on the north (sheep free) side of the fence, the megaherbs were starting a comeback.

The Sheep Themselves

      As would be guessed by the original breeding, the sheep exhibited characteristics of the mainland 'New Zealand Halfbred' but with some variations. Male/female ratios were roughly 50/50 with just under 80% of the males fully horned; many ewes carried small horns or skurrs. The sheep appeared a little longer in the leg and held their heads higher than their mainland counterparts. The back wool was usually quite badly weathered.

      Teeth: Defining age was difficult as once the full mouth stage had been reached, one had no way of telling actual years. (Subsequent work on the annular rings of sectioned teeth indicated a maximum of 11 years but then, what about those that no longer had teeth!). Grazing was a full time occupation and seemed to continue from first light into dark which at the particular time of year, was from about 4.00 a.m. to 11.00 p.m. In times of hostile weather (on one occasion, 2° and snowing), the sheep merely moved to the lower level of their range, turned their backsides to the wind and carried on. The impression was of a need of continual stoking to maintain strength and body heat.

      The effect of grazing on hard tussock was apparent as indicted by this extract from the official report: "All the sample sheep were inspected for deviations from what would be considered acceptable in domestic flocks. In no case was a malformed jaw seen but it does appear that the constant wrenching off of the tough vegetation draws the incisors forward, gradually opening a gap between them and the upper jaw pad. This appears to have no effect on grazing ability on the long feed available; there is little grazing available close to the ground. The gaps between pad and teeth were measured and in general did not exist in one year old sheep but averaged one millimetre in two and three year olds and two millimetres for five year and older animals. The greatest gap was 7.5 mm measured on a ram in this category."

Campbell Island sheep, just shorn, 1975   (Photo by Bill Regnault)

      Feet: Again quoting from the report, "Many sheep had long, over-grown hooves, to be expected where they graze on soft earth and were not subject to wear. No lameness was seen nor any noticeable deformities. This observation may not be entirely significant however because the extremely predatory skua gull may quickly dispose of animal that show any weakness or inability." Footrot was not present in the sheep.

      Body weights: Of those weighed, ewes ranged from hoggets at 20kg to 58.5 for a barren ewe and rams at 65+. Note; we weighed in a sling with a spring balance hung from a length of pipe supported on our shoulders. At 65kg, our feet sank into the peat and we couldn't get the animal fully off the ground.

      The wool was from 18 microns to 32 with most in the range 23 to 29. At every opportunity sheep were shorn dead or alive and the fleeces weighed. Fleece weights were very low, mean annual production of greasy wool being 1.3 kg for ewes and 1.8 for rams. Skin sections were recovered for measurement of the ratio of secondary to primary follicles (S/P ratio), secondary fibres being the finer undercoat fibres and primaries the longer and usually coarser fibres. These can be observed easily by parting the coat of say, an Alsatian dog but with the sheep's fleece the difference is more subtle and ratios can only be established by identifying the follicles under a projection microscope. The ratios found were between 4:1 and 5:1 as against 10:1 to 12:1 common on current halfbred flocks. This suggests when survival without husbandry became the main selection pressure, the strain that emerged had successfully reduced its fleece weight to that which was sufficient for the animals' well-being. One way of achieving this was reduction in the S/P ratio and thus a reduction in the density of the fleece in terms of fibres per square centimetre. This appears common in feral populations and a flow-on effect, noted in most feral flocks, is an increase in the degree of fibre crimping which gives a more springy and compact fleece. Hence one assumes, better insulating qualities without the burden of a heavy fleece, especially important when that fleece will be wet most of the time. Three percent of the sheep had coloured fleeces, usually dark grey/brown but with a light saddle. As this percentage exceeded the norm at the time the island was stocked, we may have been seeing the start of a trend, noting that the Pitt Island and Arapawa sheep populations went to roughly 90% coloured over a period of 130 years. The Campbells had been feral for 45 years at the time of this exercise.

      Jim and Allen had found the sheep to have no diseases or parasites not present on the mainland and on the basis of their radioed reports, it was confirmed that ten sheep should be selected for MAF. This was planned for late November and as it turned out, was on the 28th, election day, 1975. As I was the only one present with experience in handling sheep in the great outdoors, I drew the responsibility for handling the muster with all the scientific party assisting. Three days before, the party had been fully briefed on the topography we were to muster and the situations we would likely encounter, then it was standby till a favourable day. The muster area along a ridge about 300 metres high, was a bit over two kilometres long, a little over a kilometre wide and ending against the island's dividing fence where we had constructed a lead-in wing and a pen. This was with materials from a 1970 RNZAF Hercules airdrop pallet that had skidded into a gully when the materials for the fence were delivered and it involved a long uphill trek with posts and pallet boards lashed to our packs. On Campbell Island, to get anywhere you walk; to shift materials, you put them in or on your pack and you walk.

The great muster

      On the west side of the ridge the first portion was on a slope down to Northwest Bay and then along cliff tops to the fence. On the eastern side, it was along a relatively even slope. Estimates and partial counts indicted that we could expect 200 to 250 sheep in the selected area. Two days went by after the briefing with unsatisfactory weather, two days on which I set out early with a radio to evaluate and report back on chances, two days of leisurely watching the sheep and lunching with an albatross just below the cloud base with most of our muster zone clagged out. The third morning started clear and it was all on. No dogs, just 10 scientists equipped with whistles. Dogs had been banned since 1963, ending a long tradition with the meteorological teams and no exception was made for us.

The team was as follows:
      Trevor Crosby, entomologist, Auckland
      Allen Heath, parasitologist, Wallaceville
      Jim Hutton, MAF diagnostic vet, Lincoln
      Norm Judd, expedition leader, Lands and Survey Department
      Brenda May, entomologist, Auckland
      Colin Meurk, botanist, Dunedin
      Bill Regnault, Wool lecturer, Palmerston North
      Chris Robertson, Wildlife, Wellington
      Rodney Russ, Wildlife, Wellington
      Gerry van Tets, ornithologist, Canberra

      Chris was nominated as second in command and group leader of the eastern slope. I with my four helpers would take the long drive along the top and west side of the ridge. Chris with his four would drive up the more gentle and more highly populated east side. He and I had walkie-talkie radios; our watches were synchronised and we would talk every fifteen minutes. So much for planning; we didn't achieve contact for 2½ hours and when we did, it went like this: "Hello Chris, I'm receiving you at last. Where are you?" "Don't know, probably 2 k east of the fence and I'm just nearing the top of a hill, might be able to see something, this damn clag keeps coming and going. Over to you." "I'm near the top of a hill too, might spot you. Over and out." I lowered the radio and looked up; Chris was just appearing from over the crest about 15 metres away. So much for technology!

      For a start the muster went smoothly, sheep moved freely up towards the top of the ridge and along the ridge but as groups came to the those invisible boundaries of their home ranges, more and more broke back and when they did, they really did. Everyone would have had their stories, here's a couple of mine. A big ram broke and came full tilt straight toward me. No shouting or waving of arms would make him deviate so at the last moment I side-stepped and then rugby tackled him as he passed. This was very satisfying but what could I do with him now except let him go? Further on along a ledge with the cliff edge on one side and a high bank on the other, a ewe broke back and also came straight at me. This time I didn't mess round, I flattened myself against the bank and wished her well as she passed. At one point we reckoned that we had had over 250 sheep moving up and along the ridge; the number we penned was 58! As it turned out, this was more than enough.

      We had the 58 sheep and lambs in the pen just below the crest of the Dumas/St. Col ridge at about 1.00 p.m. The impression was of imposing looking rams, very tatty ewes and magnificent lambs. It appeared that the ewes did their lambs very well but at great cost to themselves. The day had turned nasty with intermittent rain, sun, clag and sleet forcing us in the end to turn the sheep loose for their sakes and our own. In between, we first selected the ten for MAF, picking what looked like sound healthy animals and taking care not to include any aged ones (we were to learn later that ages of 11 years were not uncommon). Four males comprised a hogget, a 2 tooth, a 4th and a 6th. while the females were three hoggets, one of which had reared a lamb, two 2ths, and two 6ths.We took wool samples from them all the sheep and blood samples from a further 34, slaughtered three for autopsies and shore several for fleece weights. When the fleeces had been weighed they were tipped off the calico weighing sheet to be immediately torn apart by the skuas expecting meat in there somewhere.

      The ten sheep for MAF were taken from the pen and tethered to the fence with dog collars and chains, a logical way to hold them while completing the other tasks. Right? Wrong! Logical enough in an office in Wellington but not on Campbell Island. Immediately we turned our backs on them, the skuas swept in, some actually alighting on sheep and preparing to make a meal, proving once more how the presence of predators can change the rules. It took Brenda full time to protect the sheep from these birds.

      As conditions deteriorated further, a halt was called to the sampling, the sheep turned out and the business of getting the captives back to base taken in hand. Lead them? drag them? carry them? After a bit of messing round trying the first two, it was decided to carry them one at a time up over the ridge and down the fence to 'Aurora', the Met base boat. The carry was about two kilometres and proved as much a psychological test as a physical one. At the pen was help to get the sheep onto the shoulders but then one was on one's own with an increasing longing to put the load down for a spell but knowing that once down, it would almost certainly be impossible re-shoulder it. No trouble to Norm, our expedition leader and ex the SAS. Norm set off first with the biggest ram and in no time was back for another. That first ram which weighed in at 65 kg became known as 'Big Norm'. Once all were down, we chugged the last couple of kilometres round to the base, unloaded and tethered the sheep, set a skua and sea lion guard (the lions were not hostile, they just lumbered about being a nuisance) and I set to work gathering grass to feed them. All these sheep were subsequently named, mostly with the name of their carrier or a variation. Thus we had Allena, Trevina, Christine etc. Unfortunately, one of the sheep died after the sheep group had left and before the frigate pick up. This was replaced by a well grown ram lamb but selected probably on the basis of the most easy to capture or transport.

      When it became clear that because of the skuas and young sea lions, tethering was not an option back at base either, we annexed some timber from the Met. workshops and built a pen. Naturally the sheep did not take to eating sheep nuts straight off and we spent quite a bit of time gathering feed. The sheep spent even more time coping with eating it as they were so conditioned to wrenching their food off. Presented to them loose, they continued the wrenching action and threw quite a lot over their backs. Colin unwittingly solved this problem for us. He suggested to me that since we had to gather food until we succeeded in weaning them onto nuts, we could do some palatability trials on remnants of the original ground cover now existing only on bluffs inaccessible to sheep. "Why not gather some of these species and offer the sheep along with their current diet and record their preferences?" This made sense to me so Colin and I were off in Aurora down the harbour to a craggy point where we had observed some of the particular species growing out of reach of sheep (and nearly out of reach of man!). We harvested a supply and made up little bundles of each were made up and along with similar bundles of their normal diet and hung at random around the rails of the pen. Colin and I took it in turn to watch and record. It proved quite clearly the truth of the beliefs about palatability. The fact that this food was tied in bundles also meant that the sheep had to wrench it free and they coped much better with it in this form. The species concerned were two tussocks Chionacloa antartica and Poa foliosa plus the megaherbs Pleurophyllum speciosum, Anisotome latifolia (with a distinct aniseed flavour) and the so-called polar cabbage, Stilbocarpa polaris. These are all magnificent plants to see growing and the megaherbs in flower are spectacular. For the particular exercise the sheep were also offered their more usual diet of hard tussock and hard fern but these were neglected in favour of the others. Nuts were always available and one by one, the sheep converted to this strange form of food. In about three weeks, we had the sheep onto a diet of nuts but continued to supplement with herbage.

      The sheep group left the Island just before Christmas and one of my last tasks was to shear the sheep in response to a request radioed from MAF and which also asked that they be dipped. No chance of that; we had no dipping materials. The sheep did carry a population of sheep ked, often wrongly described as 'ticks' and we were at times unpopular when someone found a ked on their clothes or body. They were not placated by our explanation that these were host specific and could survive no more than three days on human blood. At the conclusion of the expedition in March, the remaining expedition members and the sheep were brought to New Zealand on a navy frigate, the sheep going on to MAF Whatawhata for further study.

Epilogue: In the early 1980s, a further fence was built from the harbour head to the south coast and the sheep on the south east sector shot while the late 1980s saw the last of the sheep eliminated. I personally had mixed feelings about this for while I admired the sheep, I could not defend the damage they were doing as their numbers continued to rise despite the adverse conditions. Of the several thousand, today only the descendants of our ten to represent this strain. Like other feral populations, these sheep had developed into a distinct genetic strain, one facet of which I believe, is resistance to footrot. Maintaining these in a gene pool was, and no doubt still is difficult, as can be exemplified by a remark made by a former Minister of Agriculture who was visiting Massey University to discuss research funding, "Of course, you won't be messing about with any of these funny sheep."   Thank goodness for the Rare Breeds Conservation Society.

Acknowledgements:

     My colleagues of 1975
     Lands and Survey report of 1975/76 expedition
     Campbell Island - A History by I. S. Kerr.

This article – with extra illustrations – was first published in Rare Breeds NewZ in 2003.