2015 status Cape Atholl muskoxen (Ovibos moschatus) Thule region Greenland. Technical Report No. 96

2015 status Cape Atholl Muskoxen ( Ovibos moschatus ) Thule region Greenland T Te ec ch hn ni ic ca al l R Re ep po or rt t n no o. . 9 96 6, , 2 20 01 16 6 G Gr re ee en nl la an nd d I In ns st ti it tu ut te e o of f N Na at tu ur ra al l R Re es so ou ur rc ce es s 2 Title: 2015 status Cape Atholl muskoxen ( Ovibos moschatus ) Thule region Greenland Authors: Christine Cuyler1, Kasim S. Virk2, Thomas B. Clausen2 and Flemming H. Jensen2 1Greenland Institute of Natural Resources, P.O. Box 570, 3900–Nuuk, Greenland 2SPE Box 140, 3970–Pituffik, Greenland Series: Technical Report no. 96, 2016 Date of publication: 12 February, 2016 Publisher: Greenland Institute of Natural Resources Financial support: Pituffik Citizen Council ( Pituffik Borgerråd ) Cover photo: Kasim S. Virk: Adult muskox bull, August 2015, Cape Atholl. ISBN: 87-91214-73-4 ISSN: 1397-6109 EAN: 9788791214738 Cited as: Cuyler, C., Virk, K.J., Clausen, T.B. & Jensen, F.H. 2016. 2015 status Cape Atholl muskoxen ( Ovibos moschatus ) Thule region Greenland. Greenland Institute of Natural Resources. Technical Report no. 96. 37 pp. Contact address: The report is only available in electronic format. You can download a PDF-file of the report at this homepage http://www.natur.gl/publikationer/tekniske rapporter It is possible to achieve a print of the report here: Greenland Institute of Natural Resources P.O. Box 570 DK-3900 Nuuk Greenland Phone: +299 36 12 00 Fax: +299 36 12 E-mail: [email protected] www.natur.gl 3 2015 Status Cape Atholl Muskoxen ( Ovibos moschatus ), Thule region Greenland By Christine Cuyler1, Kasim S. Virk2, Thomas B. Clausen & Flemming H. Jensen2 1Greenland Institute of Natural Resources, P.O. Box 570, 3900–Nuuk, Greenland 2 SPE Box 140, 3970–Pituffik, Greenland Technical Report no. 96, 2016 Greenland Institute of Natural Resources 4 [Empty page] 5 Table of Contents Summary ..................................................................................... 7 Resume (Danish) ........................................................................ 8 Eqikkaaneq (Greenlandic) ........................................................ 9 Introduction .............................................................................. 11 Methods ..................................................................................... 14 Results ....................................................................................... 17 Discussion ................................................................................. 18 Acknowledgements .................................................................. 24 References .................................................................................. 24 6 Figures 1. Map of the Cape Atholl area, an area of approximately 880 km2, showing Pituffik (Thule) Air Base and place names. Page 11 2. Map of the grid cells used during the 2015 aerial survey of the Cape Atholl area. Each square measures 3x3 km. Page 14 3. ATV reconnaissance route from Dundas to the coast of Cape Atholl. Route was driven one day before the aerial survey. Page 15 4. Map of the Cape Atholl 2015 survey’s 407 km continuous survey line. Page 16 5. Location of muskoxen groups observed, and number animals per group, during the 2015 aerial survey of Cape Atholl area. Page 18 6. ATV’s reconnaissance for muskoxen near the abandoned Marine Base on coast of Cape Atholl. Page 32 7. Adult muskox bull on hill side near the abandoned Marine Base at the coast of Cape Atholl. Page 32 8. A second adult muskox bull on hill side near the abandoned Marine Base at the coast of Cape Atholl. Page 33 9. A third adult muskox bull almost at the shore near the abandoned Marine Base at the coast of Cape Atholl. Page 33 10. Family group of muskoxen, adult cow, on hill side near the abandoned Marine Base at the coast of Cape Atholl. Page 34 11. At Dundas, Thomas Clausen preparing the Cessna 172 for survey. Page 34 12. View from the Cessna 172 of a typical valley with muskoxen dotted across the vegetation covered braided river plain. Page 35 13. Inside the Cessna 172 using the grid map to keep track of the flight route flown and location of muskox groups observed and their number. Page 35 14. A portion (total was 16) of the muskox group grazing in mid September near the Pituffik (Thule) Air Base’s 12th Space Warning Squadron (12 SWS ) radar facility, which is ca. 15-18 km east of air base. Page 36 Tables 1. Cape Atholl muskoxen: historical local reports indicating population growth and changing distribution since their 1986 reintroduction. Page 12 2. Historical harvest quotas and seasons for Cape Atholl muskoxen. Page 13 3. Cape Atholl, 7 September 2015 muskoxen survey, results from survey flown by fixed-wing Cessna 172. Page 17 4. Muskox survey details for continuous line transects flown 7 September 2015. Page 26 Appendices 1. Raw Data Page 26 2. 2015 local knowledge: Cape Atholl muskoxen Page 27 3. The 1986 muskoxen translocations to the Thule Avanersuaq region Page 30 4. Data sheet – Ikkinnerpaamik kisitsineq /tælling Page 31 5. Photos Page 32 7 Summary Muskoxen (Ovibos moschatus) were once indigenous to the Thule region, but were hunted to extinction in the 1800’s. In 1986, seven juvenile muskoxen were translocated to Cape Atholl, an area of approximately 880 km2 at about 76.5°N. Since then, the status of the population has only been known by local reports. On 7 September 2015 the first fixed-wing aerial minimum count of the reintroduced Cape Atholl muskoxen population was done. The resulting minimum count observed 276 muskoxen, with an autumn calf percentage at 17.4%, and a density of 1.4 muskoxen per km2 on habitat below 200m elevation. Current autumn distribution demonstrates that muskoxen have established themselves throughout the Cape Atholl area reaching north to Wolstenholme Fjord (Uumaanap Kangerlua). However, most were observed in the south west portion close to the site of their 1986 release. Good foraging range, i.e., under 200m elevation, is limited to 202 km2. Given the recommended stocking density at these elevations is 1-2 muskoxen per km2, we estimate that the number of muskoxen the Cape Atholl range can sustain is approximately 300 animals. Past harvest quotas and resulting harvests have not prevented growth in muskoxen abundance. Today, Cape Atholl muskoxen exhibit increased dispersal, and there are reports that vegetation in the preferred habitat of the Maniisergat (Green Valley) is showing signs of overuse by muskoxen. Habitat conservation may be needed, since at 76.5°N the growing season for vegetation is short and regeneration slow following grazing. Today, the muskoxen are near their estimated sustainable limit for Cape Atholl. To prevent overstocking on this small sized range, we recommend the following: a quota of 30 to 50 animals over the next three to five years; licenses with muskoxen sex and age specified (following percentages in past harvests); and protection of cows and calves. Having a relatively small sustainable population in equilibrium with its range forage is preferable to steadily growing numbers on an increasingly depleted habitat. Fine tuning of future quotas and harvest seasons necessitates further minimum counts (including the calf %) and full harvest reporting. However, 8 current harvest reporting is incomplete and conducting future one-day aerial minimum counts, regardless of their frequency, hinges on the enthusiasm and financial resources of the Pituffik Citizen Council. Despite these constraints, we advise repeating minimum counts at least every three to five years to illuminate the effects of management actions taken. Resume (Danish) Moskusokser (Ovibos moschatus) var engang en del af den oprindelige fauna i Thule-regionen, men uddøde på grund af jagt i 1800-tallet. I 1986 blev syv unge moskusokser sat ud ved Kap Atholl (76.5°N) i et område på ca. 880 km2. Bestandens tilstand har siden da kun været kendt af områdets lokale. Den første minimumtælling af den re-introducerede moskusoksebestand ved Kap Atholl blev udført fra fly d. 7. september 2015. Der blev i alt observeret 276 moskusokser med en kalveandel på 17,4 % og en tæthed på 1,4 moskusokse pr. km2 i områder, der ligger lavere end 200 m.o.h. Den aktuelle efterårsudbredelse viser, at moskusokser har etableret sig i Kap Athollområdet og videre nord og østover til Wolstenholme Fjord (Uumaanap kangerlua). De fleste dyr blev dog observeret i områdets sydvestlige del i nærheden af udsætningsområdet. Områder, der ligger lavere end 200 m.o.h., giver gode græsningsarealer, men udgør kun 202 km2 af Kap Atholl-bestandens udbredelsesområde. Da den anbefalede tæthed af moskusokser på disse arealer er 1-2 individer/km2, kan Kap Atholl-området formodentlig bære ca. 300 dyr. Tidligere kvoter og fangst har ikke hindret bestanden at vokse, og i dag har moskusokserne ved Kap Atholl spredt sig så meget, at der er tegn på overgræsning ved dyrenes foretrukne arealer i Maniisergat (Grønnedal). Det er nødvendigt at beskytte græsningsarealet, fordi vækstsæsonen ved 76.5°N er kort, og regenerering af afgræsset vegetation er langsom. I dag er moskusoksebestanden ved Kap Atholl nær det estimerede bæredygtige antal, og for at forhindre nedslidning af vegetationen på det lille græsningsareal anbefaler vi følgende: En fangstkvote på 30-50 moskusokser over de næste 3-5 år; licenser med specificeret køn og alder på moskusokser (i lyset af fangstfordeling i tidligere efterårsjagter); beskyttelse af køer og kalve. 9 Det er at foretrække at have en relativt lille, stabil bestand, der er i balance med vegetationsgrundlaget, frem for en bestand i vækst på et mere og mere ødelagt vegetationsgrundlag. Fintuning af fremtidige fangstkvoter og jagtsæsoner kræver flere minimumtællinger (inklusive kalve-andel) og fuldstændig fangstrapportering. Den nuværende fangstrapportering er ufuldstændig, og fremtidige minimumtællinger fra fly afhænger af både engagement hos og bevilling fra Pituffik Borgerråd. Trods disse begrænsninger anbefaler vi, at minimumtællinger gentages mindst hvert tredje eller femte år for at belyse konsekvenserne af den forvaltning, der bliver vedtaget. Eqikkaaneq (Greenlandic) Umimmaat (Ovibos moschatus) Siornagut Avanersuarmi uumasoqatigiit akornanni uummasuusimagaluartut 1800-kkut ingerlaneranni piniarneqarnerat pissutaalluni nungutitaasimapput. Umimmaat piaqqat arfineq-marluk Kap Atholl-imut (Avannarpasissuseq 76.5°N) 880 km2-inik annertussusilimmut l986-mi nuunneqarput.Tamatuma kingorna qanoq ingerlasimanersut taamaallaat tamaani najugaqartunit ilisimaneqarpoq. Umimmaat Kap Atholl-imut eqquteqqinneqarsimasut takusat tunngavigalugit amerlassusiliinermi kisitsineq siulleq 2015-imi septemberip 7-anni pivoq. Tassani umimmaat 276-it takuneqarput, taakkunannga 17,4 %- it piaraallutik, agguaqatigiissillugulu kvadratkilometerimi ataatsimi nunami 200 meterinit pukkinnerusumi umimmaat 1,4-nik amerlassuseqarlutik. Ukiakkut taamaalinerani pissutsit takutippaat umimmaat Kap Atholl-ip eqqaaniit avannamut kangimullu Uummannap Kangerlua (Wolstenholme Fjord) tikillugu siammarsimasut. Amerlanerpaalli nunap tamatuma kujataakangiani umimmalersueqqaarfiusumi nassaassaasimapput. Nuna 200 meterinit pukkinnerusoq ivigartorfigissuuvoq, kisiannili tamanna umimmaat Kap Atholl-imut nuunneqarsimasut siammarfigisimasaanni 202 kvadratkilometeriinnarnik annertussuseqarpoq. Siunnersuutigineqartoq malillugu umimmaat tamaani ataaseq marlulluunniit kvadratkilometerimi ataatsimi uumaniartussaammata Kap Atholl-ip eqqaani umimmaat 300-t missaaniittut tamaani uumasinnaassapput. Siornatigut killilersuisarneq 16 two observers, one on either side of the airplane. All participants were local to the Pituffik (Thule) Air Base. Survey altitude varied and was about 400m ±100. Cruising flight speed was 175 km per hour. Strip width varied, although it may have been approximately 500 m to either side of the back and forth (‘spaghetti-line’) transects. Since density distribution of the muskoxen was unknown the survey was flown without dividing Cape Atholl into areas of high and low muskoxen occurrence. One day prior to the aerial survey, reconnaissance by ATV along the track route to the abandoned Marine Base located on the coast of Cape Atholl was tried to evaluate usefulness of ATV’s for counts of muskoxen in the area. It was determined that not enough terrain could be observed by ATV for this to be a useful method. Figure 4. Map of the Cape Atholl 2015 survey’s 407 km continuous survey line. The survey first flew southwest and then ran multiple ‘parallel’ lines, starting and finishing at the Dundas air strip. The aerial survey was a minimum count survey, meaning the expected result would be the minimum number of animals in the Cape Atholl area. Minimum counts are also known as ‘total’ counts, and represent a minimum estimate of the actual prevalence of the surveyed animals. Although an aerial minimum count increases area coverage and reduces ‘dead ground’ caused by topography, there will always be overlooked animals that are not included in the count. Double counting (counting the same group or individual twice) was avoided by surveying the entire Cape Atholl area in one day. 17 Muskoxen observations were given consecutive ID numbers. When a group of muskoxen was encountered, the following were recorded; grid cell position (letter + number (Fig. 2)), total number muskoxen in group (including calves), and the number of calves (age < 1 year). Calves were identified by their small body size. Results The one-day reconnaissance made it obvious that terrain and topography render ATV’s useless as a vehicle for minimum counts in autumn. Only an aerial survey would permit access to all of the area. However, ATV use resulted in several photos of muskoxen observed in the vicinity of the abandoned Marine Base on the coast of Cape Atholl (Appendix 3). The ATV reconnaissance also observed some animals limping or moving strangely and slowly. The 2015 aerial survey took about 2½ hours on one day, the 7th of September, when ca. 407 km of continuous survey line were flown (Fig. 3, Table 1). Survey altitude was approximately 1000 to 1500 feet (ca. 300-500 m). Maintained cruising speed averaged about 175 km per hour. Table 3. Cape Atholl, 7 September 2015 muskoxen survey, results from survey flown by fixed-wing Cessna 172. Parameter Cape Atholl Muskoxen Survey Continuous survey line distance (km) 407 Survey line width (km) 1 (2x 500m) Cape Atholl area (km2) 880 Survey area (km2) 407 Coverage % 46 % Altitude (m) 300-500 Air Speed (km per hr) 175 Number of muskox groups observed 29 Average group size 9.5 ± 7.0 SD Median group size 8 Max group size 30 Min group size 1 Total muskox observed 276 Calves among total 48 Minimum calf % 17.4 Group size averaged 10 individuals, with the largest group being 30 animals the smallest being solitary animals (Table 3). The latter instance occurred four 18 times. In general, groups comprised both adults and calves (Table 4). Of the 29 groups observed, only six lacked a calf or calves. Calves were found in groups across the entire survey area. Figure 5. Locations of muskoxen groups observed, and number animals per group, during the 2015 aerial survey of Cape Atholl area. Muskoxen distribution was uneven across the Cape Atholl area (Fig. 4). Of the 29 groups observed, 23 were observed within a 20 km radius of their original release site at Cape Atholl. Those 23 groups constituted 85% of the total number seen. The remaining 15% had expanded north onto ranges east of the Pituffik Thule Air Base, to a maximum distance of 40 km from the original release site. Discussion Overgrown hooves Hoof hyperplasia was first described by Burnham (1996) and Cuyler & Mølgaard (2002) as endemic among the wild Cape Atholl muskoxen population in the 1990’s. The former proposed that the overgrown hooves developed due to the lush summer pastures, e.g., those under the Maniisergat bird cliffs, which resulted in a sedentary lifestyle, while the pasture’s spongy nature provided insufficient hoof wear. However, Cuyler & Mølgaard’s (2002) anatomical observations resembled true hoof hyperplasia as exhibited in 19 mouflon sheep (Ovis orientalis) (Volmer 2003), where the hooves on all four legs are simultaneously affected, including the dew claws, which are never affected by wear and abrasion. Affected animals sampled (n=14) exhibited exemplary body fat reserves, large body size, almost no tooth wear despite advanced age and no outward signs of disease (Cuyler & Mølgaard 2002), and pathological examination of their hooves ruled out the latter (Volmer unpublished). Genetic defects were also suspected. Investigations comparing the amino-acids in the hoof keratin of overgrown hyperplasic and healthy normal hooves revealed significant differences (p = 0.003) (Volmer, Hecht & Cuyler unpublished). Further investigation will be needed to clarify the connections and mechanisms of the observed hyperplasia in muskoxen at Cape Atholl. The altitude and speed of the 2015 aerial survey did not permit close observation of the muskoxen, and no instances of overgrown hooves were seen. Further, this study’s ATV reconnaissance observed no obvious instances of hoof hyperplasia, although a few animals had difficulty walking and may have been afflicted. In contrast, 15 to 20 years ago overgrown hooves were endemic. To ascertain whether the situation is different today will require further field observations with the sole purpose of finding hyperplasia. Abundance & distribution This population began with 7 animals. The closest neighbouring population is far to the north in Inglefield Land, and given natural barriers, emigration and immigration are assumed to have been zero. On September 2015 there were a minimum of 276 muskoxen. This population has also begun spreading northward across Cap Atholl over the last decade. Since 2005 single animals began appearing in the vicinity of the Pituffik (Thule) Air Base, 2014 saw small groups, and then 2015 saw the first large mixed groups (Thorbjørn Jørgensen pers. comm.; Fig. 14). In contrast to the past, when muskoxen were typically only seen from the point of Cape Atholl and down to the Pituffik Glacier, now muskoxen can be observed along the entire coast line starting already from the Pituffik (Thule) Air Base. Local reports of increasing abundance and expansion of the Cape Atholl muskoxen population were confirmed by this survey. 20 Habitat & recommended muskoxen density Habitat conservation may be the wise path. The entire Cape Atholl area is small, about 880 km2. Specifically at this high northern latitude, however, not all of the 880 km2 is suitable muskoxen foraging habitat. Greenland studies have shown that muskoxen body size and reproduction hinge on their range’s nutritional condition and their density upon it (Olesen et al. 1994, Lyberth et al. 2007). West Greenland muskoxen are known to prefer low elevation habitat (Olesen 1993). From the Canadian arctic, studies indicate that the best muskoxen habitat is below an elevation of 200m (Thomas et al. 1981). Further that this habitat can support just 1-2 muskoxen per km2 on a year round basis, and most importantly, only if the winters are not too severe (Thomas et al. 1981). At present, this is the best estimate for a muskoxen stocking density in the high arctic. Elevations below 200m at Cape Atholl involve just 202 km2 of habitat, and the quality, quantity and availability of the forage vegetation are unknown. Using the stocking density of 1-2 muskoxen per km2 (notwithstanding extreme weather events), the current study’s density of 1.4 muskoxen may be sustainable if the habitat is good. This would suggest that a population size in the vicinity of 300 animals, or less, may be sufficient to allow forage regeneration. The annual bird guano (fertilizer) deposited under the bird cliffs in the Maniisergat Valley likely promotes conditions favourable to vegetation regeneration following grazing. This may account for the large number of muskoxen observations here and in similar nearby valleys. Conditions will not be as productive in areas with few or no bird cliffs. Alternately, it is possible that the current habitat is depleted relative to its unused condition prior to the release of muskoxen in 1986. Perhaps 300 muskoxen would now be too many for Cape Atholl. Recent local observations for the Maniisergat (Green Valley) describe willows and tundra torn up (‘ploughed’) in swathes alongside rivers, and the grass in the ‘green’ areas appearing lawn mowed and overgrazed (Thorbjørn Jørgensen, Max Franklin and Kurt Burnham pers. comm.; Appendix 5). This isolated high arctic range, of only 202 km2 forage, may be overstocked, which would be unfortunate, since abundant available nutritious vegetation is the primary foundation for a viable muskoxen population on Cape Atholl. 21 Hunter harvest & natural mortality Hunter harvesting began in 2001, and although hunter reports for each animal are mandatory, actual reports received for any one hunting season has varied from zero to almost complete. The Greenland Institute of Natural Resources is aware of unreported harvest and the shooting of entire family groups. In the 2014-2015 hunting season the quota was 15 muskoxen, but only 8 were reported killed. Full hunter reporting is important if harvest quotas are increased. Natural mortality, as opposed to hunter harvest, may result from among other things, starvation, accidents, disease, injury, predators, and in the absence of the latter, old age related factors that feed back into the first four. Mortality owing to predation by large predators (including polar bears) is suspected in the Cape Atholl area, but unknown in scope. Predation may be low because of the infrequent predator presence, owing in part to their being shot before ever making it as far south as Cape Atholl. For example a lone wolf (the first in decades and most likely originating from Canada’s Ellesmere Island) was shot January 2016 at the small settlement of Siorapaluk, which is about 160 km and two fjords to the north of Cape Atholl. Stochastic events and density dependent effects notwithstanding, while assuming an average age at death as 15 years for a natural mortality of 6-7%, and using the current total count of 276 muskoxen, then the natural adult mortality for Cape Atholl muskoxen may be in the vicinity of 16 to 19 animals annually. Trends in calf production In the 1990’s, according to local reports, calves made up 25-35% of all animals observed (Table 1) in summer. We assume these earlier observations are reliable, since anyone can pick out calves, owing to their considerably smaller size relative to other muskoxen. This study’s observed autumn 2015 calf percentage, however, was a modest 17.4%. Cape Atholl’s early values appear similar to the Kangerlussuaq muskoxen calf production (24%) observed during their initial period of herd growth (Clausen 1993), while today’s result is similar to recent declined calf production at Kangerlussuaq, (Cuyler unpublished). Perhaps Cape Atholl muskoxen are also experiencing a declining trend in calf production. If true, future calf production rates may not much exceed this study’s observed autumn 2015 calf percentage. 22 At 17.4%, calf production can be considered sufficient. Disregarding possible severe weather events for the 2015-2016 winter (e.g., abnormally deep snow, rain-on-snow, icing, thaw-refreeze), and given a maximum natural winter mortality of 19 animals, coupled with a maximum harvest totalling 15 shot dead (i.e., ignoring possible unreported poaching), the expected pre-calving population would then be about 242 muskoxen and result in a spring 2016 calf production of about 51 calves. Management implications To date there have been no studies of muskoxen grazing impacts on vegetation at Cape Atholl, or elsewhere in Greenland. Meanwhile, overgrazing at some locations has become noticeable to the casual observer (Appendix 5). There may be reason to be concerned about habitat conservation. We have only a general recommended stocking density based on studies in Canada that are over 35-years old. How well that stocking density describes when these herbivores are in equilibrium with their range’s capacity to rejuvenate at Cape Atholl is unknown. With approximately 50 new calves expected in the spring of 2016, raising the hunting quota could harvest this production and be a step towards curbing herd growth and maintaining the recommended stocking capacity. It is important to maintain a harvestable Cape Atholl muskoxen population and conserve the habitat they are dependent upon. We recommend that the 2016 hunting quota be, as a minimum, doubled to become 30 muskoxen. In light of the fact that reported harvests have often fallen short of actual quotas and may reflect low harvesting, we suggest the quota actually be increased up to 40-50 muskoxen. This number would approach annual calf recruitment, which is the “intereston-your-capital”, and thus better ensure halting further population grow. Setting a hunting quota higher than the desired number for harvesting, is one technique to achieve that goal, specifically in locations like Cape Atholl where weather conditions can prevent hunter access to the area for much of the hunting season. Given the projected calving production for 2016 and conservative estimate of mortality, a harvest of 30-50 animals annually for the next 5 years might be supportable. However, if new information emerges to indicate the development of either a much larger or smaller population, then further quota adjustment would be required. 23 If there is to be an increased quota on this relatively small population, then possible hunter harvest bias is best avoided. Calf production and genetic variability (such as it is) are priorities. Removing too many of one sex or age class could have negative impacts on the future abundance and genetic variability of this population. Here is an opportunity to let past harvests guide us. From 2001 to 2014, a total of 71 muskoxen, which included all age classes, were reported harvested on Cape Atholl (Cuyler unpublished). This total harvest included 56% adults, 48% sub-adults and 4% calves (age < 1year). The harvested sex ratio was approximately 50:50 for both adults and calf age classes. Among sub-adults, however, it was the juvenile males that were most often selected by hunters relative to juvenile females, 74% and 26% respectively within their age class. Shooting of entire family groups is not recommended. We recommend that each hunting licence stipulate a specific age-class and sex to be taken. Given this survey’s results, it is apparent that past harvest selection has provided room for population growth. Until further data is obtainable, the allocation of age/sex on licences could initially pattern itself on the percentages for harvested age and sex in the above paragraph; with the exception that protection from hunting is extended to cows with a calf-at-heel (age < 1-year) and calves. Monitoring improvements The September 2015 count provides only a ‘snap-shot’ of the minimum abundance, distribution and autumn calf recruitment for the Cape Atholl muskoxen population. Although a herd size estimate cannot be made directly from this one count owing to the unknown and variable strip width, this could be changed by either a time-series of counts or improved methods. A time-series of minimum counts would constitute a reliable index of trends, e.g., increasing, decreasing or stable herd size, while the number of calves relative to the total number observed would indicate expected future trends in abundance. Alternately, if methods were improved so that the strip width was measured and kept constant for the entire survey, then the counts could provide a simple strip width population estimate of the entire area. Further changes to methods could include replacing the present east-west orientation of transects with a north-south axis. The east-west axis is appropriate for the shape of the area surveyed. However, given our new knowledge that Cape Atholl muskoxen distribution follows a north-south gradient, which may 24 reflect an important habitat gradient, future surveys may use a north-south transect axis. Monitoring frequency Fine tuning of future quotas and harvest seasons will necessitate further minimum counts (including the calf %) and full harvest reporting. However, current harvest reporting is incomplete and conducting future one-day aerial minimum counts, regardless of their frequency, hinges on the enthusiasm and financial resources of the Pituffik Citizen Council. In a perfect world, surveys would be repeated in the same season every year or at least every second or third year. Realistically however, as a minimum, a one-day survey every three to five years is advised. Acknowledgements This survey would never have happened without the engagement of the Pituffik Citizen Council. We sincerely thank the pilot Steen Svensson and Pituffik Flying Club for providing their Cessna 172. This project was financed by the Pituffik Citizen Council, Pituffik Air Base, Greenland. Grateful thanks for ideological support from the Nordic Resource Management project 2015. We thank Wendy Loya and Lars Witting for review of the manuscript, and Gogie McCullough for proof reading. References Boertmann, D., Forchhammer, M. Olesen, C.R., Aastrup, P. and Thing, H. 1992. The Greenland muskox population status 1990. Rangifer. 12(1): 5-12. Burnham W. 1996. Progress Report 1996: Thule Greenland Project. The Peregrine Fund, 566 W. Flying Hawk Lane, Boise, Idaho 83709, USA. 10 pp. Burnham W. 1997. Progress Report 1997: High Arctic Institute Pituffik, Greenland. The Peregrine Fund, 566 W. Flying Hawk Lane, Boise, Idaho 83709, USA. Cuyler L.C. & Mølgaard H.S. 2002. Overgrown hooves from muskoxen (Ovibos moschatus) of Kangaarsuk (Cape Atholl) Northwest Greenland. Greenland Institute of Natural Resources. Technical report No. 41. 30 pp. 25 Lyberth B., Landa A., Nagy J., Loison A., Olesen C. R., Gunn A. & Forchhammer M. C. 2007. Muskoxen in the high Arctic-temporal and spatial differences in body size. Journal of Zoology. 272: 227-234. Olesen C.R. 1993. Rapid population increase in an introduced muskox population, West Greenland. Rangifer. 13(1): 27-32. Olesen C.R., Thing H. & Aastrup. 1994. Growth of wild muskoxen under two nutritional regimes in Greenland. Rangifer. 14(1): 3-10. Thomas D.C., Miller F.L., Russel R.H. and Parker G.R. 1981. The Bailey Point region and other muskox refugia in the Canadian Arctic: a short review. Arctic. 34(1): 34-36. Vibe C. 1967. Arctic animals in relation to climatic fluctuations. Meddelelser om Grønland. Kommissionen for Videnskabelige Undersøgelser i Grønland, Vol. 170 (5): Pages 153-162. Vibe C. 1971. Moskusoksen. - In: A. Nørrevang, T.J. Meyer and S. Christensen (eds.), Danmarks natur, Grønland og Færoerne. Politikens Forlag. Pages 401-404. (in Danish) Vibe C. 1981. Landpattedyr: moskusoksen. - In: A. Nørrevang and J. Lundø (eds.), Grønlands natur. Politikens Forlag. Pages 479-482. (in Danish) Vibe C. 1986. Tilbage til de gamle græsgange. Augut. Pages 6-7. (in Danish) Volmar K & Herzog A. 2003. Diagnostik, Differentialdiagnostik und Sanierungsmöglichkeiten von Klauenerkrankungen beim Muffelwild – eine Übersicht. Beitr. Jagdund Wildforschung 28: 337-344. 32 Appendix 5 Photos Figure 6. ATV’s reconnaissance for muskoxen near the abandoned Marine Base on coast of Cape Atholl. Photo Kasim Virk. Figure 7. Adult muskox bull on hill side near the abandoned Marine Base at the coast of Cape Atholl. Photo Kasim Virk. 33 Figure 8. A second adult muskox bull on hill side near the abandoned Marine Base at the coast of Cape Atholl. Photo Kasim Virk. Figure 9. A third adult muskox bull almost at the shore near the abandoned Marine Base at the coast of Cape Atholl. Photo Kasim Virk. 34 Figure 10. Family group of muskoxen, adult cow, on hill side near the abandoned Marine Base at the coast of Cape Atholl. Photo Kasim Virk. Figure 11. At Dundas, Thomas Clausen preparing the Cessna 172 for survey. Photo Kasim Virk. 35 Figure 12. View from the Cessna 172 of a typical valley with muskoxen dotted across the vegetation covered braided river plain. Photo Kasim Virk. Figure 13. Inside the Cessna 172 using the grid map to keep track of the flight route flown and location of muskox groups observed and their number. Photo Kasim Virk. 36 Figure 14. A portion (total was 16) of the muskox group grazing in mid September 2015 near the Pituffik (Thule) Air Base’s 12th Space Warning Squadron (12 SWS) radar facility, which is ca. 15-18 km east of the air base. Photo Kasim Virk. 37 [Empty page]