Mountain Goat Population Inventory Thompson Region Management Units 3-32 and July 18 20, 2005

Transcription

1 Mountain Goat Population Inventory Thompson Region Management Units 3-32 and 3-33 July 18 2, 25 Prepared for: British Columbia Conservation Foundation Prepared by: S. L. Lemke, R.P. Bio. October 25

2 SUMMARY Mountain goat sightings by LEH zone, MUs 3-32 and 3-33, July 25. Total Goats Classified Unclassified % Juvenile Average Group Size Female Kid Male Adult Goat 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon E Noel East F Truax Totals Mountain goat observations and population estimates by LEH zone, MUs 3-32 and 3-33, July 25. Total Goats Observed Additional Tracks Estimated Goats (corrected for sightability) Population Estimate (1994) Guide- Outfitter Estimate (25) 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon * E Noel East F Truax * 6 55 Totals *Corrected estimate based on total goats observed plus additional track sightings Mountain goat densities by LEH zone, MUs 3-32 and 3-33, July 25 Zone Area (km 2 ) Area searched (km 2 ) Total Goats Observed Goats/km 2 Searched (Observed) 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon E Noel East F Truax Totals ii

3 Goat sighting rates by LEH zone, MUs 3-32 and 3-33, July 25 Total Goats Search time (hrs.) Goats/hour 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon E Noel East F Truax Totals iii

4 Table of Contents SUMMARY...ii INTRODUCTION... 1 METHODS... 1 RESULTS... 2 Survey Conditions... 2 Observations and Population Estimates... 2 Densities and Sighting Rates... 3 Elevational Range of Goats Observed... 5 Additional Wildlife Sightings... 5 SURVEY COSTS... 5 DISCUSSION... 5 Population Inventory... 5 Harvest Management... 6 Management Unit Management Unit Trends in Nanny Harvest REFERENCES List of Tables Table 1. Mountain goat sightings by LEH zone, MUs 3-32 and 3-33, July Table 2. Mountain goat observations and population estimates by LEH zone, MUs 3-32 and 3-33, July Table 3. Mountain goat densities by LEH zone, MUs 3-32 and 3-33, July Table 4. Goat sighting rates by LEH zone, MUs 3-32 and 3-33, July Table 5. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, MU Table 6. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, Management Unit List of Figures Figure 1. Estimated hunter-days and LEH permits, Management Unit 3-32, Figure 2. Goat LEH permits, harvest and 5-year trends, Management Unit 3-32, Figure 4. Estimated hunter-days and LEH permits, Management Unit 3-33, Figure 5. Goat LEH permits, harvest and 5-year trends, Management Unit 3-33, Figure 6. Mountain goat harvest per unit effort, Management Unit 3-33, Figure 7. Mountain goat harvest, by sex, Management Units 3-32, Figure 8. Mountain goat harvest, by sex, Management Units 3-33, iv

5 INTRODUCTION A strong declining trend in the kill per unit effort for mountain goats in the province since 1991 has caused considerable concern among provincial and regional wildlife managers with regard to the status of goat populations (I. Hatter, pers. comm.). However, basing population trend analyses on harvest data alone is questionable. Most goat populations in the Thompson region (Region 3) have not been formally surveyed since the mid-198s. The provincial Wildlife Harvest Strategy (1996), Harper et al. (21) and Morgan (25) recommend population monitoring for this species every three to five years, and standardized inventories were recently identified as a priority for funding in BC (Ayotte 25). In the absence of up-to-date inventory data, regional wildlife managers have been obliged, in the interests of population sustainability, to formulate ultra-conservative harvest objectives and regulations. Current inventory information will provide a stronger basis for reliably estimating mountain goat populations and may reveal areas where recreational opportunities for the species can be increased or expanded. The purpose of this survey was to obtain precise population inventory data, i.e. total count and indices of productivity, for mountain goats in priority LEH goat zones in management units (MU) 3-32 and 3-33, west of the Fraser River (Appendix A). The BC Ministry of Environment provided funding for this project through the Recreational Stewardship Inventory fund. Project administration was ably provided by the British Columbia Conservation Foundation. Special thanks to K. Jackson for his enthusiasm and skilful piloting. As always, the efforts of D. Smallman in accommodating our schedule and putting the customer first are very much appreciated. Thanks to K. Bracewell for his assistance with surveys and for sharing his detailed knowledge of local goat populations. For their hospitality, thanks to S. Waterer and K. Bracewell. Thanks to M. Panian for his assistance with GIS and data management. For administrative support, thanks to D. Gibson and D. McNicol. Once again, I am grateful to D. Jury for his encouragement and guidance in all things goaty. METHODS Survey flights were conducted from a Bell 26B JetRanger helicopter, piloted by Kevin Jackson of Cariboo Chilcotin Helicopters Ltd. The aircraft was equipped with bubble windows in the rear and wedge windows in the front for increased visibility. Doug Jury (BC Ministry of Environment, Kamloops) navigated from the front left seat, classifying goats and recording flight lines and incidental wildlife sightings on 1:5, scale topographic maps. Susan Lemke (Ursus Ecological Consulting, Kamloops) observed from a rear seat, recording classifications, habitat characteristics and entering animal locations into a hand- held Garmin GPSmap 76C unit. Kevan Bracewell, the local guideoutfitter, observed from the second rear seat. Surveys were flown between 53h and 12h, and between 163h and 21h, in order to avoid the heat of midday, when goats may be less visible while bedding, and to minimize observer fatigue. Drainages were systematically flown at contours ranging between 17 and 26 m (55 85 ft). Depending on terrain and timberline, a lower contour was flown initially, usually between the 19 and 21 m level. Upper 1

6 contours were flown between 21 and 23 m, again, depending on terrain. Some areas required only one contour flight due to the narrow elevational range of suitable habitat, while the majority required two passes, and occasionally, three. In those areas requiring only a single pass, the flight contour varied with the terrain to optimize coverage of goat habitat. Air speed during searches was maintained between 9 and 11 kph. Depending on local topography, height above ground varied between 3 and 6 m. Consecutive contour flights were flown with a minimum time interval between (<3 minutes) to reduce the incidence of recounting animals moving upslope. Goats were classified as adult or kid based on body size, horn growth and facial structure, and sexed (when possible) by body and horn shape and size, presence or absence of a vulval patch or scrotal sac, or from behavioural cues, i.e. urinating posture. In many cases, classification of adult females was assumed based on close association of a juvenile. As the intent of the survey was to obtain a total count and calculate an adult/ juvenile ratio, and, considering the disturbance resulting from the increased time and proximity necessary for accurate sex classification, limited efforts were made. The identification of yearling animals was noted, although these were not included in the classification summary; these animals were grouped in the adult classes. RESULTS Survey Conditions Survey flights were initiated on the morning of 18 July, under ideal flying conditions cloudless sky and very little wind. Air temperature was 1 C. The lack of cloud cover reduced sightability somewhat by creating significant glare and shadows. These factors did not adversely affect sightability as the morning progressed, and the sun rose higher in the sky. Skies remained clear for the evening of 18 July, although winds had picked up (25 4 kph), making manoeuvring of the machine in steep terrain more difficult and dangerous. The morning of 19 July dawned clear, with light winds (~15 kph). Sun glare and shadows were still problematic, although high cirrus cloud started building midmorning. Air temperature was 5 C. High-scattered cloud and light winds, with alpine (~25 m) temperatures in the 4 C range, marked the evening effort. Clear, calm skies again provided excellent survey conditions on 2 July, both morning and evening, with a light wind picking up after 18 h. Temperatures remained in the 7 C range throughout the day. Observations and Population Estimates A total of 377 goats were seen during the survey (Table 1). Of goats sighted, 282 (75%) were adults, and 94 (25%) were kids. Seventeen (17) animals were recorded as yearlings; these were included in the adult counts (either as nannies or unclassified adults). Sixtyfive animals (17%) were unclassified as to sex, including 64 adults. Of classified adults, 182 (48%) were nannies and 36 (1%) billies. Based on well-documented sex-specific behavioural data, the majority of unclassified animals sighted in larger associations 2

7 (i.e. >6 individuals) were most likely nannies, and those in smaller groupings were billies, and were therefore, in most cases, classified as such. Thirty-two percent of goat sightings (121 animals) were recorded in Zone B of MU 3-32, with 15% (58) in Zone 3-33A, 31% (116) in 3-33B, 5% (19) in 3-33C, 15% (56) in 3-33E, and 2% (7) in 3-33F. Based on 65 unique sightings, the average group size was 6 animals, with groups ranging from single animals to the largest group (52 animals), reported in the Windy Pass area of Eldorado (Zone 3-32B). Zone 3-33D was not surveyed due to a shortage of inventory funds. Table 1. Mountain goat sightings by LEH zone, MUs 3-32 and 3-33, July 25. Total Goats Classified Unclassified % Juvenile Average Group Size Female Kid Male Adult Goat 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon E Noel East F Truax Totals Gonzalez-Voyer et al. (21) compared the number of mountain goats seen during aerial surveys to the actual number of goats in a marked population in Alberta. On average, 69.5% of the goats were seen during aerial surveys. Cichowski et al. (1994) reported similar results, suggesting that this figure may apply widely to mountain goat helicopter surveys. Using this value, the corrected population estimate for the survey area as a whole is 575 goats (Table 2). Fresh tracks were observed in Zone 3-33F; the animals thought to have made these tracks were never located, despite an extensive search. These tracks were included in the calculation of the corrected population estimate for this zone, as were several tracks recorded in 3-33C (Table 2). During survey efforts in 3-33C, 28 goats were classified outside the regional boundary in Region 2. With a series of ridges connecting McParlon Creek in Region 3 and Pebble Creek in Region 2, it is reasonable to assume that animals can and do move back and forth over the height of land between the two drainages. Combined sightings for these areas would suggest a population of approximately 7 goats. Densities and Sighting Rates Overall observed goat density was.39 goats/km 2 (Table 3). Observed goat densities were highest in 3-33B, with.88 goats/km 2. Densities in the remaining zones of MU 3-33 were.46,.22,.7 and.5 goats/km 2, respectively. Goat density in 3-32B was.3 goats/km 2. Goat sighting rates were highest in 3-33B, where 116 goats were observed in 3.3 hours of search time (35 goats/hour). The lowest sighting rate was in 3-33F at 2.9 goats/hour (Table 4). The overall sighting rate for the survey was 2.4 goats/hour. 3

8 Table 2. Mountain goat observations and population estimates by LEH zone, MUs 3-32 and 3-33, July 25. Total Goats Observed Additional Tracks Estimated Goats (corrected for sightability) Population Estimate (1994) Guide- Outfitter Estimate (25) 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon * E Noel East F Truax * 6 55 Totals *Corrected estimate based on total goats observed plus additional track sightings Table 3. Mountain goat densities by LEH zone, MUs 3-32 and 3-33, July 25 Zone Area (km 2 ) Area searched (km 2 ) Total Goats Observed Goats/km 2 Searched (Observed) 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon E Noel East F Truax Totals Table 4. Goat sighting rates by LEH zone, MUs 3-32 and 3-33, July 25 Total Goats Search time (hrs.) Goats/hour 3-32B Slim/Eldorado A Whitecap B Noel West C McParlon E Noel East F Truax Totals

9 Elevational Range of Goats Observed The average elevation of goat sightings was approximately 2225 m (73 ft), with the lowest elevation sighting at 198 m (65 feet), and the highest at 247 m (81 ft). Eighty-six percent of goats sighted were between 198 and 2375 m (65 and 78 ft). Additional Wildlife Sightings Thirteen mule deer were sighted during the survey, as well as several hoary marmots. No grizzly or black bears were observed; however, two grizzly digs were noted. SURVEY COSTS Total cost for the 25 mountain goat survey was $28,985. Helicopter charter accounted for 84% of expenditures ($24,282), with food and lodging for 2 observers and the pilot ($1,33) and contract services ($3,6) rounding out the total. DISCUSSION Population Inventory The Thompson regional wildlife management plan estimated a 1994 fall mountain goat population of approximately 54 animals in LEH goat zones 3-32B and 3-33A, B, C, E and F. This survey suggests that a minimum of 377 goats inhabit these zones, with 575 animals estimated when observations are corrected for sightability bias. The July 25 population inventory suggests that mountain goat populations inhabiting these management areas are, overall, healthy and productive, and are at least stable and may be increasing (however, see below). Kids represent 25% of the population, with a ratio of 51 kids per 1 adult females. A billy ratio of 2 per 1 nannies is considered low for lightly hunted populations; however, the tendency for the largely solitary males to inhabit sub-optimal, very rugged habitats, quite frequently with significant vegetative cover, makes observability lower for this segment of the population. This pattern may explain the low billy:nanny ratio obtained here, and the fact that many of the unclassified lone animals and pairs of goats recorded were likely billies. The kid :nanny ratio, however, indicates that there is an adequate number of billies to service these populations. The low numbers of goats recorded in Zones 3-33C and 3-33F, and the likelihood of missed goats (as evidenced by fresh track sightings), precludes definitive estimates of population size and productivity in these zones. However, current population estimates derived by wildlife managers and the local guide-outfitter are in agreement, and there is no reason to suppose that goats in these zones should fare differently than those in adjoining units, i.e. similar (contiguous) habitat and access. Repeated surveys of these areas would clarify the situation. 5

10 Weather conditions in the weeks preceding survey flights in large part determine the sightability of animals. Warm summer temperatures force goats to seek thermal cover in timber or on rocky outcrops. Occupancy of these features makes the animals much more difficult to see. The timing of surveys should be flexible enough to account for seasonal temperature patterns. Generally, surveying goats in July will avoid the trend of animals moving into thermal escape cover as the heat of summer progresses. The average temperature in Pemberton, BC, to the south of the survey area, in the two weeks preceding the 25 survey effort was 24º C. Even accounting for the cooler conditions on higher elevation goat ranges, these temperatures would certainly drive animals to seek refuge from the heat. A survey of a section of MU 3-32, conducted in mid August 1985, during an extended period of hot weather, reported 57 goats observed with a density of.16 goats/km 2. By comparison, a similar area surveyed in July 25 yielded 121 goats observed and a density of.3 goats/km 2. Further, higher total counts were reported for the 25 survey, as compared to the 1985 effort, for both the Slim Creek/Leckie Creek (western) portion of 3-32B and the (eastern) Eldorado portion. A 1996 reconnaissance flight in the Eldorado area produced a count higher than that in 1985, but lower than the present survey. Perhaps the earlier timing of the 25 effort, despite the heat, increased sightability, or the goats in this zone have been productive and their numbers now exceed the most recent (1994) estimate. The small average group size (6 animals) observed during this survey is unusual; generally, large nanny/kid maternity groups have formed or are forming at this time of year, to feed in relative safety on abundant alpine forage. Interestingly, observations of goat groups subsequent to the survey suggest that with the exception of a few areas, i.e. Eldorado and Leckie Creek (3-32B) and Sunshine Mountain (3-33E), mountain goat group size remained under 15 animals. The significance of this finding is currently unknown; the implementation of a regular series of comprehensive surveys and continued reporting from area guide-outfitters will be key in tracking trends in group size, as well as accurately identifying and evaluating trends in goat numbers and population composition. Harvest Management Management Unit 3-32 Hunter effort in MU 3-32 was increasing slightly through the late 199s (Figure 1). Although in keeping with this trend, the spike in hunter-days in 21 is most likely due to sampling error, and not indicative of a doubling in hunter effort, particularly when considering the number of LEH permits was reduced in 2, 21 and again in 22 (Figure 1). The reduction in goat harvest (Figure 2) can be attributed to this decrease in LEH opportunities. Hunter success has been relatively stable through this period, with low rates evident in 2 and 21 when permit numbers were reduced (Figure 3). Sampling error in the estimation of hunter-days is likely the cause of the high success rate calculated for Kill per unit effort now appears to be increasing slightly, which, with stable permit numbers and hunter effort (since 22), suggests a stable or increasing goat population and/or improved hunter access to goat habitats (Figure 3). 6

11 Table 5. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, MU Population Estimate (1994) Population Estimate (25) AAH (3% of 1994 population estimate) 3-Year Average Harvest (22-24) 5-Year Average Harvest (2-24) 3-32B Slim/Eldorado Estimated hunter-days 15 1 Total Resident Hunter-Days Total Resident Permits 5-year average - Hunter Days 5-year average - Permits Total permits available Figure 1. Estimated hunter-days and LEH permits, Management Unit 3-32,

12 Total Resident Permits Total Resident Harvest 5-year average - Harvest 5-year average - Permits Permits available Total goat harvest Figure 2. Goat LEH permits, harvest and 5-year trends, Management Unit 3-32, Goats harvested/hunter day Figure 3. Mountain goat harvest per unit effort, Management Unit 3-32,

13 Management Unit 3-33 Hunter-days and harvests in MU 3-33, in general, have been decreasing since the mid 199s as permit numbers have been reduced (Figures 4 and 5). Although not available on a LEH zone basis, the hunter success rate in MU 3-33, though variable, has been increasing since the mid 199s (Figure 6). This suggests that goat numbers are at least stable or are increasing, and/or goat habitat has become more accessible to hunters, through road construction or upgrading. Average harvests in Zones 3-33C are approximately 25% above, and in 3-33F well below, the respective AAHs (Table 6). Interestingly, these two zones are those in which 25 survey counts and population estimates were questionable, due, in part, to the potential for inter-regional travel by goats in 3-33C and missed goats in 3-33F. The high harvest in 3-33C (relative to the AAH) may result from more opportunities presented by a larger-than-estimated population of goats, and/or through increased access to traditional goat habitats in the Hurley River drainage. Historically, the majority of goats harvested in 3-33F have been taken in the Truax Creek drainage, where road access exists. It is possible that goats in this area have been disturbed frequently enough to alter their habitat use patterns, forcing them into less hunter-accessible areas of the zone. The low harvests in 3-33F may result from a combination of this shift in habitat use and reduced hunter effort overall south of Carpenter Lake. Indeed, all goat sightings recorded in the Truax Creek drainage during the 25 survey were well away from ground viewing sites on the road access. Table 6. Current annual allowable harvests (AAH) and 3-year and 5-year average mountain goat harvests, by LEH zone, Management Unit Population Estimate (1994) Population Estimate (25) AAH (3% of 1994 population estimate) 3-Year Average Harvest (22-24) 5-Year Average Harvest (2-24) 3-33A Whitecap B Noel West C McParlon E Noel East F Truax

14 18 16 Total Resident Hunter-Days Total Resident Permits 5-year average - Hunter days 5-year average - Permits Estimated hunter-days Total permits available Figure 4. Estimated hunter-days and LEH permits, Management Unit 3-33, Total Resident Permits Total Resident Harvest 5-year average - Harvest 5-year average - Permits Permits available Total goat harvest Figure 5. Goat LEH permits, harvest and 5-year trends, Management Unit 3-33,

15 .3.25 Goats harvested/ hunter day Figure 6. Mountain goat harvest per unit effort, Management Unit 3-33, Trends in Nanny Harvest The female portion of the harvest in Management Unit 3-32, though highly variable, has averaged 4% over the past decade (Figure 7). In Management Unit 3-33, the recent trend is toward a decreasing proportion of females in the harvest; however, almost 4% of the total harvest in 24 was female, a considerable increase over the previous three years (Figure 8). Population modelling suggests that the long-term viability of hunted mountain goat populations is threatened under female harvests of more than 3% (I. Hatter, pers. comm.). Despite recent efforts province-wide to better educate goat hunters in the sexing of animals in the field (through print and video media available at no charge), nanny harvests are too high, at least in Management Units 3-32 and A system whereby penalties would be applied for the harvest of female goats, i.e. reduction or loss of future hunting opportunities, is being considered. Additional funding for continuing more focussed hunter education programs should be sought. 11

16 Female proportion of total goat harvest year average harvest Figure 7. Mountain goat harvest, by sex, Management Units 3-32, Female proportion of total goat harvest year average harvest Figure 8. Mountain goat harvest, by sex, Management Units 3-33,

17 REFERENCES Ayotte, J st BC Mountain Goat Workshop, March 1 & 2, 25, Prince George: Summary of current issues, management practices and research needs. PWFWCP Report No pp. BC Ministry of Environment, Lands and Parks Wildlife Program Wildlife Harvest Strategy: Improving British Columbia s Wildlife Harvest Regulations. Victoria, BC. 78 pp. Cichowski, D. B., D. Haas and G. Schultze A method used to estimating mountain goat numbers in the Babine Mountain Recreation Area, British Columbia. Proceedings of the Biennial Symposium of the Northern Wild Sheep and Goat Council 6: Gonzalez-Voyer, A., M. Festa-Bianchet and K. G. Smith. 21. Efficiency of aerial surveys of mountain goats. Wildlife Society Bulletin 21, 29(1):14:144. Harper, F. E. 21. A wildlife inventory strategy for ungulate game species within the southern interior region. Unpublished report submitted to Ministry of Environment, Lands and Parks, Kamloops, BC. Morgan, J. 25. A Population Assessment Strategy for Ungulates in the Thompson Region. Unpublished report. Ministry of Water, Land and Air Protection. 13

18 APPENDIX A Survey area and general animal sighting locations: July 25 mountain goat population inventory, Management Units 3-32 and

19