Mountain Goat Abundance and Population Trends in the 

Olympic Mountains, Washington, 2011

Prepared in cooperation with the U.S. National Park Service

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2011-1313
Cover: Photograph of mountain goats in Olympic National Park, Washington, 2011. 

Photograph from National Park Service. 
Mountain Goat Abundance and Population Trends in the 

Olympic Mountains, Washington, 2011

By Kurt Jenkins, U.S. Geological Survey; Patricia Happe, National Park Service; Paul Griffin, U.S. Geological Survey;

and Katherine Beirne, Roger Hoffman, and William Baccus, National Park Service

Open File Report 2011–1313

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Jenkins, K., Happe, P., Griffin, P., Beirne, K., Hoffman, R., and Baccus, B., 2012, Mountain goat 

abundance and population trends in the Olympic Mountains, Washington, 2011: U.S. Geological 

Survey Open-File Report 2011-1313, 22 p.

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iii

Contents

Executive Summary....................................................................................................................................................... 1

Introduction.................................................................................................................................................................... 2

Study Area and Methods ............................................................................................................................................... 3

Sampling.................................................................................................................................................................... 4

Aerial Surveys............................................................................................................................................................ 5

Population Abundance............................................................................................................................................... 6

Population Trends...................................................................................................................................................... 6

Results........................................................................................................................................................................... 7

Aerial Surveys............................................................................................................................................................ 7

Population Abundance............................................................................................................................................... 8

Population Trends...................................................................................................................................................... 8

Discussion ..................................................................................................................................................................... 8

Acknowledgments ........................................................................................................................................................11

References Cited..........................................................................................................................................................11

Appendix 1. Incidental Observations of Other Wildlife Species by Survey Unit, Olympic Mountains, 

Washington, 2011.........................................................................................................................................................17

Appendix 2. Trends in Other Wildlife Species Seen during Goat Surveys in the Olympic Mountains, 

Washington, 1983–2011...............................................................................................................................................18

Appendix 3. Survey Flight Characteristics during Aerial Mountain Goat Surveys, Olympic Mountains, 

Washington, 2011.........................................................................................................................................................19

Appendix 4. Survey Characteristics and Environmental Conditions Measured at the Beginning of Each 

Unit Surveyed in the Olympic Mountains, Washington, 2011 .......................................................................................20

Appendix 5. Raw Counts of Mountain Goats by Survey Unit, Olympic Mountains, Washington, 2011.........................22

Figures

Figure 1. Sampling strata, units surveyed, and number of mountain goats counted during mountain goat 

surveys in the Olympic Mountains, Washington, July 18–25, 2011 ............................................................................. 13

Figure 2. Trends in indices of abundance (solid line) and estimated abundance (dashed line) of mountain 

goats in the Olympic Mountains survey zone, Washington, 1983–2011...................................................................... 14

Tables

Table 1. Mountain goat survey characteristics and raw counts of mountain goats in the Klahhane Special 

Management Concern Area, and high, medium, and low density strata, Olympic Mountains, Washington, 

July 18–25, 2011. ........................................................................................................................................................ 15

Table 2. Population estimates of mountain goats, associated components of variance, standard errors, and 

95-percent confidence intervals in the Olympic Mountains survey zone, Washington, 2004–2011............................ 16
iv

Conversion Factors and Datums

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

SI to Inch/Pound

Multiply By To obtain

Length

meter (m) 3.281 foot (ft)

kilometer (km) 0.6214 mile (mi)

Area

hectare (ha) 2.471 acre 

square kilometer (km2) 0.3861 square mile (mi2) 

Flow rate

kilometer per hour (km/h) 0.6215 mile per hour (mi/h)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32.

Datums

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Elevation, as used in this report, refers to distance above the vertical datum.
1

Mountain Goat Abundance and Population Trends in the

Olympic Mountains, Washington, 2011

By Kurt Jenkins, U.S. Geological Survey; Patricia Happe, National Park Service; Paul Griffin, U.S. Geological 

Survey; and Katherine Beirne, Roger Hoffman, and William Baccus, National Park Service

Executive Summary

We conducted an aerial helicopter survey between July 18 and July 25, 2011, to estimate 

abundance and trends of introduced mountain goats (Oreamnos americanus) in the Olympic Mountains.

The survey was the first since we developed a sightability correction model in 2008, which provided the 

means to estimate the number of mountain goats present in the surveyed areas and not seen during the 

aerial surveys, and to adjust for undercounting biases. Additionally, the count was the first since recent

telemetry studies revealed that the previously defined survey zone, which was delineated at lower 

elevations by the 1,520-meter elevation contour, did not encompass all lands used by mountain goats 

during summer. We redefined the lower elevation boundary of survey units before conducting the 2011 

surveys in an effort to more accurately estimate the entire mountain goat population. We surveyed 39

survey units, comprising 39 percent of the 59,615-hectare survey area. We estimated a mountain goat 

population of 344+44 (standard error, SE) in the expanded survey area. Based on this level of estimation 

uncertainty, the 95-percent confidence interval ranged from 258 to 430 mountain goats at the time of the 

survey.

To permit comparisons of mountain goat populations between the 2004 and 2011 surveys, we 

recomputed population estimates derived from the 2004 survey using the newly developed bias 

correction methods, and we computed the 2004 and 2011 surveys based on comparable survey zone 

definitions (for example, using the boundaries of the 2004 survey). The recomputed estimates of 

mountain goat populations were 217+19 (SE) in 2004 and 303+41(SE) in 2011. The difference between 

the current 2011 population estimate (344+44[SE]) and the recomputed 2011 estimate (303+41[SE]) 

reflects the number of mountain goats counted in the expanded lower elevation portions of the survey 

zone added in 2011. We conclude that the population of mountain goats has increased in the Olympic 

Mountains at an average rate of 4.9+2.2(SE) percent annually since 2004. We caution that the estimated 

rate of population growth may be conservative if severe spring weather deterred some mountain goats 

from reaching the high-elevation survey areas during the 2011 surveys. If the estimated average rate of 

population growth were to remain constant in the future, then the population would double in 

approximately 14–15 years.
2

Introduction

Mountain goats were introduced to the Olympic Mountains during the 1920s prior to the 

establishment of Olympic National Park (Houston and others, 1994). Over the next several decades, the 

population increased in size and expanded throughout the Olympic Range leading to management 

concerns by the mid-1970s over the potential impacts of mountain goats on endemic plants, soils, and 

erosion in subalpine and alpine plant communities (National Park Service, 1995). In 1983, the National 

Park Service (NPS) conducted the first aerial mountain goat survey in the Olympic Mountains, returning 

an estimate of 1,175+171 (SE) mountain goats (Houston and others, 1986). During the mid- to late 

1980s, the NPS conducted an experimental management program to test the effectiveness and determine 

logistical requirements of goat removal and transplanting operations as tools to reduce population size

(Houston and others, 1991a). From 1981 through 1989, 521 goats were removed from the population; 

407 through live capture in the park, 111 through legal hunting outside the park, and 3 known illegal 

kills within the park (Houston and others, 1994). A second survey in July 1990, conducted following 

these removals, produced an estimate of 389+106 (SE) goats (Houston and others, 1991b). Subsequent 

surveys were conducted in 1994, 1997, and 2004 following a period in which no goats were removed by 

NPS managers, returning estimates of 288+32 (SE), 281+22 (SE), and 290+17 (SE) goats, respectively

(National Park Service, unpublished data, 1994, 1997, 2004). Here we report the results from an 

additional (sixth) survey conducted during July 2011 and examine recent population trends. 

Previous estimates of mountain goats inhabiting the Olympic Mountains were based on aerial 

helicopter surveys conducted during mid- to late July in a stratified random sample of survey units that 

collectively encompassed about 50,967 ha of land free of glacial ice above 1,520 m (5,000 ft) elevation

(Houston and others, 1986; Happe and others, 2005; note that area estimates varied slightly among 

previous reports due to refined methods of area estimation over the years). Based on extensive 

observations made in the 1970s and early 1980s (Stevens, 1979, 1983), the lower elevation boundary of 

the survey zone was presumed to include the large majority of summer movements and activity of 

mountain goats (Houston and others, 1986). Raw counts of mountain goats observed by aerial crews

were adjusted upwards by a factor of 1.52 to account for mountain goats not detected during the aerial 

surveys (Houston and others, 1986). This adjustment factor was determined by comparing population 

estimates derived from the 1980s population removal studies to raw index counts of mountain goats 

seen from the helicopter (Houston and others, 1986). The sightability adjustment factor determined in 

this manner accounted for mountain goats that were not detected either because they were outside the 

survey zone boundaries, or because mountain goats that were present within the survey zone were not 

seen by aerial survey crews. The approximate magnitude of the adjustment factor has been substantiated 

by other reports of survey efficiency both locally and regionally (Hoffman, 1987; Johnson, 1983;

Gonzalez-Voyer and others, 2001), but using a constant multiplier has been criticized because it does 

not account for factors that may influence detectability over time, and it underestimates variability of the 

resulting population estimates (Noss and others, 2000). 

Between 2005 and 2008, we placed global-positioning system (GPS) radio-collars on 11 

mountain goats in Olympic National Park as part of a comprehensive study of detection bias in 

helicopter-based surveys of mountain goats in western Washington (Rice and others, 2009; Jenkins and 

others, 2011). Based on repeated aerial surveys over GPS-collared mountain goats, we developed a 

sightability model that estimates the probability of detecting any group of mountain goats during an 

aerial survey as a function of the number of mountain goats present in the group as well as vegetation 

cover and the presence of terrain obstruction in the immediate area around each group (Rice and others,

2009). This model may be used to adjust the raw counts of mountain goats seen during the survey based 

on the estimated detection probability of each individual group detected. For example, if the detection 
3

probability of a single observed group of mountain goats was estimated to be 0.75, then the number of 

mountain goats within that group would be multiplied by a correction factor of 1.33 (that is, 1 divided 

by 0.75) to account for goats that were not seen under comparable environmental conditions.

Sightability models have been developed for several ungulate species throughout North America and are 

widely used to adjust raw counts of animals seen during aerial surveys to more accurately represent 

actual numbers present (Samuel and others, 1987; Ackerman, 1988; Bodie and others, 1995; Anderson 

and Lindsey, 1996).

We also documented the summer movements of GPS-collared mountain goats to determine 

whether the previously defined aerial survey boundaries adequately encompassed the population during 

summer (Jenkins and others, 2011). Analyses of movements of GPS collared mountain goats revealed 

that movements of mountain goats to lower elevations outside the prescribed survey zone may have 

resulted in previous surveys undersampling the population by as much as 30 percent. That potential bias 

was likely corrected by the 1.52 bias correction term used in previous surveys, but the recently 

developed models of detection bias do not account for mountain goats outside the surveyed areas. Our 

studies indicated that surveying to lower elevations in areas around rocky escape terrain would include a

greater proportion of the mountain goat population and, coupled with the sightablility model, would 

produce more accurate population estimates without increasing the survey costs and coverage 

appreciably (Jenkins and others, 2011).

Hence, we made two important changes to the aerial survey protocol in 2011 to more accurately 

estimate the mountain goat population. First, we adjusted the survey boundaries to include a greater

proportion of the summer range used by mountain goats. Second, we adjusted aerial survey counts to 

account for detection biases using the sightability model (Rice and others, 2009). Here we report the 

estimated number of mountain goats inhabiting the Olympic Mountains and determine population trends 

between 2004 and 2011. 

Study Area and Methods

The Olympic Mountains are noted for steep gradients in elevation, vegetation, and precipitation

within a context of highly convoluted topography and landforms (Tabor, 1987; Henderson and others,

1989). The Olympic Mountains rise abruptly from the coastal plains and foothills, culminating in Mount 

Olympus, the highest peak at 2,430 m elevation, and 37 other major peaks exceeding 2,130 m elevation,

all within about 50 km of the sea (Houston and others, 1994). Eleven major watersheds drain radially

from the Olympic Mountains to the Pacific Ocean to the west, Strait of Juan de Fuca to the north, and 

Hood Canal to the east. Moist Pacific storms, generally arriving from the southwest and intercepted by 

the Olympic Range, result in steep gradients in precipitation. Precipitation increases with elevation

along the southern and western slopes of the Olympic Mountains, reaches a peak in the interior 

mountains, and decreases sharply in the leeward northeastern Olympics. Winter precipitation falls 

primarily as rain in lowlands below about 300–500 m, as rain and snow at intermediate elevations, and 

primarily as snow above 1,000 m elevation.

As in all previous surveys of mountain goats in the Olympic Mountains, we surveyed during 

mid- to late July to target the seasonal window after mountain goats have moved to higher elevations for 

summer (Rice, 2008; Jenkins and others, 2011) but before hot mid-summer temperatures present 

operational difficulties for flying at high elevations. Abnormally heavy snowfall, unseasonably cool 

spring weather, and late snowpack persisted during the 2011 survey. The snowpack was about 160

percent of normal on April 1 and 200 percent of normal on May 1 based on a 60-year record for two

high-elevation snow surveys conducted annually in the Olympic Mountains (National Park Service, 

unpublished data, 2011). The SNOTEL monitoring station at Hurricane Ridge in the northern Olympic 
4

Mountains (1,524 m) generally becomes snow free between July 10 and July 15 (based on a 10-year 

record), but snow persisted until July 24, 2011 (National Park Service, unpublished data, 2011).

Although steep terrain was largely free of snow during the surveys, particularly on southern aspects and 

in the drier northeast, shaded areas such as north- and east-facing cirques, bowls, and forested areas 

were still snow covered throughout much of the survey area. 

Sampling

We made two adjustments to the sampling frame for the 2011 survey. First, we omitted the 

Mount Washington sampling unit (Olympic National Forest, southeastern Olympic Peninsula) from the 

survey due to logistical difficulties and funding limitations. Second, we added lower elevations in areas 

of suitable habitat to the previously defined survey units that were used from 1983 through 2007. 

Additional suitable habitat was identified as land between 1,425 and 1,520 m elevations where escape 

terrain comprised at least 50 percent of the elevation band. We defined escape terrain as area less than 

111 m from any 25×25-m (0.0625 ha) raster cell classified as rock (Olympic National Park vegetation 

cover map, Pacific Meridian Resources, 1996) and with slope greater than 33 percent. We chose the 

111-m threshold because 90 percent of all locations of GPS-collared mountain goats were less than 111

m from escape cover when they were lower than 1,520 m in elevation during the July sampling window.

The 50-percent classification was a subjective decision that reflected costs and logistical considerations 

to minimize survey effort over relatively large areas of low-quality and unused habitats. 

As in past surveys, we used stratified random sampling procedures to select sampling units for 

aerial surveys. Due to the addition of lower elevations to the previously defined survey units, we 

occasionally redefined unit boundaries in an effort to maintain consistency in survey unit sizes at about 

500 ha. If a unit was split, the new name retained the original number (for example, 127 was split into 

127N and 127S) for ease of comparisons across survey years. If a wholly new survey area was added to 

accommodate the new acreage additions, we assigned a new survey unit number. The expanded survey 

zone comprised a total of 108 sampling units covering 59,615 ha. The addition of lower elevation 

habitats in 2011 increased the survey zone by 18 percent over the area included in the sampling frame 

used for previous surveys, which was 50,567 ha excluding the Mount Washington Unit. 

As in years past, we assigned each of the survey units to one of four survey strata prior to the 

surveys. These included areas of special management concern, low-density, medium-density, and highdensity strata. Stratum assignments for each survey unit were based on the results of past mountain goat 

surveys and recent observations reported by park staff.

a) Areas of special management concern: The only unit in this category in 2011 was the area 

designated in previous surveys as the Klahhane Ridge Total Count Unit. We maintained 

Klahhane Ridge in this category for continuity with previous surveys, and because it was the site 

of intensive population manipulation and study during the 1970–90s and it remains an area of 

management concern today. The Klahhane Ridge unit comprised 2,041 ha.

b) Known or suspected high-density areas: Units were assigned to this stratum if we expected to 

find 10 or more mountain goats per 500 ha based on previous surveys and field observations. 

Between 2004 and 2011, numbers of goats reported by visitors and park staff increased. Based 

on that information, we increased the number of suspected high-density areas from four survey 

units comprising 3,547 ha in 2004 to 10 units covering 7,606 ha in 2011. We surveyed all units 

in the high density stratum.
5

c) Known or suspected medium-density areas: Units were assigned to this stratum if we expected 

1–9 mountain goats per 500 ha inhabiting the survey unit. The medium-density stratum 

comprised 20,599 ha in 41 survey units ranging in size from 220 to 712 ha. We randomly 

selected 22 survey units (54 percent) in the sample. 

d) Known or suspected low-density areas: Units were assigned to this stratum if we expected no 

mountain goats. The low-density stratum comprised 29,369 ha in 56 survey units ranging in size 

from 363 to 659 ha. Six survey units (11 percent) were randomly selected in the sample.

After allotting survey time for all high-density units and Klahhane Ridge, we allocated the 

remaining survey effort among low- and medium-density strata using standard optimal allocation 

methods (Cochrane, 1977) based on sampling variances reported in 2004 (Happe and others, 2005).

Aerial Surveys

Aerial survey procedures were similar to those used in previous surveys (Houston and others,

1986, 1991b; Happe and others, 2005; Rice and others, 2009). Most surveys were conducted between

dawn and about 10:30 a.m. by a pilot and three-person crew aboard an MD-500D helicopter. The pilot’s 

primary responsibility was to safely fly the aircraft but the pilot also reported observations. We counted 

mountain goats within the selected survey units by flying multiple contours about 100 m from the 

terrain (that is, above flat terrain or horizontally away from vertical terrain) at elevations spaced 90–150

m apart vertically. Flight speed was maintained between 56 and 72 km/h (35–45 mi/h). Lower 

elevations of each unit were flown first and then the helicopter progressively worked upslope until the 

entire unit was searched. We used a GPS unit aboard the helicopter during all surveys to assist with 

navigation, map flight paths, and record the approximate locations of goat groups and other wildlife 

seen during the surveys.

We recorded conditions related to each helicopter flight, survey unit, and group of mountain 

goats observed. For each flight, we recorded crew members’ names and various flight descriptors (times 

and locations of takeoffs and landings). We recorded times at the start and end of each unit surveyed

and several environmental conditions, including cloud cover, wind strength, precipitation level, and 

temperature. Upon spotting a group of mountain goats, observers recorded the total number of mountain 

goats, number of young of the year (kids), and the following covariates: activity of most animals when 

first sighted (bedded, standing, or moving), substrate for most animals when first sighted (rock, snow, 

herbaceous vegetation, or forest), the percentage of vegetation obstruction cover capable of obscuring a 

mountain goat within a 10-m buffer around the group (0, 1–25, 26–50, 51–75, 76–100), and whether 

terrain obstruction was present within a 10-m buffer around the group at the moment it was first seen. 

We defined terrain obstruction as any landform capable of obscuring a mountain goat from the air. The 

group size, vegetation, and terrain obstruction covariates were used to estimate group specific detection 

probabilities for bias correction (Rice and others, 2009). 

We also recorded whether each observed group was in the newly added area at lower elevations 

within each survey unit (that is, between 1,425 and 1,520 m elevations) and whether the group was

below, level with, or above the helicopter flight line. These last two pieces of information were recorded 

to compare mountain goat abundance in 2011 to previous estimates made within the more restricted 

survey area. Lastly, we recorded sightings of other wildlife observed incidental to the survey. These 

incidental observations are summarized in appendixes 1 and 2 and are not discussed further here. 
6

Population Abundance

We estimated mountain goat abundance using the sightability modeling approach developed by 

Steinhorst and Samuel (1989). This approach combines counts of animals, or groups of animals, in a set 

of randomly sampled survey units with a model for their probability of detection. For a stratified 

random sample of survey units, the estimate of population size (τ̂) is given by:

τ̂= ∑ ∑ ∑ �

Nh

nh

θ�

h,i,jYh,i,j� (1)

where the sums are over strata (h), sampled survey units (i), and observed groups (j); nh and Nh are, 

respectively, the number of stratum h plots in the sample and in the population; the θ�’s are estimated 

sightability correction factors associated with each observed group (~ the inverse of each group’s 

detection probability); and Yh,i,j gives the number of animals in the j

th observed group (within the ith

survey unit in stratum h).

We estimated sightability correction factors for each observed group using model-averaged 

regression coefficients and their unconditional variance covariance matrix from Rice and others (2009) 

along with formulas from Steinhorst and Samuel (1989). Specifically, Rice and others (2009) used 

sighting data from 205 sightability trials to model the probability of detection for each mountain goat 

group (j), pdetect,j , as a function of group size (Group Sizej), percent vegetative obstruction (% Vegj), 

and terrain obstruction (Terrainj).

pdetect,j = e(β1+β2∗GroupSize,j+β3∗Terrain,j+β4∗%Veg,j)

1+e(β1+β2∗GroupSize,j+β3∗Terrain,j+β4∗%Veg,j) = 

e(xj

′β )

1+e(xj

′β ) (2)

The estimated regression coefficients (β̂; Rice and others, 2009, p. 474) and their estimated 

unconditional variance/covariance matrix, Σ� (Rice and others, 2009, p. 474), were then used to estimate 

the sightability correction factors using the following equation from Steinhorst and Samuel (1989):

θ�

h,i,j = 1 + e(−xj

′β� − xjΣ�xj

′

2 ) (3)

Three random processes create uncertainty in the estimated abundance (τ̂): (1) the random 

sampling of survey plots; (2) random detection (and failed detection) of independent groups within 

surveyed plots; and (3) variation in estimation of parameters used to model sightability. Wong (1996) 

developed consistent (asymptotically unbiased) estimators of each of these variance components. We 

used a script (Sightability.Model) for Program R (R Development Core Team, 2011) developed by John 

Fieberg (Minnesota Department of Natural Resources, Forest Lake, Minnesota), to estimate total 

abundance using the Steinhorst and Samuel (1989) estimator (eq.1), and Var(τ̂) using equations from

Wong (1996).

Population Trends

It was not possible to determine population trends directly from surveys conducted from 1983 to 

2011 because of changes made to the sampling area in 2011 as well as changes to methods used to 

estimate detection biases. However, because we collected covariate data associated with mountain goat 

observations in 2004, we adjusted the 2004 data for detection biases using the sightability model and 

compared population estimates and determined the rate of population growth between 2004 and 2011.
7

To place the 2004 and 2011 population estimates in historical context, we computed population 

indices from all counts conducted from 1983 to 2011. Population indices were the estimated counts of 

mountain goats throughout the Olympic Mountains prior to any adjustments to account for detection 

biases. These population indices were computed using stratified random sampling computational 

methods described by Norton-Griffiths (1978) and used by Houston and others (1986, 1991b).

Consequently, these indices are minimum population estimates because they do not account for animals 

present but not seen during surveys. Moreover, the comparison of population indices over time assumes 

that sightability of mountain goats did not change over time.

To compare the 2004 and 2011 population estimates and the 1983 to 2011 index values, it was 

necessary to ensure that comparisons were based on the same surveyed areas. We made the following 

adjustments to account for differences in survey boundaries among years: (1) all observations of 

mountain goats from the new survey areas added in 2011 were removed from the 2011 dataset (that is,

observations between 1,425 and 1,520 m elevations), (2) observations from the Mount Washington 

Unit, which was not surveyed in 2011, were removed from the 1983–2004 datasets. Hence, abundance

estimates and indices reflect numbers of mountain goats in lands free of permanent snow and ice above 

1,520 m elevation and excluding the Mount Washington Unit in the Olympic National Forest (fig. 1). 

We used a 2-tailed z-test to determine whether or not two estimates of abundance differed 

statistically from a null hypothesis of zero change (Thompson and others, 1998). We also estimated both 

the instantaneous rate of exponential population growth and the average finite rate of growth necessary 

to cause the observed changes in estimated abundance from 2004 to 2011, based on the difference of the 

log-transformed abundance estimates (Caughley, 1977, p. 51). Because we used the same sightability 

model to estimate abundance of mountain goats in 2004 and 2011, we used the Sightability. Model 

script in program R, which takes into account the covariance between years, and to estimate variance of 

the population growth rate (R Development Core Team, 2011; available from J. Fieberg, Minnesota 

Department of Natural Resources, Forest Lake, Minnesota). 

Results

Aerial Surveys

We conducted aerial surveys during six mornings from July 18 to July 25, 2011. We surveyed 

mountain goats within 39 survey units totaling 23,458 ha (table 1). This is similar to the amount of area 

surveyed in 2004 (that is, 41 survey units comprising 24,524 ha in 2004; Happe and others, 2005). 

Although the total area surveyed was comparable in 2004 and 2011, because we expanded the total 

survey zone to include lower elevations in 2011, we sampled a lower proportion of the total survey zone

in 2011 (39 percent) than in 2004 (48 percent). Total flight time, including travel between survey units 

and fueling locations, was 27.1 hours in 2011. Of that, we actively searched for mountain goats within 

survey units for 18.4 hours (1,106 min, table 1). This is slightly less efficient than in 2004, when flight 

time was 25.8 hours including 18 hours on survey. 

Survey intensity averaged 4.7 min/km2 across all surveyed units, ranging from 3.7 to 5.3 

min/km2 in the low and high-density strata, respectively (table 1). Differences in survey intensity among 

survey units and strata reflected variation in habitat complexity and the time required to count mountain 

goats and record observations, rather than any variation in our expectation of finding goats. Detailed 

summaries of all individual flights and survey conditions are provided in appendixes 3 and 4, 

respectively. 
8

Population Abundance

We counted a total of 217 mountain goats in the four strata (table 1, fig. 1). The estimated 

population of mountain goats within the Olympic Mountains survey zone (all estimates exclude Mount

Washington) corrected for detection bias was 344+44(SE) at the time of the survey (table 2). The total 

variance of the population estimate, Var(τ̂), was 1,924, which accounts for variance associated with 

random sampling of survey units (Varsampling=1,212 or 63 percent of the total), random detections of 

independent groups (Vardetection=432 or 22 percent of total), and uncertainty in model estimation

(Varmodel=280 or 15 percent of total). The 95-percent confidence interval, defined as the 

estimate+1.96(SE), ranged from 258 to 430 mountain goats.

Population Trends

Population estimates corrected for detection biases and adjusted for comparable survey areas 

were 217+19(SE) mountain goats in 2004 and 303+41(SE) mountain goats in 2011 (table 2, fig. 2). 

Compared with the abundance estimate of 344 mountain goats for the expanded survey zone used in 

2011, the estimate of 303 mountain goats presented here pertains to the more restricted survey zone

defined in previous years (that is, areas above 1,520 m elevation). The estimated population in the 

expanded survey zone was approximately 14 percent greater than in the original survey area, reflecting 

mountain goats observed in the newly added area between 1,425 and 1,520 m elevations during the 

2011 surveys. 

Based on population estimates of mountain goats within the comparable survey zone, mountain 

goat abundance was greater in 2011 than in 2004 (z=2.04, P=0.04). The z-statistic indicated that a 

difference in population estimates of this magnitude (or greater) would only occur 4 percent of the time 

if the null hypothesis of equal population size was true. The estimated population of mountain goats 

increased at an instantaneous rate (r) of 0.048+0.021(SE) between 2004 and 2011, representing a 4.9 

percent finite rate of population increase annually (that is, λ=1.049+0.022 [SE]).

Minimum population indices of mountain goats in the Olympic Mountains survey zone, 

excluding Mount Washington area, ranged from a high of 755+116(SE) in 1983, to lows of 171+15(SE)

in 1997 and 179+10(SE) in 2004 following the experimental removals. The population index increased 

to 232+27(SE) in 2011 (fig. 2). 

Discussion

After a relatively long period of population stability following the experimental population 

reductions in the 1980s, the mountain goat population increased in the Olympic Mountains survey zone 

between 2004 and 2011. The reasons for the long period of population stability and the relatively slow 

rate of population growth from 1994 to 2004 are poorly understood. Mountain goats are sensitive to 

high rates of removal, such as those implemented during the experimental reductions in the 1980s, due 

to their relatively low rate of reproduction and the combined additive effects of natural and humancaused mortality or other removals (Côté and Festa-Bianchet, 2003; Hamel and others, 2006). 

Population recovery from over harvest or culling appears to be highly individualized among different 

populations, but is hindered most in small populations that may be more susceptible to stochastic events 

such as density-independent mortality (Hamel and others, 2006; Rice and Gay, 2010). Recent genetic 

studies, which revealed low allelic diversity and evidence of inbreeding in the Olympic Mountains,

suggest that genetic factors also played a role in the slow return of mountain goats to the Olympics, as 

throughout parts of the Cascades (Shirk, 2009). The interaction between population performance and 

genetics of mountain goats in Washington remains speculative, but survival rates of sub-adult mountain 
9

goats has been shown to be affected negatively by low genetic diversity in Alberta (Mainguy and others,

2009). Reasons for the recent upturn in the number of mountain goats in the Olympics also remain 

poorly understood.

Despite efforts to survey a more complete segment of the total population and adjust for 

detection biases in 2011, the resulting population estimate still must be considered a minimum estimate. 

We estimated about 14 percent more mountain goats by expanding the survey zone by 18 percent to 

include escape terrain at comparatively low elevations in 2011. Because GPS-collared mountain goats 

have been observed using elevations less than 1,400 m elevation (Jenkins and others, 2011), the 

expanded survey boundaries are unlikely to include the entire population. We have no means to estimate 

the effects of the unseasonably late and deep snows on mountain goat distribution patterns and 

detectability in 2011, but we suspect the near-record late and persistent snows may have reduced 

mountain goat use of some survey units. We received one report of mountain goats seen by NPS staff at 

low elevations outside the survey zone during our surveys. Furthermore, we counted no mountain goats 

in one survey unit where mountain goats have been common in recent years, and where mountain goats 

appeared after surveys were completed. Our previous studies did not reveal an effect of snow on aerial 

detectability of mountain goats (Rice and others, 2009), but snow depths and cover were greater during 

2011 than during the years of model development. The effects of extensive snow cover on goat 

sightability and distribution is not known. Hence, we caution that our population estimate is 

conservative, reflecting only the number of goats present in areas of acceptable escape terrain greater 

than 1,425 m elevation at the time of the 2011 survey. If the combination of weather and goat behavior 

led us to underestimate the actual population size in 2011, it also would lead to underestimating the

actual population differences and the rate of population growth estimated between 2004 and 2011. 

Modifications made to survey design and methodology in 2011 increased the accuracy of 

mountain goat population estimates. We estimated 44 percent more goats in 2011 by adjusting survey 

boundaries to lower elevations in areas of suitable habitat and by correcting for sightability biases. We 

derived this percentage based on comparing the bias-corrected population estimate in 2011 

(344+44[SE]) to the unadjusted index count of mountain goats within the survey boundaries used in 

previous surveys (that is, above 1,520 m elevation; 239+26[SE]). These numbers return a correction 

ratio of 1.44, which is similar to the ratio of 1.52 used in earlier surveys (Houston and others, 1986, 

1991b). If deep snows caused us to underestimate the population of mountain goats in 2011, then we 

may have underestimated the true detection bias in 2011 and average correction factors derived from the 

past and present methods may be even more similar than indicated. The similarity of detection biases 

estimated here to those applied in past surveys supports the contention that the historically adjusted 

numbers were more representative of actual populations than were indices based on raw counts alone 

(Houston and others, 1986, 1991b).

Using the sightability model rather than a constant ratio estimator of detection bias allowed us to 

capture more sources of uncertainty in 2011 than in past years. Variances, standard errors, and 

confidence intervals—all measures of uncertainty in the population estimates—were greater during 

2011 than in 2004 (table 2, fig. 2). Estimated precision reflected annual differences in sampling 

variation and estimation methods, which in 2011 included methods to estimate variance associated with 

random detection and model estimation, not just sampling variability (Steinhorst and Samuel, 1989;

Wong, 1996). Sampling variability contributed 63 percent of the total variance in 2011 population 

estimates but only 37 percent of total variance in 2004. These trends indicate that sampling variability

was higher in 2011 than 2004, but also that previous surveys underestimated the total variance by not 

accounting for uncertainties associated with random detection and sightability modeling.
10

Greater sampling variation in 2011 was related to several factors. First, high counts of goats

were unexpected in three counting units in the moderate-density stratum in 2011 (11–15 goats, fig. 1), 

which increased sampling variation. Second, because we expanded the survey area in 2011 and 

increased sampling efforts in the high-density stratum, we surveyed a smaller proportion of the total 

survey area in 2011 (39 percent) than in 2004 (48 percent), and an even lower relative proportion of the 

variable moderate-density stratum (52 versus 84 percent, respectively). We were not able to achieve the 

same sampling intensity in 2011 as in 2004 because we operated on a fixed budget while surveying a 

larger area in 2011.

Measures to increase survey accuracy and precision would improve the ability of managers to 

detect population trends and manage mountain goat populations most effectively in the future. Although 

we have invested heavily to obtain a more accurate method of population estimation, the influence of 

unseasonable weather on mountain goat distribution remains a potential source of inaccuracy. In years 

of uncharacteristic late season and deep summer snow, postponing surveys until September or another 

year may help to ensure that all mountain goats are present at high elevations during the survey and the 

entire population is estimated accurately. 

Changes in logistics and survey design also may increase precision of future surveys. Precision 

of population estimates is determined by overall survey effort as well as variability of counts within 

sampling strata. Survey effort, defined as the total area surveyed, is controlled most directly through 

funding level, but also could be increased by improving survey efficiency (that is, surveying more area

on the same budget). Survey flight speeds are defined by the sightability model protocol and have been 

constant since the early 1980s, so increasing flight speed or adjusting survey coverage are not viable 

options for increasing survey efficiency. Efficiency may be increased, however, by fueling out of more 

centrally located staging areas than used in 2011. In 2011, we fueled out of Deer Park in the 

northeastern Olympics due to deep snows that prevented fueling at Obstruction Point, a more centrally 

located fueling and staging area. A return to using Obstruction Point should reduce travel times 

associated with refueling and increase overall survey efficiency during years of less snow. 

The history of mountain goat surveys in the Olympic Mountains demonstrates the inherent 

variability of these surveys, and the difficulty of reducing sampling variability. Unexpected high counts 

of goats outside the predicted stratum bounds have been a recurring issue (Houston and others, 1986, 

1991b), likely due to the clumped distribution and wide movements of goats relative to sampling units. 

It seems unlikely that we will be more successful in the future in reducing within-strata sampling 

variability, particularly in a period of increasing populations. Hence, with more area to survey and the 

population increasing, more funding than was used in 2011 would be needed to achieve greater 

precision in future surveys. Because sampling variability is determined by unit-to-unit variability in 

estimated numbers of goats, it may be beneficial to stratify based on expected numbers of goats within 

survey units rather than density. Additionally, increasing the relative sampling allocation to the variable 

moderate-density stratum may reduce sampling variation and enhance the precision of future surveys.

Although current evidence points to an increasing population of mountain goats in the Olympics, 

uncertain effects of climate and genetic factors obscure future trends. If the estimated average rate of 

population growth were to remain constant, however, the population would increase by 50 percent in the 

next 8–9 years and would double in 14–15 years. Now that the population has begun to increase

following control measures of the 1980s and a period of relative stability in the 1990s, more frequent 

surveys may be warranted to better inform mountain goat planning and management activities in the 

future.
11

Acknowledgments

This study was funded principally by the National Park Service Natural Resources Preservation 

Program Regional Block Grant through an interagency agreement to the USGS Forest and Rangeland 

Ecosystem Science Center. Additional funding was provided by Olympic National Park. We would like 

to thank Larry Nickey, Todd Rankin, Corky McKeown, Stephanie Frey, and the staffs at the Emergency 

Operations Center and Dispatch Office at Olympic National Park for their help in aviation planning and 

communications during the surveys. We are grateful to Trever Walker (Northwest Helicopters) for 

safely piloting all surveys. John Fieberg, Minnesota Department of Natural Resources, graciously 

shared software applications and consulted with us on computational methods. John Fieberg, Doug 

Houston, and Cliff Rice provided very helpful reviews of this manuscript. We are grateful for the 

assistance of Ruth Jacobs, Shirley Koetz, and Linda Rogers in preparing this publication.

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12

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13

Figures

Figure 1. Sampling strata, units surveyed, and number of mountain goats counted during mountain goat surveys in the Olympic Mountains, 

Washington, July 18–25, 2011. Raw total counts and number of kids (young of the year) are presented in appendix 5.
14

Figure 2. Trends in indices of abundance (solid line) and estimated abundance (dashed line) of mountain 

goats in the Olympic Mountains survey zone, Washington, 1983–2011. The solid black line connects point 

estimates of the minimum population indices (+SE), excluding the Mount Washington survey unit. The 

dashed line connects the 2004 and 2011 sightability-adjusted estimated abundance of mountain goats, 

excluding the Mount Washington survey unit. Standard errors of the minimum population indices account 

for sampling variability only, whereas standard errors of the population estimates account for sampling 

variation, random detection, and sightability model estimation.
15

Tables

Table 1. Mountain goat survey characteristics and raw counts of mountain goats in the Klahhane Special Management Concern Area, and high, 

medium, and low density strata, Olympic Mountains, Washington, July 18–25, 2011.

[ha, hectares; min, minutes; min/km2, minutes per square kilometer]

Stratum Area (ha)

Number 

of units

Area 

sampled (ha)

Units

sampled

Percentage of

stratum

surveyed

Survey

time (min)

Survey 

intensity

(min/km2)

Number of 

goats

Klahhane SMC 2,041 1 2,041 1 100 74.5 3.7 11

High 7,606 10 7,606 10 100 406.0 5.3 155

Medium 20,599 41 10,811 22 52 514.4 4.8 50

Low 29,369 56 3,001 6 10 111.4 3.7 1

Total 59,615 108 23,458 39 39 1,106.3 4.7 217
16

Table 2. Population estimates of mountain goats, associated components of variance, standard errors, and 95-percent confidence intervals in the 

Olympic Mountains survey zone, Washington, 2004–2011.

[For comparison among years, estimates in 2011 are computed for two survey unit definitions: the expanded survey unit boundaries, which included suitable 

habitats above 1,425 m elevation, and the original survey unit boundaries including lands above 1,520 m elevation. For comparability, both survey definitions 

exclude the Mount Washington Survey Unit in the southeastern Olympic Mountains, which was not surveyed in 2011]

Survey unit Estimate Variance component1

Year definition (Number 

of goats) Total Sampling Detection Modeling Standard error2

95percent 

confidence 

interval3

2011 Expanded 344 1,924 1,212 432 280 44 258–430

2011 Original 303 1,668 1,048 388 232 41 223–383

2004 Original 217 375 137 160 78 19 180–254

1 Variance components as defined by Steinhorst and Samuel (1989) were computed following Wong (1996).

2 Computed as square root of total variance.

3 Computed as estimate +1.96(SE).
17

Appendix 1. Incidental Observations of Other Wildlife Species by Survey 

Unit, Olympic Mountains, Washington, 2011. 

[The number of individuals observed in the lower elevation survey zone newly designated in 2011 is listed in 

parentheses. Stratum: SMC, Special Management Concern; H, high density; M, medium density; L, low density]

Stratum Unit Bear Deer Elk

Golden 

Eagle Marmot

Band-tailed 

Pigeon

SMC 1 3 (1) 5 1 2

H 69 1 (1) 4 3 (3)

H 93

H 115

H 125 4 (3) 2 1 (1)

H 127N

H 127S

H 129 1

H 131 1 (1)

H 137 4 (3) 3 (3)

H 141 1 (1) 24 (24)

M 48 2 (1)

M 54

M 55 5

M 65

M 72 3

M 73E 1 10 (10)

M 73W 2

M 76 2

M 81E

M 83 1 (1)

M 91 2

M 94

M 95

M 97 1

M 116E

M 117 4

M 122

M 123

M 124

M 130

M 132 8

M 135 3 (2)

L 22 2 2 1

L 41

L 50

L 64

L 87

L 140 1 (1) 1

Totals 35 (15) 25 (3) 46 (38) 2 2 1
18

Appendix 2. Trends in Other Wildlife Species Seen during Goat Surveys in the Olympic Mountains, 

Washington, 1983–2011. 

Observations are scaled to a 500-ha basis to adjust for variable amount of area surveyed over the years. Counts have not been adjusted 

to account for detection bias or to account for changes in survey unit boundaries among years. 
19

Appendix 3. Survey Flight Characteristics during Aerial Mountain Goat Surveys, Olympic Mountains, 

Washington, 2011. 

[All surveys were conducted using a MD-500D aircraft piloted by Trever Walker, Northwest Helicopters. The total flight time, not including transit times from 

and to Olympia, was 1,629 minutes, including 1,106 minutes on survey. min, minutes; Mtn, mountain]

Departure 

time

(a.m.)

Departure 

location

Arrival

Time

(a.m.)

Arrival location Flight 

duration 

(min)

Survey 

duration1

(min)

Observer/Seating position

Flight 

No. Date Left back2 Right front3 Right back4

1 7/18/11 5:40 Port Angeles 7:15 Blue Mtn 95.0 59.0 Beirne Happe Baccus

2 7/18/11 7:34 Blue Mtn 9:08 Blue Mtn 94.0 64.2 Beirne Happe Griffin

3 7/18/11 9:36 Blue Mtn 10:51 Port Angeles 75.0 39.3 Beirne Happe Griffin

4 7/19/11 5:40 Port Angeles 7:12 Blue Mtn 92.0 47.6 Beirne Happe Baccus

5 7/19/11 7:35 Blue Mtn 9:16 Blue Mtn 101.0 74.6 Beirne Happe Baccus

6 7/19/11 9:35 Blue Mtn 10:36 Port Angeles 61.0 30.0 Beirne Happe Baccus

7 7/22/11 5:27 Port Angeles 7:10 Blue Mtn 103.0 62.1 Beirne Happe Baccus

8 7/22/11 7:26 Blue Mtn 9:09 Blue Mtn 103.0 69.9 Beirne Happe Baccus

9 7/22/11 9:25 Blue Mtn 10:50 Port Angeles 85.0 53.0 Beirne Happe Griffin

10 7/23/11 5:30 Port Angeles 7:05 Blue Mtn 95.0 64.5 Beirne Happe Baccus

11 7/23/11 7:24 Blue Mtn 9:02 Blue Mtn 98.0 52.1 Beirne Baccus Happe

12 7/23/11 9:18 Blue Mtn 11:01 Port Angeles 103.0 61.4 Beirne Happe Griffin

13 7/24/11 5:30 Port Angeles 7:05 Blue Mtn 95.0 62.0 Beirne Jenkins Baccus

14 7/24/11 7:28 Blue Mtn 8:06 Blue Mtn 38.0 74.6 Beirne Jenkins Baccus

15 7/24/11 9:26 Blue Mtn 10:38 Blue Mtn 72.0 45.6 Beirne Jenkins Baccus

16 7/25/11 5:40 Blue Mtn 7:21 Blue Mtn 101.0 75.5 Beirne Jenkins Griffin

17 7/25/11 7:39 Blue Mtn 9:09 Blue Mtn 90.0 65.1 Beirne Jenkins Griffin

18 7/25/11 9:26 Blue Mtn 10:56 Blue Mtn 90.0 74.5 Beirne Happe Griffin

19 7/25/11 11:08 Blue Mtn 11:46 Blue Mtn 38.0 19.6 Beirne Happe Griffin 1

Total time spent on surveys excluding time spent flying to and among survey units.

2

Navigator: operated GPS during surveys. 

3

Primary observer: focused on searching for goats at all times.

4

Data recorder: recorded all observations and covariate data.
20

Appendix 4. Survey Characteristics and Environmental Conditions Measured at the Beginning of Each 

Unit Surveyed in the Olympic Mountains, Washington, 2011.

[Polygons are subunits that are used for data recording and survey planning. Duration of survey within each surveyed unit. Ppt: Precipitation level. Elevation at 

which air temperature was recorded. Illumination refers to lighting conditions during the survey. High contrast lighting casts shadows whereas flat lighting does

not. o

C, degrees Celsius; ft, feet; min, minutes; km2, square kilometer]

Flight 

No. Date Unit ID

Polygon 

ID(s)

Unit 

area 

(km2)

Survey 

duration

(min)

Survey 

intensity

(min/

km2)

Sky

condition Winds Ppt

Cloud 

cover

(percent)

Temp 

(oC)

Elevation

(ft) Illumination

1 7/18/2011 115 114,115 6.08 33.2 5.5 clear calm none 0 5 6,500 high

1 7/18/2011 116E 116E 5.53 25.8 4.7 clear calm none 0 12 5,800 high

2 7/18/2011 122 122 3.99 29.6 7.4 clear calm none 0 8 5,800 high

2 7/18/2011 123 123 6.98 34.6 5.0 clear calm none 0 3 7,000 high

3 7/18/2011 124 124 6.98 39.3 5.6 mostly clear calm none 10 8 6,000 high

4 7/19/2011 91 91,92 4.31 16.9 3.9 mostly clear none 20 high

4 7/19/2011 93 93 5.78 30.7 5.3 mostly clear light none 20 10 5,500 high

5 7/19/2011 137 137,139 12.44 67.4 5.4 mostly cloudy calm none 80 5 6,000 flat

5 7/19/2011 135 136 1.97 7.2 3.7 mostly cloudy calm none 80 9 flat

6 7/19/2011 140 140 6.01 23.4 3.9 mostly clear light 80 6 4,000 high

6 7/19/2011 135 135 1.53 6.6 4.3 mostly clear light none 40 6 5,300 high

7 7/22/2011 127S 127S 3.45 17.5 5.1 clear light none <10 8 5,000

7 7/22/2011 125 125,126 5.51 44.6 8.1 clear light none 15 5 7,000 high

8 7/22/2011 125 128 9.12 55.1 6.0 mostly clear light none 40 7 6,300 flat

8 7/22/2011 127N 127N 2.40 14.8 6.2 mostly clear light none 30 8 5,800 high

9 7/22/2011 129 129 6.67 23.5 3.5 mostly clear moderate none 10 7 4,500 high

9 7/22/2011 130 130 5.84 29.5 5.1 mostly clear light none 5 8 6,300 high

10 7/23/2011 69 103,78,69 14.19 64.5 4.5 clear light none 0 8 4,000 high

11 7/23/2011 97 97 2.74 15.4 5.6 clear calm none 0 11 5,000 high

11 7/23/2011 94 94 6.19 27.6 4.5 clear calm none 0 11 high

11 7/23/2011 95 95 2.20 9.2 4.2 clear calm none 0 11 high

11 7/23/2011 87 89 2.24 12.0 5.4 clear calm none 0 11 5,300 high
21

Appendix 4. —Continued

Flight 

No. Date Unit ID

Polygon 

ID(s)

Unit 

area 

(km2)

Survey 

duration

(min)

Survey 

intensity

(min/

km2)

Sky

condition Winds Ppt

Cloud 

cover

(percent)

Temp 

(oC)

Elevation

(ft) Illumination

12 7/23/2011 81E 81E 4.71 25.6 5.4 clear calm none 0 11 5,500 high

12 7/23/2011 83 83 5.99 27.6 4.6 clear calm none 0 11 5,500 high

12 7/23/2011 87 87,88 2.04 8.2 4.0 clear calm none 0 11 5,500 high

13 7/24/2011 141 141,142 3.76 24.1 6.4 clear light none 0 15 5,000 flat

13 7/24/2011 131 131 6.66 30.7 4.6 clear light none 0 20 4,800 high

13 7/24/2011 117 117 1.74 7.1 4.1 clear light none 0 20 5,500 high

14 7/24/2011 76 76 5.37 29.0 5.4 clear light none 0 high

14 7/24/2011 73E 73E 4.44 19.5 4.4 clear light none 30 high

14 7/24/2011 73W 73W 3.01 26.0 8.6 mostly clear light none 30 20 4,800 high

15 7/24/2011 65 65W 3.99 20.0 5.0 clear light none 10 20 6,000 high

15 7/24/2011 64 64 4.13 11.9 2.9 mostly clear light none 20 20 6,000 high

15 7/24/2011 41 41 5.65 13.7 2.4 mostly clear light none 3 20 6,000 high

16 7/25/2011 54 54 5.12 15.0 2.9 mostly cloudy calm light 65 14 6,200 flat

16 7/25/2011 55 55 5.08 18.2 3.6 mostly cloudy calm none 45 14 6,200 flat

16 7/25/2011 50 50 5.00 27.2 5.4 mostly cloudy calm none 80 12 6,000 flat

16 7/25/2011 22 22 4.93 15.1 3.1 mostly cloudy calm none 70 12 6,000 flat

17 7/25/2011 48 48 6.87 23.0 3.3 mostly cloudy light none 85 14 5,100 flat

17 7/25/2011 72 72 6.49 30.2 4.7 mostly cloudy light none 90 15 5,600 flat

17 7/25/2011 117 118 3.30 12.0 3.6 mostly cloudy light none 95 15 4800 flat

18 7/25/2011 1 1 - 13 20.41 74.5 3.7 mostly cloudy light none 60 16 4800 flat

19 7/25/2011 132 132 3.73 19.6 5.3 overcast moderate none 85 12 5600 flat
22

Appendix 5. Raw Counts of Mountain Goats by Survey Unit, Olympic 

Mountains, Washington, 2011. 

[For each unit, the number of mountain goats observed within the portion of the survey unit below 1,520 m elevation 

is noted in parentheses. Stratum: SMC, Special Management Concern; H, high density; M, medium density; L, low 

density]

Stratum Survey unit Survey unit name Total Adults Kids

SMC 1 Klahhane Total Count 11 8 3

H 69 Chimney Total Count 27 (1) 24 3

H 93 Mount Skokomish 13 11 2

H 115 Seattle 1 (1) 1 0

H 125 Olympus Total Count 74 (9) 58 16

H 129 Glacier Meadows 4 3 1

H 127N Olympus Summit, North 11 (2) 8 3

H 127S Olympus Summit, South 0 0 0

H 131 Mount Childs 0 0 0

H 137 Carrie Total Count 25 23 2

H 141 Bogachiel Peak 0 0 0

M 48 Mount Fromme 0 0 0

M 54 Sunnybrook Meadows 0 0 0

M 55 Home Lake 0 0 0

M 65 Mount Constance, West 0 0 0

M 72 Eel 0 0 0

M 73E Mount Anderson, East 0 0 0

M 73W Mount Anderson, West 15 12 3

M 76 Diamond South 5 3 2

M 81E Mount Steel, East 11 11 0

M 83 LaCrosse 0 0 0

M 91 Mount Gladys 0 0 0

M 94 Mount Stone 0 0 0

M 95 Mount Hopper 0 0 0

M 97 Mount Bretherton 0 0 0

M 116E Mount Queets, East 0 0 0

M 117 Dana 0 0 0

M 122 Valhallas, North 11 (5) 11 0

M 123 Humes Glacier 6 (6) 3 3

M 124 Mount Barnes 1 1 0

M 130 Mount Mathias 0 0 0

M 132 Ludden Peak 0 0 0

M 135 Scott/Dodger 1 1 0

L 22 Badger 0 0 0

L 41 Grey Wolf North 0 0 0

L 50 Wellesley Peak 1 1 0

L 64 The Gargoyles 0 0 0

L 87 Jupiter 0 0 0

L 140 Mount Fitzhenry 0 0 0

TOTALS 217 179 38
Publishing support provided by the U.S. Geological Survey

 Publishing Network, Tacoma Publishing Service Center

For more information concerning the research in this report, contact the

 Director, Forest and Rangeland Ecosystem Science Center

 U.S. Geological Survey

 777 NW 9th Street, Suite 400

 Corvallis, Oregon, 97330

 http://fresc.usgs.gov/
Jenkins and others—Mountain Goat Abundance and Population Trends in the Olympic Mountains, Washington, 2011—Open-File Report 2011-1313