Washington Ground Squirrel Translocation Summary 2018 Sheri Whitfield, Wildlife Biologist

This summary includes annual monitoring efforts of Washington ground squirrels at two locations where this species has been released on the Columbia National Wildlife Refuge (NWR) near Othello, Washington (Map 1). The Barton road site was established in 2016 and monitored during 2017 and 2018 for squirrel presence and reproduction. This site was an effort to move Washington ground squirrels from the golf course at Sage Hills north of Othello on Highway 17. The ownership and management had recently changed at the golf course making squirrels more vulnerable in that area, and moving them to the refuge was intended to protect them and establish a population where they would not be persecuted.

This report also addresses the construction, translocation and monitoring efforts at the Morgan Lake road WA ground squirrel reintroduction enclosures. This site was created during 2018. The Morgan lake road site was built to hold squirrels that had potential to be displaced by road construction along Washington State Highway 17 north of Othello. The Department of Transportation planned construction along a portion of the highway where Washington ground squirrels were known to be living within the road right of way. The Morgan lake road site was built because of this eminent threat to the squirrels along Highway 17. Again moving them to the refuge was an effort to establish squirrels in a site where they would be less vulnerable.

Map 1. Location of Washington ground squirrel enclosures at Columbia NWR.

INTRODUCTION

The Washington ground squirrel (Urocitellus washingtoni) is a small fossorial mammal endemic to the shrub and grasslands of the Columbia Basin. This ground squirrel species is found in silt loam soils found in high quality shrub-steppe habitat containing a mixture of bunch grasses and forbs. The conversion of habitat for alternative uses (i.e. agriculture) has resulted in considerable habitat loss and fragmentation causing significant population declines (Germaine et al. 2007). The ground squirrel is candidate for listing as a Threatened species in the State of Washington.

Records indicate that Washington ground squirrels currently occupy a much narrower estimated range than this species occupied historically. Columbia NWR was identified as a site to attempt a soft release of the ground squirrel to expand their current range, and to provide a habitat where the squirrels would not be persecuted or vulnerable to habitat destruction. Past translocations using a smaller enclosure and without the construction of underground artificial burrows have been unsuccessful. The current release enclosure area encompasses 2.5 acres including six underground burrow structures and predator fence to mitigate for issues identified from previous squirrel releases. The release enclosure at the refuge was selected based on soil depth, soil type and relative shrub cover. Squirrels rapidly adapted to the site within the enclosure, using much of the area within the site and also breached the confines of the fence and dispersed to areas adjacent to the enclosure. Monitoring during 2018 will be the second year of monitoring, monitoring was conducted during 2017 and an annual report was produced for that season.

BARTON ROAD (2016) GROUND SQUIRREL ENCLOSURE

Monitoring Objectives 2018

 Monitor ground squirrel population  Investigate ground squirrel reproductive success  Monitor predator activity at reintroduction site  Determine period of activity and onset of estivation/hibernation

On January 24, 2018, USFWS personnel deployed six trail cameras to monitor the activity of the Washington ground squirrel enclosure located on Barton Road at Columbia NWR (Map 2). The cameras are used to monitor ground squirrel activity, reproductive success and predator activity.

Map 2. Points on map indicate location of trail camera during monitoring.

Weekly visits to the site recorded squirrel vocalizations and signs of squirrel activities including: foraging, trails and fresh digging or tracks. Washington ground squirrels have an annual cycle characterized by a relatively short active period when activities such as foraging, social behavior, and reproduction occur, followed by a relatively long period of estivation/hibernation.

Year 2 monitoring efforts in 2018, determined squirrels continued to use the underground structures consistently at the release enclosure. Six trail cameras were set at artificial burrow sites to record activity of adults and potential pup emergence and to ensure adequate viewing and documentation of squirrel activities. Ground squirrels are easily detected by their high-pitched whistle or alarm call. Ground squirrels’ alarm calls were heard on various occasions during monitoring efforts.

Trail camera data captured adult ground squirrel emergence on January 25, 2018. USFWS staff stated Columbia NWR experienced a mild winter, compared to the 2016 winter, so it is important to note that ground squirrel emergence may have occurred prior to January 25 (Figure 1).

Figure 1. Washington ground squirrel trail camera earliest emergence on January 25, 2018.

Excavated natural burrows were located within and outside of the enclosure. These excavated burrows were clear of debris and had fresh diggings and tracks (Figure 2 & 3).

Figure 2. WA ground squirrel natural burrow excavated outside the enclosure. Pocket knife for scale.

Figure 3. Excavated ground squirrel burrow inside the enclosure.

Trailing between the excavated and artificial burrows is evident as well, including fresh tracks and squirrel scat near burrow entrances. The picture (Figure 4) below demonstrate the trailing activity used by ground squirrels inside the enclosure.

Figure 4. Ground squirrel trailing is evident inside the enclosure.

Ground squirrels captured on trail cameras demonstrate a variety behavioral activities such as standing or sitting in an “alert type posture” when scanning for predators, socializing and foraging as shown in Figures 5, 6, and 7.

Figure 5. Alert posture.

Figure 6. Foraging.

Figure 7. Socializing.

Washington Ground Squirrel - Adults

In 2016, 34 ground squirrels were tagged and released into the Barton Road enclosure. Trail camera footage captured three ground squirrels with ear tags from the 2016 trapping efforts on camera 2, 3 and 4 (Figure 8, 9, and 10). This indicates that the squirrels have been able to persist in this location for at least two seasons.

Figure 8. WA ground squirrel displaying ear tag at camera 2.

Figure 9. WA ground squirrel displaying ear tag at camera 3.

Figure 10. WA ground squirrel displaying ear tag at camera 4.

Washington Ground Squirrel - Pups

One of the monitoring objectives is to determine reproductive success within the enclosure. Ground squirrel litter size averages between 4-9 pups with a gestation period of about 4-5 weeks. Trail camera footage captured lactating females (Figure 11, 12, and 13) and pups (Figure 14, 15, and 16) with the earliest pup emergence detection occurring on March 15, 2018.

Figure 11. Adult lactating female at artificial burrow.

Figure 12. Adult lactating female documented on camera 4.

Figure 13. Female ground squirrel shows signs of lactating documented on camera 1.

Figure 14. Ground squirrel pups at artificial burrow.

Figure 15. Washington ground squirrel adult female and pup.

Figure 16. Ground squirrel pups at burrow entrance.

Typically, males of most ground squirrel species disperse as juveniles before their first winter and 100% disperse by the end of their yearling summer (Feldhamer et. al 2003).

The graph below provides the number of days per camera of at least one squirrel (i.e. adult, juvenile) visible on camera footage between January 24 - July 5, 2018. All six-trail cameras at the enclosure were removed on July 5, 2018. Note: Between June 17 – July 5, 2018 no visible ground squirrel activity occurred on trail camera footage.

Graph 1. Number of times a ground squirrel was visible on each of the six trail cameras. There were a total of 162 days when the cameras were active and available to record squirrel activity. Number of times January - July 2018 at least one squirrel was observed on each of the six trail cameras

140 128 117 117 118 120 109 100 100

80

60

40

20

0 Camera 1 Camera 2 Camera 3 Camera 4 Camera 5 Camera 6

Graph 2. Number of ground squirrels observed daily on each of the six cameras. Ground Squirrels Observed Daily Per Camera 7

6

5

4

3

2

1

0

Camera 1 Camera 2 Camera 3 Camera 4 Camera 5 Camera 6

Graph 3. Total number of ground squirrels observed each day. Total of squirrels observed in all 6 cameras within the enclosure. Total # Of Squirrels Observed Each Day 25

20

15

10

5

0

Predator Monitoring

In addition, predator activity in and around the enclosures was monitored during weekly visits. Active ground squirrels are highly vulnerable to numerous predators including the American badger (Taxidea taxus) and coyote (Canis latrans). On June 13, two potential badger burrows on the outside perimeter of the squirrel enclosure were photographed and GPS’d. Coyote scat has been observed along the outside perimeter of the enclosure. Trail camera footage did not capture badger or coyote activity occurring inside the enclosure (Figure 17 and 18).

Figure 17. Potential badger burrow UTM 5189218N, 321251E

Figure 18. Potential badger burrow UTM 5819249N, 321252E

Estivation/Hibernation

The Washington ground squirrel is diurnal (active during daylight hours), and spends much of the year underground. Trail camera footage captured the majority of ground squirrel activity in the morning and early afternoon, when temperatures were typically cooler. Trail cameras used are light sensitive and do not record data during overnight hours. Usually, adults return to their burrow for estivation by late May to early June and juveniles return a month later (Rickart and Yensen 1991).

The final recorded ground squirrel observation occurred on June 16, 2018 (Figure 19). Trail cameras were removed from this release enclosure on July 5, 2018.

Figure 19. Last observation of ground squirrel monitoring captured on June 16, 2018.

Supplemental Feeding

Ground squirrels are primarily, but not exclusively herbivorous. Washington ground squirrels eat a wide variety of foods including succulent forb and grass stems, buds, leaves, flowers, roots, bulbs, and seeds (Greene 1999). Native plants appear important to Washington ground squirrels, and bluegrass (Poa sp.) is a major dietary component. Nonnative cheatgrass is also a part of their diet even though it is considered to be an unstable food source because the amount of forage it produces is highly variable depending upon annual precipitation (Tarifa and Yensen 2004 and Vander Haegen et. al. 2001).

Vegetation (forbs and grass) within the Barton Road enclosure was observed weekly to ensure adequate forage availability for ground squirrels. Grasses identified within the enclosure include cheatgrass (Bromus tectorum) and Sandberg bluegrass (Poa secunda) as the dominant grasses. It was documented, however, as compared to 2017; forbs inside the enclosure were extremely limited or nonexistent.

The cheatgrass inside the enclosure cured very early in spring of 2018. In 2017, supplemental feeding was conducted in early June; this year however, supplemental feeding started on May 3, and concluded on June 28, 2018. Ground squirrels were fed a mixture of carrots and black oil sunflower seeds (Figure 20 and 21).

Figure 20. Ground squirrel feeding on carrots.

Figure 21. Supplemental feeding of Washington ground squirrel.

Supplemental water was not provided in release enclosure to eliminate potential for increased disease. Ground squirrels are active (i.e. forage) during spring months when the availability of green plant material, as a source of water, is high (Rogers and Gano 1980). Ground squirrels will use pools of standing water when available, however; they can easily live on metabolic water and moisture from vegetation (Walsberg 2000).

Habitat Improvement

In the fall 2018, USFWS personnel will be planting prairie clover (Dalea ornata) at both Washington ground squirrel enclosures.

MORGAN LAKE ROAD (2018) GROUND SQUIRREL ENCLOSURE

Introduction

In January 2018, the Washington Department of Fish and Wildlife (WDFW) contacted the Mid- Columbia River office indicating a need to trap and move WA ground squirrels from the rights- of-way along Highway 17 near the Sage Hills golf course. According to WDFW, expansion of Highway 17 would occur through an existing ground squirrel population. Release of all trapped ground squirrels would occur on the Columbia NWR. Since the ground squirrel enclosure (located on Barton Road, Columbia NWR) has successfully met the 2018 objectives, (i.e. reproduction), USFWS personnel determined the best course of action would be to construct a completely new WA ground squirrel reintroduction area. The site selected because of existing soil depth, soil type and vegetation cover. Below is a map of the most recent WA ground squirrel release enclosure on Columbia NWR (Map 3).

Map 3. Location of 2018 Washington ground squirrel enclosure on Columbia NWR.

Construction Timeline

Construction of a new WA ground squirrel release enclosure at Columbia NEW occurred the week of February 12 – 15, 2018. FWS refuge staff, including WDFW and two volunteers constructed eight artificial burrows and installed fencing around 2.24 acres using the same materials during construction of the 2016 (Barton road) release enclosure. All artificial burrows were constructed using the methods outlined in the “Users Guide to Installation of Artificial Burrows for Burrowing Owls (Johnson et. al 2010). Materials (i.e. barrels, tubing) and small backhoe provided by WDWF Ephrata regional office for use of installation of artificial burrows. The only difference being that no wire or protection was placed on the bottom of the burrow chamber; this allows the squirrels to dig out of the underground structure and to create their own tunnels.

The fence was constructed surrounding the new release enclosure ensures the ground squirrels some protection from predators (i.e. coyote, badgers) and from immediately dispersing from the release enclosure (Figure 22 and 23).

Figure 22. Fence construction at new ground squirrel release enclosure.

Figure 23. Picture of completed fence at new site.

Vegetation at the new site is dominated with bluebunch wheatgrass (Pseudoroegneria spicata) and basin wild rye (Elymus cinereus), however; no shrubs are present. Shrubs provide hiding cover for the ground squirrel from aerial predators (i.e. raptors). Artificial tunnel systems were created by BFI on February 22, using a “verminator” throughout the site (Figure 24). The tunnels are approximately 2” in diameter and between 6” and 8” below the ground surface. Because the area did not contain existing shrub cover, these tunnels provided the ground squirrels an additional hiding cover source from aerial predators.

Figure 24. Diagram of Verminator tunnel design.

Seeding & Planting

A mixture of native forb and grass seed, provided by WDFW, was broadcast by hand on February 15 at each of the eight artificial burrow locations and along the fenceline. The forb mixture was a combination of arrowleaf balsamroot (Balsamorhiza sagittata), parsnipflower buckwheat (Eriogonum heracleoides), alpine penstemon (Penstemon venustus) and common yarrow (Achillea millefolium). Grass seed mixture included bluebunch wheatgrass, thickspike wheatgrass (Elymus lanceolatus), Indian ricegrass (Oryzopsis hymenoides), bottlebrush squirreltail (Elymus elymoides), sand dropseed (Sporobolus cryptandrus), and sandberg bluegrass (Poa secunda).

On February 21, 2018, 40 Wyoming sagebrush (Artemisia tridentate wyomingensis) and 24 basin wild rye purchased from BFI, were planted throughout the site by USFWS personnel.

Trapping

WDFW and USFWS personnel conducted ground squirrel trapping efforts at Sage Hills golf course twice in the spring of 2018.

During the week of March 5-9, 2018 WDFW personnel began ground squirrel trapping efforts using Tomahawk live traps 1.5”x 6”x 6”. Trapping of ground squirrels focused on male and female adult ground squirrels prior to pup birth. No pre-baiting was conducted during this week and no ground squirrels were captured. WDFW would commence ground squirrel trapping in either late April or early May 2018, after the emergence of ground squirrel pups.

Thirty-four Tomahawk live trap pre-baiting began on April 24 – 29, 2018 with raw peanuts and carrots. During pre-baiting and trapping efforts, a FWS volunteer lived on site (i.e. Sage Hills golf course RV park) to ensure the trapping area (i.e. traps, bait) remained undisturbed by the public.

Live trapping of ground squirrels from Sage Hills golf course occurred April 30 & May 1, 2018. Trap start times occurred around 7:00am each morning and completed by 11:00am. Weather conditions were favorable both trap days. Morning temperatures at or near 40 degrees Fahrenheit with a day high ranging from 65 – 72 degrees Fahrenheit. Trapping efforts were each day by 11:00am. All traps were checked approximately every 30 minutes.

After capture in the live traps, ground squirrels were placed inside a pillowcase, marked with the trap ID number and time of capture. Caution was taken to reduce sound levels around the processing area to reduce stress on trapped ground squirrels. Individual ground squirrels were ear tagged with a unique number on both ears. The trap number, ear tag number, mass, sex, age, trap time, and any comments were recorded on a data sheet (Figure 25 and 26). All individual ground squirrels were released into enclosure on the same day they were captured.

Figure 25. Washington ground squirrel in tomahawk trap.

Figure 26. Ear tagging a Washington ground squirrel.

Once at the release enclosure, squirrels were carefully placed into an artificial burrow location based on sex, age and trap area. It was assumed that the closer the proximity of individual captured, the greater the level of kinship. One to two females or one to two males placed into each burrow site. The burrow tubes were blocked and all ground squirrels were held a minimum one hour inside the artificial burrow to increase fidelity to the release enclosure, reduce stress and reduce immediate dispersal (Figure 27).

Figure 27. Releasing ground squirrels at new reintroduction enclosure.

Fifty-seven individual ground squirrels were trapped and ear tagged from the Sage Hills golf course (Table 1). Of those ground squirrels, 22 males, 27 females and 3 unknowns were released at the Columbia NWR. One mortality of a small juvenile ground squirrel occurred while waiting to be processed. Another ground squirrel very small was not processed, but released on the refuge. Three female ground squirrels trapped appeared to still be nursing. These ground squirrels were re-released back in the trapping area. Two ground squirrels were recaptures from the 2016 trapping efforts. Both ground squirrels were released at the new enclosure.

On May 10, 2018, WDFW released three ground squirrels, trapped from the Sagebrush Flats pygmy rabbit enclosure, into the reintroduction enclosure at Columbia NWR.

All dated entered and located at N:/Columbia/Biology/Washington Ground Squirrel – Columbia NWR/Squirrel_Ear_TagDATA.xlsx. 2018 Trapping

Table 1. Summary of male and female ground squirrels trapped. Location Males Females Unknown Total Sage Hills Golf Course 22 27 3 57 Sagebrush Flats PYRA Enclosure 2 1 3 TOTAL 24 28 3 60

Monitoring Objectives 2018

 Monitor ground squirrel population activity since reintroduction  Monitor predator activity at reintroduction site  Determine period of activity and onset of estivation/hibernation

Three trail cameras deployed on April 30, 2018 at artificial burrow enclosure to record ground squirrel activity. Monitoring at the new location, included vocalizations, scat and observations. Trail cameras located at artificial burrow ensure adequate viewing and documentation of squirrel activities (Figure 28, 29 & 30). Note: At times monitoring trail camera footage at the new site was difficult due to the density of grasses.

Figure 28. Monitoring squirrel activity at new release enclosure.

Figure 29. Monitoring ground squirrels at new release enclosure.

Figure 30. Monitoring ground squirrels at new release enclosure.

Predator Monitoring

After ground squirrel reintroduction, and throughout the ground squirrel monitoring efforts, trail camera footage did not indicate any badger or coyote activity within or outside the enclosure. However, there is no active monitoring for predation by raptors in this area.

Estivation/Hibernation

Dormancy begins between May and July, and depends on age and sex (Burt and Grossenheider 1976; Hall and Kelson 1959). Ground squirrel estivation (i.e. dormancy) appears to be directly correlated with the amount of food available (Alcorn 1940). It is assumed that the ground squirrels remained active into July because they had available food (i.e. native grasses, supplemental feeding). Ground squirrels released at this enclosure could be investing extra time developing burrows in the area for later onset of estivation and hibernation. The additional food resources would provide ground squirrel adequate fat reserves prior to estivation/hibernation once burrow investments are successfully completed (Finger 2018). Trail camera footage captures ground squirrel activity occurring into early July 2018 (Figure 31).

Figure 31. Ground squirrel activity still occurring in early July.

The final recorded ground squirrel observation occurred on July 2, 2018 (Figure 32). Trail cameras were removed from the enclosure on July 18, 2018.

Figure 32. Last picture of ground squirrel for the monitoring season.

SUPPLEMENTAL FEEDING

Supplemental feeding at this enclosure site began on May 3, and concluded on July 12, 2018 after ground squirrels were no longer visible on camera footage. Ground squirrels at this location were also fed a mixture of carrots and black oil sunflower seeds (Figure 33 & 34). Providing supplemental water was not conducted for the reasons identified at the Barton road ground squirrel enclosure.

Figure 33. Supplemental food provided at new WA ground squirrel site.

Figure 34. Supplemental food provided at new WA ground squirrel site.

MANAGEMENT OBJECTIVES 2019 – BOTH RELEASE ENCLOSURES

 Deploy trail cameras at both WA ground squirrel enclosures late January or early February to determine earliest emergence of ground squirrels. (deployment would be determined on winter conditions).  Investigate ground squirrel reproductive success at both release enclosure.  Document predator activity at both ground squirrel sites (i.e. fresh burrows, digging) during weekly visits.  Conduct habitat transects to determine shrub, grass and forb cover.  Supplemental food – after available forage dries out.

LITERATURE

Alcorn, J. R. 1940. Life History Notes on the Piute Ground Squirrel. Journal of Mammalogy Volume 21, No. 2, pp. 160-170.

Burt, W. H., and R. P. Grossenheider. 1976. A Field Guide to the Mammals. Houton-Mifflin Company. Boston, Mass.

Feldhamer, G. A., B. C. Thompson, J. A. Chapman. 2003. Wild Mammals of North America – Biology, Management and Conservation Second Edition. The Johns Hopkins University Press.

Finger, R. 2018. Telephone conversation with Rich Finger, Washington Department of Fish and Wildlife.

Germaine, S. R. Finger, T. Owens. 2007. Landscape-Scale Habitat Associations of Washington Ground Squirrels (Spermophilus washingtoni) in Central Washington. Washington Department of Fish and Wildlife – Wildlife Program Science Division.

Green, E. 1999. Abundance and habitat associations of Washington ground squirrels in north- central Oregon. Oregon State University.

Hall, E.R., and K.R. Kelson. 1959. The Mammals of North America. Ronald Press Co. New York, N.Y.

Johnson, D. H., D. Gillis, M. A. Gregg, J. L. Rebholz, J. L. Lincer, and J. R. Belthoff. 2010. Users Guide to Installation of Artificial Burrows for Burrowing Owls. Tree Top Inc., Selah Washington. 34 pp.

Rickart, E.A, and Yensen, E. 1991. Spermophilus washingtoni. Mammalian Species p. 3-4.

Rogers, L. E, K. A. Gano. 1980. Townsend Ground Squirrel Diets in the Shrub-Steppe of Southcentral Washington. Journal of Range Management 33(6).

Tarifa, T. and E Yensen. 2004. Washington ground squirrel diets in relation to habitat condition and population status: supplemental report on livestock diets 2002. Unpublished report for Washington Department of Fish and Wildlife, Olympia, Washington.

Vander Haegen, W. M., S. M. McCorquodale, C. R. Peterson, G. A. Green, and E. Yensen. 2001. Wildlife communities of eastside shrubland and grassland habitats. P. 301.

Walsberg, G. E. 2000. Small Mammals in Hot Deserts: Some Generalizations Revisited. BioScience, Volume 50 Issue2.