Taylor’s checkerspot (Euphydryas editha taylori) Captive Rearing and Reintroduction: South Puget Sound, Washington, 2015-2016.

This report summarizes captive-rearing work conducted in May 2015-May 2016, and reintroduction work from July 2015-July 2016. The captive rearing section borrows heavily from annual reports produced by the Oregon Zoo (Lewis et al. 2016) and Mission Creek (Dorman et al. 2016) programs. Postdiapause larval Taylor’s checkerspots were released at two existing reintroduction sites in 2016: Scatter Creek South (SCS; initiated in 2007) and Glacial Heritage Preserve (GHP; initiated in 2012). In addition, adults and prediapause larvae were released at Training Area 7 South (TA7S; initiated 2014). Monitoring for establishment continued at Scatter Creek South and Range 50 (R50; initiated in 2009). Staff from Joint Base Lewis-McChord (JBLM) took over monitoring at Pacemaker (PCM; initiated in 2012), which had no sightings in 2015. A total of 10,317 eggs were produced at the two captive rearing facilities between 20 April and 21 May 2015. A total of 1,658 postdiapause larvae were released at SCS on 23 February 2016. On 25 February 2016, a total of 2,029 larvae were released at Glacial Heritage Preserve. Of the 3,687 larvae released, 2,377 were offspring of wild females, 1,210 were offspring of captive-mated females. On 2 May and 12 May 2016, 210 adult Taylor’s checkerspots (153 females and 60 males) from the Oregon Zoo were released on 2 May 2016 at TA7S. In addition, 20 wild females from R76 that were brought to the University of Washington for oviposition were released at TA7S once egg targets were met; for a total of 231 adults released.

We used distance sampling to quantify daily population density, daily population size, and to illustrate the distribution of adults at four reintroduction sites (R50, SCS, GHP and TA7S) and at R76 (source site). A combined total of 7,402 checkerspots were counted during distance surveys in 2016, with the greatest number observed at R50. Peak counts occurred on 20-21 April (Table 15), but encounter rates varied among sites, with twice as many butterflies observed at R50 (0.126 checkerspots/m) compared to SCS (0.069/m). Numbers were substantially lower at both R76 (0.024/m for transects 1-16; 0.014/m for transects 1-12) and GHP (0.013/m) compared to both R50 and SCS. Very low numbers and the apparent dispersal of the R76 population make it unlikely we can collect the requisite adults needed for captive rearing and reintroduction in 2017. Reasons for these trends are unclear but habitat condition and/or military training impacts cannot be ruled out as primary causes since we do not see similar trends at other sites. Either way, decline or loss of the R76 population could endanger both reintroduction and recovery efforts underway in the Puget lowlands.