Summary

Description

Management goals for Sitka blacktailed deer Odocoileus hemionus sitkensis at Kodiak National Wildlife Refuge are to minimize deer impacts to native flora and fauna while maintaining subsistence harvest opportunities. Accomplishment of these goals requires statisticallyrobust estimates of deer abundance. We estimated deer abundances in nonforested, nonmountainous habitats of southern Kodiak Island using double observer markrecapture distance sampling applied to traditional linetransect aerial counts. We conducted two replicate surveys in nonforested grassland, tundra, and shrub habitats at the Aliulik Peninsula, Olga Flats, and the Ayukulik River valley of Kodiak Island, between 16 May and 21 May 2014. We observed an average of 92 deersurvey replicate, with an average deer group size of 1.73 deergroup. After correcting for estimated deer detection, which accounted for imperfect detection on the transect line, distance to the observer, habitat types, and deer group size effects, we estimated 432 deer SE65.70 occupied the survey area at a density of 0.74 deerkm2 SE0.12. Observer detection on the transect line was 0.93 SE0.02. Deer densities at the Aliulik Peninsula 0.86, SE0.16 were 62 higher than during a 2012 survey 0.53 deerkm2, SE0.07. We opportunistically counted deer carcasses and other wildlife bears, swans, and whale carcasses, which could be used as an index of annual changes in their abundances. This survey provides the first statisticallyrobust means of indexing annual trends in deer densities and abundances on Kodiak Island.