Sika deer response to spotlight counts: implications for distance sampling of population density

Abstract

Sixteen spotlight counts were conducted at night between June and August 1998 in an area with a high density of sika deer(Cervus nippon) in Nikko National Park, Japan. Behavioral responses to spotlights were analyzed, and distance sampling techniques(DST) were used to estimate deer density. Deer behavior at the time of sighting and subsequent behavioral responses to spotlighting were recorded. Deer with perpendicular distance.LEQ.5m from the census route showed a flight ratio of 6.3% at the time of sighting, but deer>5m showed little flight response. Deer.LEQ.5m showed a relatively high flight response of 4.1-22.2% during census events, while deer further than 15m exhibited a low flight response. Our results show that the spotlight count method meets the basic theoretical assumptions of the DST