Research Projects

Relative risk of attracting coyotes or feral dogs to desert tortoises using humans and human-dog teams in surveys

PI: Mary Cablk

Project Period: October 2003 - December 2004

Funded by: Marine Corps Air Ground Combat Center, Twenty-nine Palms, CA

Right: Desert Tortoise

Keywords: Gopherus agassizii, Mojave Desert Tortoise, K9

Project Approach

The Desert Tortoise (Gopherus agassizii) occurs throughout the Mojave Desert of California, including the Marine Corps Air Ground Combat Center (MCAGCC), Twentynine Palms, CA. A large, multi-agency project is ongoing to test the efficacy of trained scent detector dogs in conducting desert tortoise presence/absence and density/distribution surveys. The project proposed here is intended to contribute to this larger project effort. Specifically, the proposed project will address an issue of concern to and suggested by the U.S. Fish and Wildlife Service (FWS) to determine if the use, meaning presence, of domestic dog/handler teams to detect tortoises results in attracting native and non-native predators (i.e. coyotes, feral dogs). The objective is to determine if coyotes and/or feral dogs are more attracted to locations where people conduct field surveys compared to locations where people and dogs conduct surveys. There are two elements within this objective; the first element is to determine simple presence/absence (P/A) as indicated by tracks and/or scat. Presence of coyote and/or feral dog at locations where people and people plus dogs are conducting concentrated work may indicate an elevated interest in that particular location. Defecation or other marking behavior may indicate a territorial response rather than a predatory reaction. Comparing results between locations without any scent, locations with only human scent, and locations with both human and dog scent will provide basic information as to the degree of relative risk either survey method poses of drawing the attention of a potential predator. The second element of interest is the length of time between the human or human/dog presence and the recorded P/A if any, of either coyote or feral dog. The greater the length of time between investigation of human or human/dog presence by the coyote or feral dog, the less likely a tortoise is to be in the same location where the survey activity located that tortoise. Thus, the likelihood of an interaction between tortoise and coyote or feral dog decreases. The combination of both initial attraction and time to investigation therefore comprises the attraction-risk metric.

Objectives

The objective is to determine if coyotes and/or feral dogs are more attracted to locations where people conduct field surveys compared to locations where people and dogs conduct surveys. There are two elements within this objective; the first element is to determine simple presence/absence as indicated by tracks and/or scat. Presence of coyote and/or feral dog at locations where people and people plus dogs are conducting concentrated work, such as taking measurements and biological data of a located desert tortoise may indicate an elevated interest in that particular location. Defecation or other marking behavior may indicate a territorial response rather than a predatory reaction.