RESEARCH ARTICLE


Analysis of California Condor (Gymnogyps californianus) Activity Using Satellite Telemetry Data



Christopher B. Cogan*, 1, Jesse D'Elia2, Ken Convery3, Joseph Brandt3, Tom Bulgerin4
1 Environmental Science and Resource Management Program, California State University Channel Islands, 1 University Dr. Camarillo, CA 93012, Redwood Mapping, 5416, USA
2 U.S. Fish and Wildlife Service, Pacific Regional Office, 911 NE 11th Avenue, 4th Floor, Portland, OR 97232, USA
3 U.S. Fish and Wildlife Service, Hopper Mountain National Wildlife Refuge Complex, P.O. Box 5839, Ventura, CA 93005, USA
4 Redwood Mapping 5416 Graham Hill Rd., Felton, CA 95018, USA


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© 2012 Cogan et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at Environmental Science and Re-source Management, California State University Channel Islands, 1 Univer-sity Dr., Camarillo, CA 93012, USA; Tel: 805-437-3319; Fax: 805-437-8864; E-mails: christopher.cogan@csuci.edu


Abstract

We describe new methods for quantifying specific in-situ activities of wildlife, in this case the endangered Cali-fornia condor (Gymnogyps californianus). These methods extract information from hundreds of thousands of temporally continuous and spatially explicit satellite telemetry reports. Visual observations and ground-based telemetry can provide behavioral data, although the information is often spatially and temporally limited and sample sizes can be small for wide-ranging species. Automated satellite telemetry offers continuous position reporting and unbiased spatial coverage, but to date has lacked thematic content such as the time, place, and duration of particular activities. Procedures developed for this study use a combination of models and geographic information systems (GIS) to identify condor transit flight, perch-ing, roosting, and nesting activity based only on hourly telemetry position reports. This approach combines the temporal and spatial advantages of automated telemetry with increased thematic quality from activity models. The analytical meth-ods were applied to 340,694 satellite-based position records from 51 California condors which were collected from June 2005 to April 2012. We identified 31,268 extended perch locations and an additional 15,483 overnight roost locations by translating basic location, speed, and time data into characterizations of bird activities. This approach correctly identified nine of the ten known nest sites occupied by condors outfitted with telemetry transmitters based only on the telemetry da-ta. The spatial locations of these activities were mapped using GIS. This represents a significant advantage over simple location and movement data normally associated with wildlife telemetry, and is applicable to a wide range of species.

Keywords: California condor, Satellite telemetry, GIS, Wildlife activity model.