Optimizing the use of GPS devices to estimate home range and foraging areas in seabirds: The Imperial Shag (<i>Leucocarbo atriceps</i>) as a case study
Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II Ciudad Universitaria, C1428EGA, Ciudad Autónoma de Buenos Aires, Argentina
Flavio Quintana
Laboratorio de Ecología de Predadores Tope Marinos (LEPTOMAR), Instituto de Biología de Organismos Marinos (IBIOMAR), CONICET. Boulevard Brown 2915, U9120ACD, Puerto Madryn, Chubut, Argentina
Departamento de Ecología, Genética y Evolución & Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II Ciudad Universitaria, C1428EGA, Ciudad Autónoma de Buenos Aires, Argentina
birds Global Positioning System GPS home range area IBAs sample size
How to Cite
Gabelli-Suarez, Vera, Flavio Quintana, and Agustina Gómez-Laich. 2026. “Optimizing the Use of GPS Devices to Estimate Home Range and Foraging Areas in Seabirds: The Imperial Shag (Leucocarbo Atriceps) As a Case Study”. El Hornero 41 (1). https://doi.org/10.56178/eh.v41i1.1533.
Although GPS devices are widely used to delineate animal use areas, the sample size required to yield statistically robust estimates while minimizing animal welfare concerns is seldom assessed. In this study, we assessed how sample size (i.e., the number of individuals equipped with GPS devices) affects the accuracy of estimating both the total area of active use and the core foraging area of the Imperial Shag (Leucocarbo atriceps). We analyzed data from 140 breeding adults tracked over seven breeding seasons at Punta León (Chubut, Argentina). For each season, estimates of active use and core foraging areas were derived by progressively increasing the sample size from one to 20 individuals. Additionally, given sexual differences in foraging behavior, use and core foraging areas were estimated separately for females and males by progressively increasing sample sizes from one to 10 individuals per sex and year. On average, a minimum of 13 individuals was required to achieve < 5% increments in estimated area sizes. Tagging between 10 and 12 males and females was sufficient to estimate use and core foraging areas with an error below 5%. This study provides a straightforward approach to determine the minimum number of birds to tag, which can be adapted to other species with comparable movement patterns.
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