Weak effects of geolocators on small birds: A meta-analysis controlled for phylogeny and publication bias

Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light-level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta-analyses did not evaluate unpublished data and impact of multiple life-history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially. We quantitatively reviewed 549 records extracted from 74 published and 48 unpublished studies on over 7,800 tagged and 17,800 control individuals to examine the effects of geolocator tagging on small bird species (body mass <100 g). We calculated the effect of tagging on apparent survival, condition, phenology and breeding performance and identified the most important predictors of the magnitude of effect sizes. Even though the effects were not statistically significant in phylogenetically controlled models, we found a weak negative impact of geolocators on apparent survival. The negative effect on apparent survival was stronger with increasing relative load of the device and with geolocators attached using elastic harnesses. Moreover, tagging effects were stronger in smaller species. In conclusion, we found a weak effect on apparent survival of tagged birds and managed to pinpoint key aspects and drivers of tagging effects. We provide recommendations for establishing matched control group for proper effect size assessment in future studies and outline various aspects of tagging that need further investigation. Finally, our results encourage further use of geolocators on small bird species but the ethical aspects and scientific benefits should always be considered.

Fil: Vrojtech, Brlik. Czech Academy of Sciences. Institute of Vertebrate Biology; República Checa. Charles University. Faculty of Science. Department of Ecology; República Checa

Fil: Kolecek, Jaroslav. Czech Academy of Sciences. Institute of Vertebrate Biology; República Checa

Fil: Burgess, Malcolm. Royal Society for the Protection of Birds. Centre for Conservation Science; Reino Unido

Fil: Hahn, Steffen. Swiss Ornithological Institute. Bird Migration Department; Suiza

Fil: Humple, Diana. Point Blue Conservation Science; Estados Unidos

Fil: Krist, Milos. Palacky University. Faculty of Science. Department of Zoology; República Checa

Fil: Ouwehand, Janne. University of Groningen. Groningen Institute for Evolucionary Life Sciences. Conservation Ecology Group; Países Bajos

Fil: Weiser, Emily. Kansas State University. Division of Biology; Estados Unidos. United States Geological Survey; Estados Unidos

Fil: Adamík, Peter. Palacky University. Faculty of Science. Department of Zoology; República Checa. Museum of Natural History; República Checa

Fil: Alves, José. Universidade de Aveiro. Department of Biology and Centre for Environmental Sciences Studies; Portugal. University of Iceland. South Iceland Research Centre; Islandia

Fil: Arlt, Debora. Swedish University of Agricultural Sciences. Department of Ecology; Suecia

Fil: Barisic, Sanja. Croatian Academy of Sciences and Arts. Institute of Ornitology; Croacia

Fil: Becker, Detlef. Museum Heineanum; Alemania

Fil: Belda, Eduardo. Universidad Politécnica de Valencia; España

Fil: Beran, Václav. Municipal Museum of Ústí Nad Labem; República Checa. Palacky University. Faculty of Science. Department of Zoology; República Checa. ALKA Wildlife o.p.s; República Checa

Fil: Both, Christiaan. University of Groningen; Países Bajos

Fil: Bravo, Susana Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina

Fil: Briedis, Martins. Swiss Ornithological Institute. Bird Migration Department; Suiza

Fil: Chutny, Bohumir. No especifica;

Fil: Cikovic, Davor. Croatian Academy of Sciences and Arts. Institute of Ornitology; Croacia

Fil: Cooper, Nathan. National Zoological Park. Smithsonian Conservation Biology Institute. Migratory Bird Center; Estados Unidos

Fil: Costa, Joana. Universidade de Aveiro; Portugal

Fil: Cueto, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina

Fil: Emmenegger, Tamara. Swiss Ornithological Institute. Bird Migration Department; Suecia

Fil: Fraser, Kevin. University of Manitoba; Canadá

Fil: Gilg, Olivier. Groupe de recherche en Ecologie Arctique; Francia. Universite de Bourgogne; Francia

Fil: Guerrero, Marina. Servicio de Jardines; España

Fil: Hallworth, Michael. Smithsonian Conservation Biology Institute; Estados Unidos

Fil: Hewson, Chris. British Trust for Ornithology; Reino Unido

Fil: Jiguet, Frédéric. Muséum National d'Histoire Naturelle; Francia

Fil: Johnson, James. Migratory Bird Management, Alaska; Estados Unidos

Fil: Kelly, Tosha. Western University; Canadá

Fil: Kishkinev, Dmitry. Bangor University; Reino Unido

Fil: Leconte, Michel. Quartier Du Caü; Francia

Fil: Lislevand, Terje. University of Bergen; Noruega

Fil: Lisovski, Simeon. Swiss Ornithological Institute. Bird Migration Department; Suiza

Fil: López, Cosme. Universidad de Sevilla; España

Fil: McFarland, Kent. Vermont Center for Ecostudies; Estados Unidos

Fil: Marra, Peter. Smithsonian Conservation Biology Institute; Suiza

Fil: Matsuoka, Steven. United States Geological Survey; Estados Unidos

Fil: Matyjasiak, Piotr. Cardinal Stefan Wyszyński University; Polonia

Fil: Meier, Christoph. Swiss Ornithological Institute. Bird Migration Department; Suiza

Fil: Metzger, Benjamin. No especifíca;

Fil: Monrós, Juan. Universidad de Valencia; España

Fil: Neumann, Roland. No especifica;

Fil: Newman, Amy. University of Guelph; Canadá

Fil: Norris, Ryan. University of Guelph; Canadá

Fil: Pärt, Tomas. University of Agricultural Sciences; Suecia

Fil: Pavel, Václav. Palacký University; República Checa

Fil: Perlut, Noah. University of New England; Estados Unidos

Fil: Piha, Markus. University of Helsinki; Finlandia

Fil: Reneerkens, Jeroen. Palacký University; República Checa

Fil: Rimmer, Christopher. Vermont Center for Ecostudies; Estados Unidos

Fil: Roberto Charron, Amélie. University of Manitoba; Canadá

Fil: Scandolara, Chiara. Swiss Ornithological Institute; Suecia

Fil: Sokolova, Natalia. Ural Branch Russian Academy of Sciences; Rusia

Fil: Takenaka, Makiko. Tokai University; Japón

Fil: Tolkmitt, Dirk. No especifica;

Fil: van Oosten, Herman. Radboud Universiteit Nijmegen; Países Bajos

Fil: Wellbrock, Arndt. University of Siegen; Alemania

Fil: Wheeler, Hazel. Wildlife Preservation Canada; Canadá

Fil: van der Winden, Jan. Ecology Research and Consultancy; Países Bajos

Fil: Witte, Klaudia. University of Siegen; Alemania

Fil: Woodworth, Bradley. University of Queensland; Australia

Fil: Prochazka, Petr. Czech Academy of Sciences; República Checa