Effects of geolocators on migratory birds: a meta-analysis

J. KOLEčEK, ; D. BECKER, ; M. BURGESS, ; N. COOPER,; V. BRLÍK1,; S.V. BARI?Ić, ; S.P. BRAVO, ; B. CHUTNÝ, ; P. PROCHÁZKA, ; D. ARLT, ; E.J. BELDA, ; D. ĆIKOVIć, ; V.R. CUETO,

Congreso; European Ornithological Union 2017 conference; 2017

Effects of light-level geolocators on migratory birds: a meta-analysis Petr Procházka1, Vojtěch Brlík1, Jaroslav Koleček1, Sanja Bari?ić2, Davor Ćiković2, Bohumír Chutný3, Tamara Emmenegger4, Kevin C. Fraser5, Steffen Hahn4, Diana L. Humple6, Tosha Kelly7, Dmitry Kishkinev8, Kent McFarland9, Václav Pavel10, Amélie Roberto-Charron5, Makiko Takenaka11, Dirk Tolkmitt12 1 Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, CZ-60365 Brno, Czech Republic2 Institute for Ornithology, Croatian Academy of Sciences and Arts, Gundulićeva 24, HR-10000 Zagreb, Croatia3 Malinová 27, CZ-10600 Praha 10, Czech Republic4 Department of Bird Migration, Swiss Ornithological Institute, Seerose 1, CH-6204 Sempach, Switzerland5 Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, R3T 2N2 Manitoba, Canada 6 PRBO Conservation Science, 3820 Cypress Drive no. 11, Petaluma, US-94954 California, USA7 Advanced Facility for Avian Research, Western University, 32 Wellington Drive, London, CA-N6G 4W4 Ontario, Canada8 School of Biological Sciences, Bangor University, Bangor, Gwynedd, UK9 Vermont Center for Ecostudies, PO Box 420, Norwich, Vermont US-05055, USA10 Department of Zoology and Laboratory of Ornithology, Palacký University, 17. listopadu 50, CZ-77146 Olomouc, Czech Republic11 Tokai University Sapporo Campus, Minamisawa 5-1-1-1, Minami-ku, Sapporo, Hokkaido JP-005-8601, Japan 12 Menckestraße 34, D-04155 Leipzig, GermanyKeywords: effect of tags, datalogger, migration, phenology, reproduction, survival, trackingAbstract (max. 250 words)The use of tracking devices is currently one of the most rapidly developing approaches to study bird migration. The recent advent of miniature light-level geolocators has led to a massive increase in the number of studies employing these devices, especially in small species, whose direct tracking was virtually impossible in the past. Although several meta-analytical and single-species primary studies have already examined the influence of geolocators on birds, their results are equivocal. Therefore, the evaluation of the effect of geolocators on birds clearly deserves more attention. Here, we test for the effect of geolocators on passerine and near-passerine birds by comparing return rates, body condition, phenology and breeding performance between around 7000 geolocator-tagged and 9000 control birds from more than 100 published studies. In addition, we include numerous unpublished data to evaluate a likely publication bias resulting from a lower probability of publishing studies where only few or no geolocators were retrieved. In the presentation, we will specifically examine the effects driven by species traits (such as body size and migration distance) and geolocator design. Our preliminary results showed a slight negative effect of geolocators on the return rate. Moreover, the effect tended to be stronger in unpublished compared with published studies. We also revealed that the information essential for rigorous testing for geolocator effects is often missing. We thus strongly recommend establishing procedural control groups in future geolocator studies.Synopsis for Twitter (max. 132 characters): Prochazka et al.: Meta-analysis of geolocator effects on return rates, body condition, phenology and breeding of migratory birds