Anthropogenic activities threaten many wildlife populations by increasing mortality rates, making it crucial to identify the locations and causes of mortality to inform conservation actions. Technological advancements, such as GPS satellite tracking, enable precise recording of wildlife movements. High-resolution data from such devices can facilitate rapid carcass recovery and provide insights into the mortality causes of tagged individuals. Obtaining required information to determine these causes is complex, and standardized approaches can overcome these limitations. In this study, we introduce the LIFE EUROKITE Assessment Protocol (LEAP), a framework for determining the timing, locations, and causes of mortality in GPS-tagged birds. LEAP is a multifaceted approach that integrates: (1) GPS tracking data, (2) evidence from the mortality location (site investigation), and (3) necropsy results to derive the mortality cause and a corresponding certainty score. We supplement the detailed description of LEAP with case studies assessing its effectiveness. Using 329 deceased GPS-tagged red kites (Milvus milvus) we compared conditions of the carcasses processed using LEAP with 145 opportunistically collected raptor carcasses. We also show that LEAP improves carcass condition and therefore allows for higher quality necropsy results. Additionally, we assessed how availability among sources of information (tracking, site investigation and necropsy) influences the quality of mortality assessments. Applying LEAP with all data sources provided the highest quality assessments in 64% of cases. Some 35% of cases were of high quality without necropsy, instead drawing evidence only from tracking data and site investigations. Predation related mortality was less prevalent (11%) when relying on necropsy compared to cases without necropsy (36%), while poisoning showed the opposite trend. Furthermore, we provide guidelines and empirical examples of mortality assessments. Our standardized LEAP approach ensures the best use of all available information regarding mortality events in GPS-tagged birds and advances wildlife mortality research as a valuable tool for conservationists and wildlife managers.

Acción Por el Mundo Salvaje Villafranca Spain

Aix Marseille Univ CNRS IRD Avignon Univ Institut Méditerranéen de Biodiversité et d'Écologie Aix‑en‑Provence France

ANITRA System s r o Praha Czech Republic

Arabako Foru Aldundia Diputación Foral de Álava Vitoria Gasteiz ES Spain

Asociación Hontza Salvatierra Agurain Spain

Biological Station Gütersloh Bielefeld Bielefeld Germany

Brandenburg State Agency for Environment Bird Conservation Centre Buckow Germany

CERM Endangered Raptors Centre Association Rocchette di Fazio Italy

Czech Society for Ornithology Praha Czech Republic

Deltamilieu Projecten Vlissingen the Netherlands

Departament de Biologia Animal Biologia Vegetal i Ecologia Universitat Autònoma de Barcelona Bellaterra Catalonia Spain

Département Études Natagora Namur Belgium

Department of Animal Behaviour Bielefeld University Bielefeld Germany

Department of Behavioural Ecology Bielefeld University Bielefeld Germany

Department of Biology and Wildlife Diseases Faculty of Veterinary Hygiene and Ecology University of Veterinary Sciences Brno Brno Czech Republic

Department of Biology Lund University Lund Sweden

Department of Biology University of Turku Turku Finland

Department of Ornithology Aranzadi Sciences Society San Sebastián Spain

Des op Záchranná Stanice živočichů Plzeň Plzeň Czech Republic

Directora de Programas de Conservación Dirección General de Sostenibilidad de la Junta de Extremadura Mérida Spain

District of Lippe Lower Nature Conservation Authority Detmold Germany

Ecological and Forestry Applications Research Centre Bellaterra Catalonia Spain

Fertő Hanság Nemzeti Park Igazgatóság Sarród Hungary

Förderverein für Ökologie Und Monitoring von Greifvogel und Eulenarten e 5 Halle Germany

Förderverein Sächsische Vogelschutzwarte Neschwitz eV Neschwitz Germany

Gobierno de Aragon Edificio San Pedro Nolasco Zaragoza Spain

GREFA Madrid Spain

Independent Researcher Madrid Spain

Institute of Materials Chemistry TU Wien Vienna Austria

Institute of Wildlife Biology and Game Management Department of Ecosystem Management Climate and Biodiversity University of Natural Resources and Life Sciences Vienna Austria

Instituto de Investigación en Recursos Cinegéticos Ciudad Real Spain

Joint Institute for Individualisation in a Changing Environment University of Münster and Bielefeld University Bielefeld Germany

Konrad Lorenz Research Center Core Facility for Behavior and Cognition University of Vienna Grünau im Almtal Austria

LEA LandesEnergieAgentur Hessen GmbH Wiesbaden Germany

Leibniz Institute for zoo and Wildlife Research Department Wildlife Diseases Berlin Germany

LIFE EUROKITE External Assistant Březolupy Czech Republic

LIFE EUROKITE External Assistant Bützow Germany

LIFE EUROKITE External Assistant Germany

LIFE EUROKITE External Assistant Gifhorn Germany

LIFE EUROKITE External Assistant Planá nad LužnicíLužnicí Czech Republic

LIFE EUROKITE External Assistant Praha Czech Republic

LIFE EUROKITE External Assistant Uelzen Germany

LIFE EUROKITE External Assistant Weimar Germany

LPO AURA Auvergne Clermont Ferrand France

LPO AURA Loire Saint Étienne France

LPO Champagne Ardenne Ferme Des Grands Parts Outines France

LPO France Direction Territoriale Aquitaine Avenue de la Gare Saint Jean pied de port France

LPO France Fonderies Royales Rochefort CS France

LPO Occitanie Palmas d'Aveyron Aveyron France

Max Planck Institute of Animal Behavior Radolfzell am Bodensee Germany

Mitteleuropäische Gesellschaft Zur Erhaltung der Greifvögel Deutschland Fulda Germany

Natur and ëmwelt ASBL Kockelscheuer Luxembourg

Naturschutzsyndikat Sicona Luxembourg Luxembourg

Navarra Environmental Management Pamplona Spain

Ochrana Dravcov Na Slovensku Raptor Protection of Slovakia Bratislava Slovakia

ÖKOTOP Büro für Angewandte Landschaftsökologie Halle Germany

Pro Vértes Természetvédelmi Közalapítvány Hungary

Research Institute of Wildlife Ecology Department for Interdisciplinary Life Sciences Vienna Austria

Rotmilanzentrum Am Heineanum Halberstadt Germany

RSPB Scotland Edinburgh Scotland UK

School of Applied Sciences Moulsecoomb Campus University of Brighton Brighton UK

School of Geography University Park Campus University of Nottingham Nottingham UK

SEO BirdLife Madrid Spain

Swiss Ornithological Institute Sempach Switzerland

TB Raab GmbH Deutsch Wagram Austria

Turku Collegium for Science Medicine and Technology University of Turku Turku Finland

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