ORIGINAL RESEARCH article
Front. Vet. Sci.
Sec. Animal Behavior and Welfare
This article is part of the Research TopicAdvancing Animal Welfare Assessment: From Biomarkers to Smart Monitoring TechnologiesView all 10 articles
Fecal Glucocorticoid Metabolites as Stress Biomarkers in Common Buzzards (Buteo buteo) Across Rehabilitation Phases: Implications for Raptor Welfare
Provisionally accepted
Lara-Luisa Grundei1*
Tanja E. Wolf2,3Florian Brandes4Karolin Schütte4
Fritjof Freise5
Ursula Siebert, Prof. Prof. H. C. Doc6
Chadi Touma2
Michael Pees1- 1Department of Small Mammal, Reptile and Avian Medicine and Surgery, Tierarztliche Hochschule Hannover, Hanover, Germany
- 2Department of Behavioral Biology, Universitat Osnabruck, Osnabrück, Germany
- 3Mammal Research Institute, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
- 4Wildlife Rescue and Conservation Center, Sachsenhagen, Germany
- 5Stiftung Tierarztliche Hochschule Hannover Institut fur Biometrie Epidemiologie und Informationsverarbeitung, Hanover, Germany
- 6Stiftung Tierarztliche Hochschule Hannover Institut fur Terrestrische und Aquatische Wildtierforschung, Hanover, Germany
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Taking wildlife into human care is a balancing act between benefits and harms, as handling and captivity can cause chronic stress that can lead to permanent physiological changes. Therefore, it is necessary to investigate stress levels during the rehabilitation of wild animals such as raptors. Fecal samples from 15 Common Buzzards (Buteo buteo) were taken to determine fecal glucocorticoid metabolite concentrations as a biomarker for stress across the rehabilitation phases. Significantly higher concentrations of fecal glucocorticoid metabolites were found during housing phase 1, when the birds were housed in small cages and handled at least once a day for medical treatment, compared to housing phase 2, when they were housed in larger and more undisturbed aviaries. The day of rehabilitation had no significant impact on fecal glucocorticoid metabolite concentrations alone or in interaction with the housing phases. The cause of admission (acute or chronic) and the eventual outcome for the birds (release or euthanasia) also had no statistically significant effect. The results suggest that handling and restraint could be main stressors during rehabilitation and should be critically evaluated throughout the rehabilitation process. Recommendations were derived from our findings to improve the welfare of birds of prey in wildlife rehabilitation.
Keywords: Animal Welfare, Behavior, Bird of prey, FGcM, hormone, Rehabilitation, Stress biomarker, wildlife
Received: 19 Dec 2025; Accepted: 10 Feb 2026.
Copyright: © 2026 Grundei, Wolf, Brandes, Schütte, Freise, Siebert, Prof. Prof. H. C. Doc, Touma and Pees. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lara-Luisa Grundei
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