Robust estimation of survival and contribution of captive‐bred Mallards Anas platyrhynchos to a wild population in a large‐scale release programme |
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| Authors: | Jocelyn Champagnon Pierre Legagneux Guillaume Souchay Pablo Inchausti Vincent Bretagnolle François Bourguemestre Laura Van Ingen Matthieu Guillemain |
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| Affiliation: | 1. Centre de recherche de la Tour du Valat, Le Sambuc, Arles, France;2. Office National de la Chasse et de la Faune Sauvage – Unité Avifaune Migratrice, Le Sambuc, Arles, France;3. CEFE UMR 5175, CNRS – Université de Montpellier – Université Paul‐Valéry Montpellier – EPHE, Montpellier, France;4. Office National de la Chasse et de la Faune Sauvage – Unité Avifaune Migratrice, Beauvoir sur Niort, France;5. CEBC CNRS, UMR 7372 CNRS & Université de La Rochelle, Beauvoir sur Niort, France;6. Département de Biologie & Centre d'études Nordiques, Pavillon Vachon, Université Laval Québec, QC, Canada;7. Centro Universitario Regional del Este, Universidad de la República, Maldonado, Uruguay;8. Fédération Départementale des Chasseurs de l'Indre, Chateauroux Cedex, France;9. Réserve Naturelle de Chérine, Saint‐Michel‐en‐Brenne, France |
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| Abstract: | The survival of captive‐bred individuals from release into the wild to their first breeding season is crucial to assess the success of reintroduction or translocation programmes, and to assess their potential impact of wild populations. However, assessing the survival of captive‐bred individuals following their release is often complicated by immediate dispersal once in the wild. Here, we apply Lindberg's robust design model, a method that incorporates emigration from the study site, to obtain true estimates of survival of captive‐bred Mallards Anas platyrhynchos, a common duck species released on a large scale in Europe since the 1970s. Overall survival rate from release in July until the onset of the next breeding season in April was low (0.18 ± 0.07 se) and equivalent to half the first‐year survival of local wild Mallards. Higher overall detectability and temporary emigration during the hunting period revealed movements in response to hunting pressure. Such low survival of released Mallards during their first year may help prevent large‐scale genetic mixing with the wild population. Nevertheless, by combining our results with regional waterfowl counts, we estimated that a minimum of 34% of the Mallards in the region were of captive origin at the onset of the breeding season. Although most released birds quickly die, restocking for hunting may be of sufficient magnitude to affect the wild population through genetic homogenization or loss of local adaptation. Robust design protocols allow for the estimation of true survival estimates by controlling for permanent and temporary emigration and may require only a moderate increase in fieldwork effort. |
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| Keywords: |
Anas platyrhynchos
hand‐reared birds hunting reintroduction restocking survival |
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