Effect of predation risk, body size, and habitat characteristics on emigration decisions in mallards

Legagneux, Pierre; Inchausti, Pablo; Bourguemestre, François; Latraube, Franck; Bretagnolle, Vincent

doi:10.1093/beheco/arn133

Cited by 17 publications

(25 citation statements)

References 43 publications

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“…For the hunting season, the first month of hunting (from 15 August to 15 September) was separated from the other months because hunting pressure is higher at the opening of the season (Legagneux et al . ). Outside the hunting season, we also separated pre‐ and post‐hunting periods (August vs. March–April).…”

Section: Methodsmentioning

confidence: 97%

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Robust estimation of survival and contribution of captive‐bred Mallards Anas platyrhynchos to a wild population in a large‐scale release programme

Guillemain

Legagneux

Souchay

et al. 2016

Ibis

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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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Section: Methodsmentioning

confidence: 97%

“…), is likely to result in lower resighting rates during the hunting season (greater emigration; Legagneux et al . ). However, the low dispersal ability of captive‐bred Mallards is likely to mitigate the magnitude of such a disturbance effect and subsequent movements by the birds.…”

mentioning

confidence: 97%

Robust estimation of survival and contribution of captive‐bred Mallards Anas platyrhynchos to a wild population in a large‐scale release programme

Guillemain

Legagneux

Souchay

et al. 2016

Ibis

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“…However, all studies to date addressing survival of such birds have, to date, been carried out specifically in hunted areas. As a matter of fact, in the study by Legagneux et al (2009), at least 35% of the ringed birds were recovered by hunters, and 68% of all recoveries occurred during the first month of the hunting season. Hunting is thus obviously likely to be one of the main causes of mortality in released Mallards, but study designs have so far prevented from assessing if these birds were potentially able to survive in nature and hence potentially to interbreed with wild conspecifics.…”

Section: Introductionmentioning

confidence: 89%

“…For example, every year, several million are bred in captivity and released in Europe alone, generally as juveniles and within 2 months of the opening of the hunting season (Champagnon et al 2009). Survival of captive-reared Mallards is generally thought to be low because of high vulnerability to hunting (Dunn et al 1995;Fog 1964;Havlin 1991;Legagneux et al 2009;Schladweiler and Tester 1972). However, all studies to date addressing survival of such birds have, to date, been carried out specifically in hunted areas.…”

Section: Introductionmentioning

confidence: 99%

Low survival after release into the wild: assessing “the burden of captivity” on Mallard physiology and behaviour

Guillemain

Elmberg

et al. 2011

Eur J Wildl Res

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Captive-reared animals used in reinforcement programs are generally less likely to survive than wild conspecifics. Digestion efficiency and naive behaviour are two likely reasons for this pattern. The Mallard is a species with high adaptability to its environment and in which massive reinforcement programs are carried out. We studied physiological and behavioural factors potentially affecting body condition and survival of captive-reared Mallards after being released. Digestive system morphology and an index of body condition were compared among three groups: captive-reared birds remaining in a farm (control), captive-reared birds released into the wild as juveniles (released) and wild-born birds (wild). We also compared behaviour and diet of released vs. wild Mallards. Finally, we conducted a 1-year survival analysis of captive-reared birds after release in a hunting-free area. Gizzard weight was lower in control Mallards, but the size of other organs did not differ between controls and wild birds. The difference in gizzard weight between released and wild birds disappeared after some time in the wild. Diet analyses suggest that released Mallards show a greater preference than wild for anthropogenic food (waste grain, bait). Despite similar time-budgets, released Mallards never attained the body condition of wild birds. As a consequence, survival probability in released Mallards was low, especially when food provisioning was stopped and during harsh winter periods. We argue that the low survival of released Mallards likely has a physiological rather than a behavioural (foraging) origin. In any case, extremely few released birds live long enough to potentially enter the breeding population, even without hunting. In the context of massive releases presently carried out for hunting purposes, our study indicates a low likelihood for genetic introgression by captive-reared birds into the wild population.

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“…Tamisier & Tamisier 1981, Cox & Afton 1996, Duncan et al 1999, Guillemain et al 2002, Legagneux et al 2009a. However, other studies also suggest that, despite following this general pattern, some individuals may nonetheless move within their winter quarter and therefore switch between day roosts separated by distances of several kilometres (Guillemain et al 2002, Legagneux et al 2009b. The aim of our study was to quantify the extent to which such switches between day roosts occur, by means of resightings of nasalsaddled teal Anas crecca.…”

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confidence: 90%

Hunting bag and distance from nearest day-roost in Camargue ducks

et al. 2008

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Reserves that are closed to hunting are important to wintering wildfowl Anatidae. Reserves can also benefit local hunters, because they are often used as day-roosts by birds prior to nocturnal feeding in surrounding wetlands. In this study, we used annual hunting bags from 45 hunting estates in the Camargue, southern France, to study the relationship between hunting success and distance to the nearest duck day-roost, which are generally located in protected areas. Five dabbling duck species Anas spp. and a diving duck species (pochard Aythya ferina) were studied. The relationship between hunting bag and distance from roost was negative in all cases except mallard Anas platyrhynchos, which is subject to specific hunting management practices (i.e. raise and release). However, a significant trend was not found for wigeon A. penelope and shoveler A. clypeata. This supports the hypothesis that hunting estates closer to protected areas are more successful. However, the decrease in hunting bags with increasing distance from the nearest roost could be seen in as little as a few thousands of metres in all species. This suggests that only hunting grounds with a distance of < 2-3 kilometres from the nearest roost may actually have increased hunting accessibility for certain duck species.

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Effect of predation risk, body size, and habitat characteristics on emigration decisions in mallards

Cited by 17 publications

References 43 publications

Robust estimation of survival and contribution of captive‐bred Mallards Anas platyrhynchos to a wild population in a large‐scale release programme

Robust estimation of survival and contribution of captive‐bred Mallards Anas platyrhynchos to a wild population in a large‐scale release programme

Low survival after release into the wild: assessing “the burden of captivity” on Mallard physiology and behaviour

Hunting bag and distance from nearest day-roost in Camargue ducks

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