Wetland density is believed to be an important determinant of home range size variation in mallards (Anas platyrhynchos), but hypothesized effects of upland habitat and female size and age have not been adequately evaluated. Thus, I investigated correlates and consequences of home range size variation using radio-tracking data for 131 female mallards studied on 12 Canadian prairie parkland sites, 1995-1998. Home range size and habitat composition varied within and among study areas; overall, home range size variation was best modeled to include effects of seasonal and semi-permanent wetlands (β = -0.06 ± 0.01 SE) and wood-shrub habitat (β = -0.03 ± 0.01 SE). Contrary to predictions, I obtained no support for a positive association between home range size and female body size or a negative relationship between home range size and female age. After controlling effects of wetland density, mean home range sizes were larger on study areas with lower mallard breeding pair densities. I suspect that individual home ranges were smaller in areas of high pair density because of increased intraspecific competition for breeding space. A higher proportion of wood-shrub habitat may have contributed to smaller individual home range sizes because of greater relative availability of preferred nesting habitat. Likewise, a high proportion of wetlands in home ranges could enhance access to important resources such as food, leading to smaller home range sizes.<p> Reproductive and survival consequences were investigated using 8 variables to distinguish between three reproductive categories (females that either did not nest, nested but failed, or nested successfully) and two survival categories (dead versus alive) with discriminant function analysis. Successful females were clearly separated from non-nesting females by having smaller home ranges (95% kernel estimate) with higher percentages of wood-shrub and habitat treatment but lower percentages of seasonal and semi-permanent wetlands. Females that did not nest were further distinguished from nesting females by being younger, structurally smaller and having larger home ranges composed of higher percentages of seasonal and semi-permanent wetlands. Date of first nesting (standardized by study area) was not associated with home range composition. Survival was also unrelated to either home range composition or female attributes. Overall, breeding performance was better described by variation in landscape characteristics than by female attributes, a finding that is consistent with other recent evidence from breeding ducks.

Wetland density is believed to be an important determinant of home range size variation in mallards (Anas platyrhynchos), but hypothesized effects of upland habitat and female size and age have not been adequately evaluated. Thus, I investigated correlates and consequences of home range size variation using radio-tracking data for 131 female mallards studied on 12 Canadian prairie parkland sites, 1995-1998. Home range size and habitat composition varied within and among study areas; overall, home range size variation was best modeled to include effects of seasonal and semi-permanent wetlands (β = -0.06 ± 0.01 SE) and wood-shrub habitat (β = -0.03 ± 0.01 SE). Contrary to predictions, I obtained no support for a positive association between home range size and female body size or a negative relationship between home range size and female age. After controlling effects of wetland density, mean home range sizes were larger on study areas with lower mallard breeding pair densities. I suspect that individual home ranges were smaller in areas of high pair density because of increased intraspecific competition for breeding space. A higher proportion of wood-shrub habitat may have contributed to smaller individual home range sizes because of greater relative availability of preferred nesting habitat. Likewise, a high proportion of wetlands in home ranges could enhance access to important resources such as food, leading to smaller home range sizes.<p> Reproductive and survival consequences were investigated using 8 variables to distinguish between three reproductive categories (females that either did not nest, nested but failed, or nested successfully) and two survival categories (dead versus alive) with discriminant function analysis. Successful females were clearly separated from non-nesting females by having smaller home ranges (95% kernel estimate) with higher percentages of wood-shrub and habitat treatment but lower percentages of seasonal and semi-permanent wetlands. Females that did not nest were further distinguished from nesting females by being younger, structurally smaller and having larger home ranges composed of higher percentages of seasonal and semi-permanent wetlands. Date of first nesting (standardized by study area) was not associated with home range composition. Survival was also unrelated to either home range composition or female attributes. Overall, breeding performance was better described by variation in landscape characteristics than by female attributes, a finding that is consistent with other recent evidence from breeding ducks.

Conservation programs for breeding ducks in North America are typically designed to enhance nest success by establishing or restoring attractive perennial nesting cover or promoting favourable agricultural practices. Thus, a central objective is to attract ducks to habitats where females have higher survival and reproductive rates, primarily greater nest success. Using data collected from 1993 – 2000, I investigated hypotheses proposed to explain inconsistent patterns of habitat selection detected during nesting and brood–rearing stages in free-ranging mallards (Anas platyrhynchos) throughout the Canadian Prairie Parklands. By simultaneously considering indices of body condition and size of male and female mallards and plumage score of males, I also evaluated the role of male quality in reproductive investment and patterns of breeding success of females. In general, wild mallards mated assortatively by body condition but not body size. Yearling females nested earlier and had higher nest survival when mated to males with better plumage quality. When paired with larger-bodied males, yearling females renested more often, whereas nest and brood survival increased among older females. I characterized the habitat composition of 100 and 500 m radius buffers surrounding nest sites and related habitat features to survival of nests, broods and females. Habitat selection trade-offs were detected among perennial habitats and planted cover, such that nest survival increased in these habitats whereas duckling survival decreased. Furthermore, at large spatial scales, nest survival decreased in areas with greater amounts of cropland whereas duckling survival increased. Survival rates of females increased with greater amounts of seasonal wetlands, but nest survival decreased in such areas. Semi-permanent wetlands were associated with decreased nest survival at larger spatial scales, but associated with higher nest success at finer scales. Benefits of increasing perennial and planted cover habitats to increase nest survival could be partly offset by costs in terms of lower duckling survival, whereas opposite patterns existed in areas of abundant seasonal. The restoration of seasonal wetlands in perennial habitats could offset these trade-offs but net impacts of habitat selection and survival trade-offs on annual reproductive success must first be evaluated.

The Mississippi Alluvial Valley (MAV) is an important region for wintering mallards (Anas platyrhynchos) in North America, yet little is known about their spatiotemporal habitat use and related survival in Mississippi. I tracked 126 radio-marked female mallards to quantify survival, habitat use, and use of wildlife management areas (WMAs) with experimental hunt regimes in the south MAV of Mississippi during winters 2010-2012. Daily survival was greatest in agricultural (0.997) and moist-soil (0.999) habitats in winters 2010-2011 and 2011-2012, respectively. Overall interval survival across both winters was 0.60 (SE = 0.02). Forested (40-54%) and moist-soil wetlands (41-59%) received greatest use diurnally and nocturnally, respectively. Mallards used WMAs similarly (P > 0.22) whether they were hunted 2- or 4-days/week. My data suggest that complexes of flooded cropland, forest, and moist-soil habitats are suitable habitats for mallards in the MAV, WMAs can be hunted 4-days/week, and sanctuaries should be revised at two WMAs.

Nous avons étudié l’impact de contraintes mécaniques contrastées sur la structure des pattes de canard (Anas platyrhynchos) pour comprendre l’influence de l’environnement sur la variabilité phénotypique. Des canards ont été élevés sous quatre conditions expérimentales: 1/ marche restreinte, 2/ marche libre 3/marche augmentée 4/ marche et nage. Les vingt-huit muscles et les trois os longs de la patte de ces oiseaux ont été mesurés. Une comparaison a été faite entre les appareils locomoteurs des canards des cailles et des pies pour établir un lien entre les types de marche et la morphologie des pattes. Les résultats montrent que les muscles sont principalement affectés par une restriction de mouvement, alors que les os sont principalement touchés par une augmentation de l’exercice. Les variations de forme des os touchent principalement le genou. Cette articulation est aussi celle qui montre la plus de variabilité au cours de la locomotion des différentes espèces comparées. / We investigated the impact of contrasting mechanical constrains on duck leg structure (Anas platyrhynchos) to understand the influence of the environment on phenotypic variability. Ducks were raised under four experimental conditions: 1/ restricted walking, 2/ free walking 3/ increased walking 4/ walking and swimming. The twenty-eight muscles and three long bones of the leg of these birds were measured. A comparison was made between locomotive devices of quail, ducks and magpies to establish a link between the types of walking and the morphology of the legs. The results show that the muscles are mainly affected by a restriction of movement, while the bones are mainly affected by an increase in exercise. The variations in the shape of the bones mainly affect the knee. This joint is also the one that shows the most variability during the locomotion of the different compared species.

The influence of incubation temperature on bird neonate phenotype is widely studied. In waterfowl (Anatidae), maternal effect can be divided to two main parts: clutch formation and its incubation. Therefore, waterfowl are a good model for this type of study. The egg temperature can strongly influence embryo development and survival of the hatchlings. The goal of this work was to examine the effect of incubation temperature on hatchability, incubation length, sex ratio and phenotype of European Mallard ducklings immediately after hatching. Eggs were randomly placed in one of six incubation temperatures, which ranged from 35 to 39 řC. This range corresponds with temperature range in natural mallard nests in the Czech Republic. Eggs were then artificially incubated. Newborn hatchlings were weighted and their structural size was measured, then they were killed. Some hatchlings from incubation temperatures 35.5, 36 and 37 řC were used to examine residual yolk sac mass and basic chemical composition of the yolk-free body. Hatchability was markedly lower in both extreme temperatures (35 and 39 řC). Incubation length significantly decreased with increasing incubation temperature. I failed to prove the influence of incubation temperature on hatchling body mass, but I found temperature-dependent changes of...

Limited published data exists on the Australian duck industry, particularly in relation to the nutritional requirements of the commercial duck (Anas Platyrhynchos). A series of seven experiments was designed to determine whether current nutritional recommendations for energy, lysine, methionine, threonine and tryptophan were sufficient to optimise growth, feed efficiency, and carcass characteristics of the duck. The ability of the duck to perform diet self selection was then examined for its potential use in the Australian industry. The outcome of the diet self selection experiments showed that ducks sometimes self select diets when offered choices from four diets differing in nutrient density. A key outcome of this research was the development of a revised set of nutrient specifications designed to maximise the performance of the Australian commercially grown duck. These proposed specifications could be economically beneficial to the expanding Australian duck industry / Doctor of Philosophy (PhD)

Like life-history theory, wildlife management decisions are typically predicated on trade-offs between benefits associated with investing resources to achieve higher reproductive or survival rates versus costs or risks of achieving those goals. On the Canadian prairies, most waterfowl conservation resources are directed to policies and programs that seek to increase duck nesting success. Limited attention has focused on post-hatching life-cycle stages, yet, despite considerable recent work on duckling survival rates, many uncertainties remain concerning how abiotic and biotic factors affect duckling survival rates. The role of upland habitat characteristics may be important but has received limited attention. I evaluated hypothesized sources of variation in duckling survival for 617 mallard (Anas platyrhynchos) broods on 27 Canadian prairie-parkland sites, with emphasis on assessing effects of managed and remnant natural upland habitats. I contrasted suites of a priori and post hoc exploratory models that incorporated effects of landscape, weather, female and brood-related variables to explain variation in duckling survival rates. Survival was lower for ducklings that used areas with high proportions of semi-permanent wetlands, as well as for broods that travelled farther overland. Exploratory analyses revealed further that survival of ducklings was negatively related to the amount of managed hayland. In contrast, duckling survival was positively associated with the amount managed grassland. There was no evidence of trade-offs between benefits of managing habitat to enhance duck nesting success versus costs in terms of lower subsequent duckling survival.<p> I also addressed unresolved questions about how birds balance costs and benefits of selecting habitats by determining the survival consequences of habitat choices made during brood-rearing. In theory, fitness should be higher in preferred habitats, but this assumption is rarely tested. Fitness consequences (i.e., duckling survival) of habitat selection patterns were determined at landscape and local scales using logistic regression and information-theoretic model selection techniques. Best-approximating landscape-level models indicated that mallard females selected brood-rearing areas with a high proportion of wetland and perennial upland habitats, but duckling survival was not related to habitat selection patterns at this scale. At finer spatial scales, females selected brood-rearing areas with high proportions of wetland habitats, but, contrary to expectation, duckling survival was lower when females raised their broods in these areas. Females avoided areas with abundant perennial cover and wetlands with little vegetative cover and, consistent with prediction, duckling survival was higher when females selected areas with low perennial cover. Thus, females did not consistently select brood-rearing habitats that conferred the highest fitness benefits. Rather, the relationship between habitat selection and duckling survival depended on spatial scale and habitats considered.

Like life-history theory, wildlife management decisions are typically predicated on trade-offs between benefits associated with investing resources to achieve higher reproductive or survival rates versus costs or risks of achieving those goals. On the Canadian prairies, most waterfowl conservation resources are directed to policies and programs that seek to increase duck nesting success. Limited attention has focused on post-hatching life-cycle stages, yet, despite considerable recent work on duckling survival rates, many uncertainties remain concerning how abiotic and biotic factors affect duckling survival rates. The role of upland habitat characteristics may be important but has received limited attention. I evaluated hypothesized sources of variation in duckling survival for 617 mallard (Anas platyrhynchos) broods on 27 Canadian prairie-parkland sites, with emphasis on assessing effects of managed and remnant natural upland habitats. I contrasted suites of a priori and post hoc exploratory models that incorporated effects of landscape, weather, female and brood-related variables to explain variation in duckling survival rates. Survival was lower for ducklings that used areas with high proportions of semi-permanent wetlands, as well as for broods that travelled farther overland. Exploratory analyses revealed further that survival of ducklings was negatively related to the amount of managed hayland. In contrast, duckling survival was positively associated with the amount managed grassland. There was no evidence of trade-offs between benefits of managing habitat to enhance duck nesting success versus costs in terms of lower subsequent duckling survival.<p> I also addressed unresolved questions about how birds balance costs and benefits of selecting habitats by determining the survival consequences of habitat choices made during brood-rearing. In theory, fitness should be higher in preferred habitats, but this assumption is rarely tested. Fitness consequences (i.e., duckling survival) of habitat selection patterns were determined at landscape and local scales using logistic regression and information-theoretic model selection techniques. Best-approximating landscape-level models indicated that mallard females selected brood-rearing areas with a high proportion of wetland and perennial upland habitats, but duckling survival was not related to habitat selection patterns at this scale. At finer spatial scales, females selected brood-rearing areas with high proportions of wetland habitats, but, contrary to expectation, duckling survival was lower when females raised their broods in these areas. Females avoided areas with abundant perennial cover and wetlands with little vegetative cover and, consistent with prediction, duckling survival was higher when females selected areas with low perennial cover. Thus, females did not consistently select brood-rearing habitats that conferred the highest fitness benefits. Rather, the relationship between habitat selection and duckling survival depended on spatial scale and habitats considered.

Après avoir fait la synthèse des connaissances sur le saturnisme chez les Anatidés et rappelé l'importance de la compétitivité, notamment en terme de recherche alimentaire et de condition corporelle, pour la survie et le succès reproducteur d'un individu en milieu naturel, l'auteur décrit les effets de l'ingestion d'un faible nombre de plombs de chasse chez le Canard colvert. Il montre que la vitesse d'ingestion de l'aliment est corrélée de façon négative à la plombémie jusqu'à quatre semaines au minimum après ingestion des plombs. A ce stade, la condition corporelle, estimée par un index d'adiposité et un index musculaire, est inversement proportionnelle à plusieurs paramètres toxicologiques témoins de l'intoxication par le plomb (protoporphyrinémie, hématocrite, concentration en plomb dans les tissus). De même, il existe une corrélation entre plusieurs de ces paramètres et la perte de poids maximum relevée au cours de l'évolution de l'intoxication. On peut donc penser que l'ingestion d'un faible nombre de plombs de chasse, à l'origine d'une intoxication sublétale, voire subclinique, a un effet négatif sur l'acquisition et le stockage des réserves énergétiques chez les Anatidés. D'autre part, une régression logistique montre que la protoporphyrinémie deux semaines après l'ingestion des plombs décrit très bien la probabilité de survie des canards. Ainsi, la comparaison des corrélations entre symptômes et indicateurs toxicologiques propose que, dans les conditions de l'expérimentation, la protoporphyrinémie serait mieux adaptée que la plombémie pour dépister le saturnisme.