Breeding-Season Survival of Mallard Females in the Prairie Pothole Region of Canada

Devries, James H.; Citta, John J.; Lindberg, Mark S.; Howerter, David W.; Anderson, M.

doi:10.2307/3802713

Cited by 77 publications

(114 citation statements)

References 31 publications

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“…It is not likely that we over- Northwest of YNP boundary 3 (75%) survived and one transmitter pull-out; Dome Mountain fit our data because the selected survival models were relatively simple and generally included variables documented as important in other juvenile elk survival studies (Dekker et al 1995, Raithel 2005. Also, we found that all of the selected models were candidate models even under simulated overdispersion (ĉ ¼ 3.0, Devries et al 2003) and our methods accounted for many user-induced problems except for evaluating the selected models against independent or held-back data. We used all our data because our sample was small and little was known about the influence of physiological and pathological variables on elk calf survival in a predator-rich environment.…”

Section: Survivalmentioning

confidence: 99%

“…Because no goodness-of-fit statistic is available for known-fate models, we investigated model robustness by artificially inflatingĉ (i.e, a model term representing dispersion) from 1.0 to 3.0 (i.e., no dispersion to extreme dispersion) to simulate various levels of dispersion (Devries et al 2003) reflected in quasi-AIC c (QAIC c ) values.…”

Section: Survival Analysesmentioning

confidence: 99%

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Elk Calf Survival and Mortality Following Wolf Restoration to Yellowstone National Park

Barber‐Meyer

Mech

White

2008

Wildlife Monographs

181

301

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We conducted a 3-year study (May 2003-Apr 2006 of mortality of northern Yellowstone elk (Cervus elaphus) calves to determine the cause for the recruitment decline (i.e., 33 calves to 13 calves/100 adult F) following the restoration of wolves (Canis lupus). We captured, fit with radiotransmitters, and evaluated blood characteristics and disease antibody seroprevalence in 151 calves 6 days old (68M:83F). Concentrations (x, SE) of potential condition indicators were as follows: thyroxine (T4; 13.8 lg/dL, 0.43), serum urea nitrogen (SUN; 17.4 mg/dL, 0.57), c-glutamyltransferase (GGT; 66.4 IU/L, 4.36), gamma globulins (GG; 1.5 g/dL, 0.07), and insulin-like growth factor-1 (IGF-1; 253.6 ng/mL, 9.59). Seroprevalences were as follows: brucellosis (Brucella abortus; 3%), bovine-respiratory syncytial virus (3%), bovine-viral-diarrhea virus type 1 (25%), infectious-bovine rhinotracheitis (58%), and bovine parainfluenza-3 (32%). Serum urea nitrogen, GGT, GG, and IGF-1 varied with year; T4, SUN, and GG varied with age (P 0.01); and SUN varied by capture area (P ¼ 0.02). Annual survival was 0.22 (SE¼0.035, n¼149) and varied by calving area but not year. Neonates captured in the Stephens Creek/Mammoth area of Yellowstone National Park, USA, had annual survival rates .33 higher (0.54) than those captured in the Lamar Valley area (0.17), likely due to the higher predator density in Lamar Valley. Summer survival (20 weeks after radiotagging) was 0.29 (SE ¼ 0.05, n ¼ 116), and calving area, absolute deviation from median birth date, and GG were important predictors of summer survival. Survival during winter (Nov-Apr) was 0.90 (SE ¼ 0.05, n ¼ 42), and it did not vary by calving area or year. Sixty-nine percent (n ¼ 104) of calves died within the first year of life, 24% (n ¼ 36) survived their first year, and 7% (n ¼ 11) had unknown fates. Grizzly bears (Ursus arctos) and black bears (Ursus americanus) accounted for 58-60% (n ¼ 60-62) of deaths, and wolves accounted for 14-17% (n ¼ 15-18). Summer predation (95% of summer deaths) increased, and winter malnutrition (0% of winter deaths) decreased, compared with a similar study during 1987-1990 (72% and 58%, respectively). Physiological factors (e.g., low levels of GG) may predispose calves to predation. Also, the increase in bear numbers since wolf restoration and spatial components finer than the northern range should be considered when trying to determine the causes of the northern Yellowstone elk decline. This is the first study to document the predation impacts from reintroduced wolves on elk calf mortality in an ecosystem already containing established populations of 4 other major predators (i. para determinar las causas del descenso del reclutamiento (de 33 a 13 crías /100 hembras adultas) tras la restauración del lobo (Canis lupus). Hemos capturado, marcado con radiotransmisores y evaluado las características de la sangre y la seroprevalencia de los anticuerpos a enfermedades de 151 crías 6 días (68M:83H). Las concentraciones (x, SE) de los indicadores del estado pote...

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Section: Survivalmentioning

confidence: 99%

Section: Survival Analysesmentioning

confidence: 99%

Elk Calf Survival and Mortality Following Wolf Restoration to Yellowstone National Park

Barber‐Meyer

Mech

White

2008

Wildlife Monographs

181

301

View full text Add to dashboard Cite

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“…Calendar date (1 April = 1) was a covariate that we applied across all reproductive stages. Variation in female survival due to study site and year or covariates measured at these scales (e.g., local predator communities) has been considered elsewhere (Devries et al 2003), so for this analysis we simply accounted for such variation by considering site as a random effect in all models (Rotella et al 2004). For relationships that were not necessarily linear on the logit scale, such as nest age, eggs laid, or calendar date, we also considered quadratic effects for each variable.…”

Section: Data Summarization and Statistical Methodsmentioning

confidence: 99%

“…We tracked females with ducklings at least once daily until broods were ≥ 30-days old or total brood loss occurred (Rotella and Ratti 1992). We assumed females were dead when successive radioAvian Conservation and Ecology 7(1): 1 http://www.ace-eco.org/vol7/iss1/art1/ locations showed no movement or transmitters exhibited frequency changes due to temperature shifts (Devries et al 2003), and we walked in with handheld receivers to verify mortality status.…”

Section: Study Areas and Field Methodsmentioning

confidence: 99%

“…Most previous analyses have inferred correlations between mortality and breeding activity based on calendar date (Devries et al 2003, Brasher et al 2006. However, because of individual variation in onset of nesting along with frequent nest predation and persistent renesting , individual Mallards are widely asynchronous in their breeding activities, with some individuals already engaged in broodrearing behavior before others have initiated their first nest of the season (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Costs of Reproduction in Breeding Female Mallards: Predation Risk during Incubation Drives Annual Mortality

Arnold¹,

Roche²,

Devries³

et al. 2012

ACE

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ABSTRACT. The effort expended on reproduction may entail future costs, such as reduced survival or fecundity, and these costs can have an important influence on life-history optimization. For birds with precocial offspring, hypothesized costs of reproduction have typically emphasized nutritional and energetic investments in egg formation and incubation. We measured seasonal survival of 3856 radio-marked female Mallards (Anas platyrhynchos) from arrival on the breeding grounds through brood-rearing or cessation of breeding. There was a 2.5-fold direct increase in mortality risk associated with incubating nests in terrestrial habitats, whereas during brood-rearing when breeding females occupy aquatic habitats, mortality risk reached seasonal lows. Mortality risk also varied with calendar date and was highest during periods when large numbers of Mallards were nesting, suggesting that prey-switching behaviors by common predators may exacerbate risks to adults in all breeding stages. Although prior investments in egg laying and incubation affected mortality risk, most relationships were not consistent with the cost of reproduction hypothesis; birds with extensive prior investments in egg production or incubation typically survived better, suggesting that variation in individual quality drove both relationships. We conclude that for breeding female Mallards, the primary cost of reproduction is a fixed cost associated with placing oneself at risk to predators while incubating nests in terrestrial habitats.RÉSUMÉ. L'effort investi à la reproduction peut avoir une incidence sur les coûts futurs -comme un faible taux de survie ou de fertilité -et ces coûts peuvent grandement influencer l'optimisation du cycle biologique. Chez les oiseaux dont les jeunes sont nidifuges, les coûts hypothétiques de la reproduction sont surtout liés aux efforts nutritionnel et énergétique investis dans la formation des oeufs et à l'incubation. Dans le cadre de cette étude, nous avons mesuré le taux de survie saisonnier de 3 856 Canards colverts (Anas platyrhynchos) femelles munies d'un émetteur radio, de leur arrivée sur les aires de nidification jusqu'à ce que l'élevage des jeunes soit complété ou jusqu'à l'échec de la nidification. Le taux de mortalité était de 2,5 fois plus élevé chez les femelles qui couvaient leurs oeufs en milieu terrestre, tandis qu'il a était à son plus bas niveau saisonnier au moment de l'élevage des jeunes en milieu aquatique. Le taux de mortalité a aussi varié en fonction de la date : il était à son maximum au moment où de nombreux Canards colverts nichaient, ce qui laisse croire que le changement de proies dans la diète des prédateurs communs pourrait exacerber le risque de mortalité chez les femelles à toutes les étapes de la nidification. Même si les efforts investis dans la ponte et l'incubation ont eu un effet sur le taux de mortalité, la plupart des relations n'étaient pas conformes aux prédictions de l'hypothèse des coûts de la reproduction; les femelles qui ont grandement investi dans la production d'oeufs ...

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Ecological and anthropogenic drivers of waterfowl productivity are synchronous across species, space, and time

Weegman,

Devries,

Clark

et al. 2024

Ecological Applications

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Knowledge of interspecific and spatiotemporal variation in demography–environment relationships is key for understanding the population dynamics of sympatric species and developing multispecies conservation strategies. We used hierarchical random‐effects models to examine interspecific and spatial variation in annual productivity in six migratory ducks (i.e., American wigeon [Mareca americana], blue‐winged teal [Spatula discors], gadwall [Mareca strepera], green‐winged teal [Anas crecca], mallard [Anas platyrhynchos] and northern pintail [Anas acuta]) across six distinct ecostrata in the Prairie Pothole Region of North America. We tested whether breeding habitat conditions (seasonal pond counts, agricultural intensification, and grassland acreage) or cross‐seasonal effects (indexed by flooded rice acreage in primary wintering areas) better explained variation in the proportion of juveniles captured during late summer banding. The proportion of juveniles (i.e., productivity) was highly variable within species and ecostrata throughout 1961–2019 and generally declined through time in blue‐winged teal, gadwall, mallard, pintail, and wigeon, but there was no support for a trend in green‐winged teal. Productivity in Canadian ecostrata declined with increasing agricultural intensification and increased with increasing pond counts. We also found a strong cross‐seasonal effect, whereby more flooded rice hectares during winter resulted in higher subsequent productivity. Our results suggest highly consistent environmental and anthropogenic effects on waterfowl productivity across species and space. Our study advances our understanding of current year and cross‐seasonal effects on duck productivity across a suite of species and at finer spatial scales, which could help managers better target working‐lands conservation programs on both breeding and wintering areas. We encourage other researchers to evaluate environmental drivers of population dynamics among species in a single modeling framework for a deeper understanding of whether conservation plans should be generalized or customized given limited financial resources.

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Breeding-Season Survival of Mallard Females in the Prairie Pothole Region of Canada

Cited by 77 publications

References 31 publications

Elk Calf Survival and Mortality Following Wolf Restoration to Yellowstone National Park

Elk Calf Survival and Mortality Following Wolf Restoration to Yellowstone National Park

Costs of Reproduction in Breeding Female Mallards: Predation Risk during Incubation Drives Annual Mortality

Ecological and anthropogenic drivers of waterfowl productivity are synchronous across species, space, and time

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