Mallard Brood Survival and Wetland Habitat Conditions in Southwestern Manitoba

Rotella, Jay J.; Ratti, John T.

doi:10.2307/3808865

Cited by 119 publications

(105 citation statements)

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“…Such a change would have large negative impacts on population size. Our estimate of duckling survival rate is among the lowest ever reported for ducks nesting at northern latitudes (see Rotella and Ratti 1992;Grand and Flint 1996) and is lower than estimates for Lesser Scaup in the western boreal forest of Canada (0.61, Brook 2002) and parklands of Saskatchewan (0.38, Dawson and Clark 1996). Low duckling survival could be related to delayed nest initiation.…”

Section: Duckling Survivalcontrasting

confidence: 40%

“…Low duckling survival could be related to delayed nest initiation. In other duck species nesting in the mid-continent, later hatched ducklings have poorer survival (Rotella and Ratti 1992;Dzus and Clark 1998;Guyn and Clark 1999). One study suggests that this trend may not hold for scaup (see Dawson and Clark 1996), but these same authors found that recruitment declines with hatch date (Dawson and Clark 2000).…”

Section: Duckling Survivalmentioning

confidence: 88%

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Have Lesser Scaup, <em>Aythya affinis</em>, Reproductive Rates Declined in Parkland Manitoba?

Koons

Rotella

2003

Can Field Nat

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Long-term surveys indicate that the scaup populations have declined over the past 20 years, and that this is probably the result of decreases in Lesser Scaup (Aythya affinis) rather than Greater Scaup (Aythya marila) numbers. To identify factors possibly related to the decline, we estimated demographic parameters for a local population of Lesser Scaup at Erickson, Manitoba, that was well studied before declines occurred and compared these estimates to historic rates. On average, nests were initiated later than in the past, and recent estimates of nesting success and duckling survival were lower than historical estimates. Breeding-season survival of adult females was estimated as 72.6%, with most (83%) mortality occurring during nesting. Current estimates of demographic rates at Erickson are too low to maintain a stable local population, and suppressed reproductive rates might be the proximate cause of the local population decline.

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Section: Duckling Survivalcontrasting

confidence: 40%

Section: Duckling Survivalmentioning

confidence: 88%

Have Lesser Scaup, <em>Aythya affinis</em>, Reproductive Rates Declined in Parkland Manitoba?

Koons

Rotella

2003

Can Field Nat

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“…We stopped daily tracking of females if they were observed unpaired and flocked on at least two different days, or after two weeks had elapsed since the last known nest initiation on each study site. 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%

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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“…I examined covariates for temporal, broodspecific, wetland-specific, and landscape-level anthropogenicdevelopment variables (Table 2). I included models that allowed brood survival to vary over the season (with day 1 equal to the day the first nest hatched), and modeled season as both a linear trend and by year (Ringelman and Longcore 1982, Rotella and Ratti 1992, Guyn and Clark 1999, Traylor and Alisauskas 2006. Brood variables included brood age in days (d) and brood size at hatching (McAuley and Longcore 1988, Korschgen et al 1996b, Traylor and Alisauskas 2006.…”

Section: Discussionmentioning

confidence: 99%

“…Hens may move broods from nesting lakes to get to better brood-rearing areas (Dzubin and Gollop 1972, Ball et al 1975, Rotella and Ratti 1992, Wayland and McNicol 1994. Better brood-rearing areas might have more invertebrates for ducklings or provide more safety from duckling predators (Talent et al 1982, Rotella and Ratti 1992, Wayland and McNicol 1994, Grand and Flint 1996 than nesting areas. Important duckling predators in forested portions of Minnesota include mink, Bald Eagles (Haliaeetus leucocephalus), turtles, and fish (Roy et al 2012), yet few of the nesting and brood-rearing lakes in this study had fish.…”

Section: K W I Devmentioning

confidence: 99%

Nest and brood survival of Ring-necked Ducks in relation to anthropogenic development and wetland attributes

Roy¹

2018

ACE

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ABSTRACT. The boreal and hemiboreal forests are facing increasing anthropogenic development in areas that have traditionally been remote and inaccessible. Although these forests are recognized as important to breeding waterfowl, breeding season vital rates and the influence of anthropogenic development on these rates remain largely unexplored. I estimated nest and brood survival of Ring-necked Ducks (Aythya collaris) in the hemiboreal forest of Minnesota. I located 115 nests on 43 wetlands, radio-tagged 65 nesting hens, and monitored 32 broods. I considered the influence of distance to and density of buildings and roads, and road-surface type, as well as wetland characteristics and other variables hypothesized to influence waterfowl vital rates. The best-supported nest survival models included covariates for distance from the nest to nearest road and road-surface type. Nest survival declined with increasing distance from roads and was higher for nests near paved roads, at least when the distance was < 400 m. However, an interaction term in the topranked model suggested the effect of road type varied as a function of distance from nest. The model-averaged estimate of 35-day nest survival, based on the top two models was 0.278 (SE = 0.048). Brood survival increased with brood age and open water area, and decreased with nesting habitat area and distance from open water to nearest road. Cumulative brood survival to 30 days was 0.263 (SE = 0.035). These findings indicate that roads may influence both nest and brood survival. Furthermore, higher brood survival at wetlands with less nesting habitat area and more open water area may explain why hens move broods. Conservation managers should consider how habitat needs change throughout the breeding season to adequately address the needs of Ring-necked Ducks. Further study is needed to understand how anthropogenic development can be incorporated into conservation planning. Survie des nids et des couvées de Fuligules à collier en relation avec le développement d'origine anthropique et les caractéristiques des milieux humidesRÉSUMÉ. Les forêts boréales et hémi-boréales subissent une augmentation du développement d'origine anthropique dans des régions qui étaient autrefois éloignées et inaccessibles. Bien qu'on sache que ces forêts sont importantes pour la nidification de la sauvagine, les paramètres vitaux en saison de nidification et l'influence du développement d'origine anthropique sur ce groupe d'oiseaux demeurent grandement inexplorés. Les taux de survie de nids et de couvées de Fuligules à collier (Aythya collaris) ont été estimés dans la forêt hémi-boréale du Minnesota. Cent-quinze nids situés dans 43 milieux humides ont été localisés, 56 femelles nicheuses ont été équipées d'émetteurs radios et 32 couvées ont été suivies. L'effet de la distance et de la densité des bâtiments et des routes ont été examinés, tout comme le type de revêtement des routes, de même que les caractéristiques des milieux humides et d'autres variables pouvant influer les taux de survie de la s...

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Mallard Brood Survival and Wetland Habitat Conditions in Southwestern Manitoba

Cited by 119 publications

References 0 publications

Have Lesser Scaup, <em>Aythya affinis</em>, Reproductive Rates Declined in Parkland Manitoba?

Have Lesser Scaup, <em>Aythya affinis</em>, Reproductive Rates Declined in Parkland Manitoba?

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

Nest and brood survival of Ring-necked Ducks in relation to anthropogenic development and wetland attributes

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