Demographics of Breeding Female Mallards in Southern Ontario, Canada

Hoekman, Steven T.; Gabor, T. Shane; Maher, Ron; Murkin, Henry R.; Lindberg, Mark S.

doi:10.2193/0022-541x(2006)70[111:dobfmi]2.0.co;2

Cited by 23 publications

(42 citation statements)

References 45 publications

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“…Our estimate of overall nest success (0.16) was within the range of values reported for other regions throughout the breeding range of mallards (McLandress et al ; Stephens et al ; Hoekman et al a , b ; Davis ; Howerter et al ). As we predicted, we found landscape type influenced success, with the survival rate of nests on publicly managed lands >5 times higher than on agricultural lands (0.392 vs. 0.075).…”

Section: Discussionsupporting

confidence: 86%

“…Our estimate of breeding incidence (53%) in eastern Washington is considerably lower than values from the Prairie Parkland region of Canada (89%; Devries et al ); Ontario, Canada (96%; Hoekman et al a ); and the Great Lakes Region of the United States (84%; Coluccy et al ). Our overall estimate of breeding incidence is lower than that for first‐year females characterized as being in poor condition in the Prairie Parkland Region (60%; Devries et al ).…”

Section: Discussioncontrasting

confidence: 55%

“…Our overall survival rate of adult female mallards during the breeding season (0.895) was higher than estimates from the Prairie Pothole Region (0.65–0.87; Devries et al , Brasher et al , Arnold et al , Howerter et al ); Southern Ontario (0.65–0.84; Hoekman et al a ); Great Lakes Region (0.74; Coluccy et al ); New Brunswick, Canada (0.80; Petrie et al ); and northeast California (0.59; Mauser et al ). On the prairies, female mortality is highest during incubation when females are exposed to a range of terrestrial predators and breeding season survival is most influential on annual survival (Arnold et al ).…”

Section: Discussionmentioning

confidence: 50%

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Population dynamics of mallards breeding in eastern Washington

et al. 2016

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Variation in regional population trends for mallards breeding in the western United States indicates that additional research into factors that influence demographics could contribute to management and understanding the population demographics of mallards across North America. We estimated breeding incidence and adult female, nest, and brood survival in eastern Washington in 2006 and 2007 by monitoring female mallards with radio telemetry and tested how those parameters were influenced by study year (2006 vs. 2007), landscape type (agricultural vs. natural), and age (second year [SY] vs. after second year [ASY]). We also investigated the effects of female body condition and capture date on breeding incidence, and nest initiation date and hatch date on nest and brood survival, respectively. We included population parameters in a stage‐based demographic model and conducted a perturbation analysis to identify which vital rates were most influential on population growth rate (λ). Adult female survival was best modeled with a constant weekly survival rate (0.994, SE = 0.003). Breeding incidence differed between years and was higher for birds in better body condition. Nest survival was higher for ASY females (0.276, SE = 0.118) than SY females (0.066, SE = 0.052), and higher on publicly managed lands (0.383, SE = 0.212) than agricultural (0.114, SE = 0.058) landscapes. Brood survival was best modeled with a constant rate for the 7‐week monitoring period (0.50, SE = 0.155). The single variable having the greatest influence on λ was non‐breeding season survival, but the combination of parameters from the breeding grounds explained a greater percent of the variance in λ. Mallard population growth rate was most sensitive to changes in non‐breeding survival, nest success, brood survival, and breeding incidence. Future management decisions should focus on activities that improve these vital rates if managers want to increase the production of mallards in eastern Washington. © 2016 The Wildlife Society.

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Section: Discussionsupporting

confidence: 86%

Section: Discussioncontrasting

confidence: 55%

Section: Discussionmentioning

confidence: 50%

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Population dynamics of mallards breeding in eastern Washington

et al. 2016

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“…Estimates of vital rates help managers identify the life stages that most strongly contribute to population change (Hitchcock andGratto-Trevor 1997, Schmutz et al 1997) and are most amenable to management action (Hoekman et al 2006, Taylor et al 2012. Understanding factors associated with variation in vital rates (Schmutz andEly 1999, Schmutz et al 2001) can help assess the impacts of environmental change and anthropogenic disturbance on wildlife populations (Esler et al 2000, Votier et al 2005.…”

Section: Introductionmentioning

confidence: 99%

Factors influencing nest survival and productivity of Red-throated Loons (Gavia stellata) in Alaska

et al. 2014

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Identifying post-breeding migration and wintering distributions of migratory birds is important for understanding factors that may drive population dynamics. Red-throated Loons (Gavia stellata) are widely distributed across Alaska and currently have varying population trends, including some populations with recent periods of decline. To investigate population differentiation and the location of migration pathways and wintering areas, which may inform population trend patterns, we used satellite transmitters (n = 32) to describe migration patterns of four geographically separate breeding populations of Red-throated Loons in Alaska. On average (± SD) Red-throated Loons underwent long (6,288 ± 1,825 km) fall and spring migrations predominantly along coastlines. The most northern population (Arctic Coastal Plain) migrated westward to East Asia and traveled approximately 2,000 km farther to wintering sites than the three more southerly populations (Seward Peninsula, Yukon-Kusko-kwim Delta, and Copper River Delta) which migrated south along the Pacific coast of North America. These migration paths are consistent with the hypothesis that Red-throated Loons from the Arctic Coastal Plain are exposed to contaminants in East Asia. The three more southerly breeding populations demonstrated a chain migration pattern in which the more northerly breeding populations generally wintered in more northerly latitudes. Collectively, the migration paths observed in this study demonstrate that some geographically distinct breeding populations overlap in wintering distribution while others use highly different wintering areas. Red-throated Loon population trends in Alaska may therefore be driven by a wide range of effects throughout the annual cycle.

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“…The losses noted in North America (Herkert 1994, 1997, McCracken 2005, Faaborg et al 2010) have mirrored or even exceeded farmland bird declines in the intensively farmed European landscapes (Bradbury et al 2000, Chamberlain et al 2000. For example, the Bobolink (Dolichonyx oryzivorus) declined 80% between 1968-2006(Downes et al 2011; the same time period saw a 78% decline in Grasshopper Sparrows (Ammodramus savannarum), with a 25% loss among Savannah Sparrow (Passerculus sandwichensis) populations (Downes et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Estimated Mortality of Selected Migratory Bird Species from Mowing and Other Mechanical Operations in Canadian Agriculture

Tews¹,

Bert²,

Mineau³

2013

ACE

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ABSTRACT. Mechanical operations such as mowing, tilling, seeding, and harvesting are well-known sources of direct avian mortality in agricultural fields. However, there are currently no mortality rate estimates available for any species group or larger jurisdiction. Even reviews of sources of mortality in birds have failed to address mechanical disturbance in farm fields. To overcome this information gap we provide estimates of total mortality rates by mechanical operations for five selected species across Canada. In our step-by-step modeling approach we (i) quantified the amount of various types of agricultural land in each Bird Conservation Region (BCR) in Canada, (ii) estimated population densities by region and agricultural habitat type for each selected species, (iii) estimated the average timing of mechanical agricultural activities, egg laying, and fledging, (iv) and used these values and additional demographical parameters to derive estimates of total mortality by species within each BCR. Based on our calculations the total annual estimated incidental take of young ranged from ~138,000 for Horned Lark (Eremophila alpestris) to as much as ~941,000 for Savannah Sparrow (Passerculus sandwichensis). Net losses to the fall flight of birds, i.e., those birds that would have fledged successfully in the absence of mechanical disturbance, were, for example ~321,000 for Bobolink (Dolichonyx oryzivorus) and ~483,000 for Savannah Sparrow. Although our estimates are subject to an unknown degree of uncertainty, this assessment is a very important first step because it provides a broad estimate of incidental take for a set of species that may be particularly vulnerable to mechanical operations and a starting point for future refinements of model parameters if and when they become available.RÉSUMÉ. Les opérations mécanisées telles que le fauchage, le labourage, l'ensemencement et la récolte sont des sources bien connues de mortalité aviaire directe dans les champs agricoles. Toutefois, il n'existe actuellement aucune estimation du taux de mortalité pour tout groupe d'oiseaux ou grande région. Même les revues de littérature visant à dresser les sources de mortalité d'oiseaux n'ont pas examiné le dérangement attribué aux opérations mécanisées dans les champs agricoles. Pour pallier ce manque d'information, nous présentons des estimations du taux de mortalité totale par les opérations mécanisées chez cinq espèces dans l'ensemble du Canada. Notre approche de modélisation par étape nous a permis de : 1) quantifier la superficie de divers types de milieux agricoles dans chaque région de conservation des oiseaux (RCO) au Canada; 2) estimer les densités de population par RCO et type de milieux agricoles pour chacune des cinq espèces; 3) estimer la période moyenne des activités agricoles mécanisées, de la ponte et de l'envol de jeunes; et 4) utiliser ces valeurs et d'autres paramètres démographiques pour calculer des estimations de la mortalité totale par espèce dans chaque RCO. Selon nos calculs, la prise accessoire annuelle de...

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Demographics of Breeding Female Mallards in Southern Ontario, Canada

Cited by 23 publications

References 45 publications

Population dynamics of mallards breeding in eastern Washington

Population dynamics of mallards breeding in eastern Washington

Factors influencing nest survival and productivity of Red-throated Loons (Gavia stellata) in Alaska

Estimated Mortality of Selected Migratory Bird Species from Mowing and Other Mechanical Operations in Canadian Agriculture

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