Breeding Propensity of Female Harlequin Ducks

Bond, Jeanine C.; Esler, Daniel; Williams, Tony

doi:10.2193/2007-241

Cited by 6 publications

(4 citation statements)

References 34 publications

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“…Concerns regarding the consequence of imperfect detection for estimating apparent nest survival have been discussed since the 1960s (Mayfield , , Klett and Johnson , Pollock and Cornelius , Dinsmore et al ). However, bias associated with apparent nesting propensities have rarely been acknowledged (McPherson et al , Reed et al , Bond et al ) despite the fact that similar biases affect apparent estimates of nesting propensity. Our approach to estimate nesting propensity reduced bias associated with heterogeneity in observer effort (i.e.…”

Section: Discussionmentioning

confidence: 99%

Variable drivers of primary versus secondary nesting; density‐dependence and drought effects on greater sage‐grouse

Blomberg

Gibson

Atamian

et al. 2017

Journal of Avian Biology

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Organisms seek to maximize fitness by balancing reproductive allocations against mortality risk, given selection pressures inherent to the environment. However, environmental conditions are often dynamic and unpredictable, which complicates the ability to achieve such a balance, and may require reproductive adjustments depending on prevailing conditions. We evaluated the effects of density‐dependent, density‐independent (drought), and individual (age, body condition) factors on nesting decisions of female greater sage‐grouse in the American Great Basin. We obtained relocations and recorded reproductive histories from 287 radio‐marked females over a period of 10 yr, and applied these data to a multi‐state model that estimated probabilities of initiating a first nest (primary nesting rate) or a second nest, given loss of a first (secondary nesting rate). This approach allowed us to evaluate the relative association between nesting rates and covariates while accounting for imperfect detection of nests. Sage‐grouse primary and secondary nesting were influenced differently by density dependence and drought. Primary nesting was high and relatively constant among years despite variable drought conditions, but was negatively associated with population size (density dependence). Secondary nesting was lower and more variable compared to primary nesting, was similarly influenced by density‐dependence, and was also sensitive to drought conditions. Females known to initiate second nests were in better body condition than females that only initiated first nests, and females of intermediate age had higher primary nesting rates, whereas secondary nesting was unaffected by age. Our results suggest that females were more flexible and responded more readily to changing conditions when allocating resources to second nests. These results are consistent with patterns that have been demonstrated for female allocation to clutch size in this system, and suggest that when conditions are poor second nests reflect a tipping point where reproductive costs (increased mortality) outweigh benefits (offspring reproductive value).

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Section: Discussionmentioning

confidence: 99%

Variable drivers of primary versus secondary nesting; density‐dependence and drought effects on greater sage‐grouse

Blomberg

Gibson

Atamian

et al. 2017

Journal of Avian Biology

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“…In conjunction witb radiotelemetry and behavioral studies, yolk precursor analysis can be used to more accurately discern where in the breeding cycle failed reproduction occurs (i.e., breeding propensity, failed nesting, or clutch loss due to prédation or environmental conditions; e.g., Peery et al 2004;Bond et al 2008). Furthermore, yolk precursor analysis likely has important utility in studies of contaminant effects on reproduction in waterfowl.…”

Section: Discussionmentioning

confidence: 99%

Plasma Yolk Precursor Dynamics during Egg Production by Female Greater Scaup (Aythya marila): Characterization and Indices of Reproductive State

Gorman

Esler²,

Walzem³

et al. 2009

Physiological and Biochemical Zoology

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We characterized dynamics of the plasma yolk precursors vitellogenin (VTG), very-low-density lipoprotein (total VLDL-TG), and VLDL particle size distribution during egg production by female greater scaup (order: Anseriformes, Aythya marila). We also evaluated VTG and total VLDL-TG as physiological indices of reproductive state. Mean (+/-1 SE) plasma concentrations of VTG and total VLDL-TG for females with nondeveloped ovaries were 0.58 +/- 0.05 microg Zn mL(-1) and 3.75 +/- 0.29 mmol TG L(-1), respectively. Yolk precursor concentrations increased rapidly to maximum levels in association with small increases in ovary mass during rapid follicle growth. Mean concentrations of VTG and total VLDL-TG for females with a full ovarian follicle hierarchy were 3.38 +/- 0.40 microg Zn mL(-1) and 7.31 +/- 2.56 mmol TG L(-1), respectively. Concentrations of VTG and total VLDL remained elevated throughout the laying cycle and decreased markedly by 3 d into incubation. Individual reproductive state (non-egg producing vs. egg producing) was more accurately identified by plasma profiles of VTG (90%) than by those of total VLDL-TG (74%). Greater scaup VLDL particle sizes during egg production were within the range for predicted yolk-targeted VLDL size (25-44 nm). We conclude that plasma profiles of VTG and total VLDL-TG can be used as nonlethal, physiological indices of reproductive state in greater scaup and should be of great utility to a variety of evolutionary, ecological, and applied conservation studies of reproduction in waterfowl.

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“…Duck production and breeding are important at present (Bond et al, 2008;Lin et al, 2014). Corn is the commonest grain feedstuff and is used widely in duck production.…”

Section: Introductionmentioning

confidence: 99%

Correlation between chemical composition, EHGE and TME of corn for ducks

Chen¹,

Wang²,

Du³

et al. 2021

SA J. An. Sci.

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Correlations between chemical composition, enzymatic hydrolysate gross energy (EHGE), and true metabolizable energy (TME) of corn for ducks were investigated. Twenty-two corn samples were collected from various regions in 11 provinces of China. The crude protein (CP), ether extract (EE), neutral detergent fibre (NDF), Ash, gross energy (GE), dry matter (DM), amylopectin (AP), amylose (AM), total starch (TS), and AP/AM were determined for each sample. Five of the samples of corn were chosen at the mean, mean ± 1 standard deviation (SD), and mean ± 2 SD based on AP/AM. The EHGE of these samples was analysed using the pepsin-artificial small intestinal fluid enzymatic method. These five samples were also force-fed to male Cherry Valley ducks to assay their TME. Finally, correlation analyses were performed, and regression equations were established. Ash content, GE, and TS were highly related to EHGE. Univariate prediction equations were EHGE = 11.8566Ash-0.0421 (P <0.05), EHGE = 0.1535GE1.5642 (P <0.05), and EHGE = 0.1020TS1.1561 (P <0.05). The total starch, AP/AM, and ash of the chemical compositions were highly related to TME. The corresponding univariate regression equations were TME = 21.9355TS-0.0910 (P <0.05), TME = 15.6590AP/AM-0.0559 (P <0.05), and TME = 15.0778Ash0.0442 (P <0.05). The mean EHGE was equivalent to 78.5% of TME, but their correlation coefficient was low. In conclusion, chemical composition was predictive of EHGE and TME of corn samples for ducks, but the correlation of EHGE and TME was low Keywords: Cherry Valley duck, amylopectin, amylose, true metabolizable energy

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Breeding Propensity of Female Harlequin Ducks

Cited by 6 publications

References 34 publications

Variable drivers of primary versus secondary nesting; density‐dependence and drought effects on greater sage‐grouse

Variable drivers of primary versus secondary nesting; density‐dependence and drought effects on greater sage‐grouse

Plasma Yolk Precursor Dynamics during Egg Production by Female Greater Scaup (Aythya marila): Characterization and Indices of Reproductive State

Correlation between chemical composition, EHGE and TME of corn for ducks

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