Duck Harvest Research Articles

Spatiotemporal dynamics of duck harvest distributions in the Central and Mississippi flyways, 1960–2019

AbstractGeographical distributions of waterfowl exhibit annual variation in response to spatiotemporal variation in weather conditions, habitat availability, and other factors. Continuing changes in climate and land use could lead to persistent shifts of waterfowl distributions, potentially causing a mismatch with habitat conservation planning, wetland restoration efforts, and harvest management decisions informed by historical distributions. We used band recoveries and harvest records (i.e., hunter‐harvested wings) from the United States Fish and Wildlife Service Waterfowl Parts Collection Survey as indices of duck distribution in autumn and winter, and quantified intra‐annual, interannual, and interspecific variation in their geographic distributions across 6 decades (1960–2019) for 15 duck species in the Central and Mississippi flyways in North America. Specifically, we tested for annual and decadal shifts in mean latitude and longitude of recoveries for each month (Oct–Jan) by species and taxonomic guild (i.e., dabbling, diving ducks). Overall, species varied in the extent, timing, and sometimes direction, of distributional change in recoveries. From 1960–2019, mean recovery locations for dabbling ducks shifted south 105–296 km in October and 27 km in November (wings only), whereas mean latitudes shifted north 144–234 km in December and 186–301 km in January. Mean recovery locations for diving ducks shifted north 162 km in October (wings only), 84–173 km in December, and 66–120 km in January, but shifted 99–512 km south in November. Shifts in longitude were less consistent between guilds and data types. Finally, distributional change rarely accelerated during recent decades, except for southward shifts of band recoveries of diving ducks in November and northward shifts of band and wing recoveries of dabbling ducks in January. Although anecdotal accounts of large‐scale northward shifts in duck distributions are prolific in the land management and hunting communities, our data demonstrate more subtle shifts that vary considerably by species and month. Observed changes in recovery distributions could necessitate changes in timing of habitat management practices throughout the Central and Mississippi flyways and may result in fewer hunting and recreational opportunities for some species in southern states. Quantifying patterns of historical change is a necessary first step to understanding temporal and interspecific variation in waterfowl distributions, which will help with landscape‐scale conservation and management efforts in the future and enable effective communication to core constituencies regarding ongoing changes and their implications for recreational engagement.

Bayesian modelling reveals differences in long-term trends in the harvest of native and introduced species by recreational hunters in Australia

Context Little is known about wildlife harvesting by licensed recreational hunters in Australia, where both native and introduced species are hunted. It is important to understand harvest trends to assess sustainability for native species and implications for population control of introduced species. Aim The aim of this study was to analyse trends in hunter participation, activity and efficiency, and wildlife harvest, including effects of climate, in Victoria, Australia, for three game species groups: introduced deer, native waterfowl (ducks) and one native grassland species, stubble quail (Coturnix pectoralis). Methods Telephone surveys of a random sample of licenced Victorian hunters were performed annually from 2009 to 2019. Hunters were asked to quantify their hunting effort and the number of animals harvested. The respondents’ answers were analysed to estimate measures of hunter success, activity and efficiency. Bayesian modelling was applied to these data, accounting for changes over time, differences between survey periods for all licence types, and random effects for over-dispersion. The effect of climate on game bird hunter activity and harvest was estimated, as measured by the El Niño-Southern Oscillation (ENSO). Results Over 11 years, annual deer harvest (all species) increased exponentially, at a mean annual rate of 17% (95% credible interval: 14–21%), and the number of deer hunters increased at 8% (5–11%). In contrast, for ducks and stubble quail, hunter numbers remained relatively unchanged, with no evidence of consistent change to total harvests over time, unrelated to changes in environmental conditions or regulations. The annual duck harvest was influenced by ENSO and hunting regulations. The annual stubble quail harvest exhibited ‘boom-and-bust’ dynamics, with an exceptionally large harvest immediately after a La Niña season. Conclusions Long-term monitoring of harvest trends in south-eastern Australia revealed stark differences between introduced deer and native birds: harvest of deer increased rapidly whereas equivalent rates for game birds were either stable or declining. Seasonal effects had a strong influence on game bird harvest. Environmental and regulatory conditions were influential for harvest outcomes for ducks and stubble quail. Implications This study filled a key knowledge gap around managing harvesting of game species, but increased scrutiny is warranted in this field.

Genomic Evidence for Sequestration of Influenza A Virus Lineages in Sea Duck Host Species

Wild birds are considered the natural reservoir of influenza A viruses (IAVs) making them critical for IAV surveillance efforts. While sea ducks have played a role in novel IAV emergence events that threatened food security and public health, very few surveillance samples have been collected from sea duck hosts. From 2014–2018, we conducted surveillance focused in the Mississippi flyway, USA at locations where sea duck harvest has been relatively successful compared to our other sampling locations. Our surveillance yielded 1662 samples from sea ducks, from which we recovered 77 IAV isolates. Our analyses identified persistence of sea duck specific IAV lineages across multiple years. We also recovered sea duck origin IAVs containing an H4 gene highly divergent from the majority of North American H4-HA with clade node age of over 65 years. Identification of IAVs with long branch lengths is indicative of substantial genomic change consistent with persistence without detection by surveillance efforts. Sea ducks play a role in the movement and long-term persistence of IAVs and are likely harboring more undetected IAV diversity. Sea ducks should be a point of emphasis for future North American wild bird IAV surveillance efforts.

Associations between duck harvest, hunting wing ratios and measures of reproductive output in Northern Europe

Ducks are important game species, hunted in several countries throughout their annual cycle. We investigated whether the size of the annual duck harvest in Finland and Denmark reflected annual reproductive output in three common quarry duck species. Finland represents an important breeding area and Denmark important staging/wintering grounds for common teal (Anas crecca), Eurasian wigeon (Mareca penelope) and common goldeneye (Bucephala clangula). We assessed whether (i) annual duck harvest in these two countries correlated with variation in Finnish reproductive output or adult population size during 1990–2016 and (ii) variation in reproductive output of Finnish ducks was reflected in the juvenile ratios of birds harvested in Finland (2005–2007, 2014–2016) or Denmark (1990–2016). We hypothesised that variation in Finnish reproductive output would positively affect the size and juvenile ratio of the harvest, and that this effect would be stronger closer to the breeding grounds. Our data showed that the annual harvest of goldeneye in Finland was positively correlated with reproductive output, a desirable basis for applying sustainable management to this species. Teal and wigeon have much longer, more complex flyways, and their harvest did not mirror the annual production of young, although the wigeon harvest in Denmark increased with increasing juvenile ratio there. For these populations, we need to better define population units if we are to be able to assess harvest sustainability. We urgently need to monitor duck breeding success and harvest at larger spatial scales to support a comprehensive analysis of how well the harvest reflects reproductive output.

Building the foundation for international conservation planning for breeding ducks across the U.S. and Canadian border.

We used publically available data on duck breeding distribution and recently compiled geospatial data on upland habitat and environmental conditions to develop a spatially explicit model of breeding duck populations across the entire Prairie Pothole Region (PPR). Our spatial population models were able to identify key areas for duck conservation across the PPR and predict between 62.1 – 79.1% (68.4% avg.) of the variation in duck counts by year from 2002 – 2010. The median difference in observed vs. predicted duck counts at a transect segment level was 4.6 ducks. Our models are the first seamless spatially explicit models of waterfowl abundance across the entire PPR and represent an initial step toward joint conservation planning between Prairie Pothole and Prairie Habitat Joint Ventures. Our work demonstrates that when spatial and temporal variation for highly mobile birds is incorporated into conservation planning it will likely increase the habitat area required to support defined population goals. A major goal of the current North American Waterfowl Management Plan and subsequent action plan is the linking of harvest and habitat management. We contend incorporation of spatial aspects will increase the likelihood of coherent joint harvest and habitat management decisions. Our results show at a minimum, it is possible to produce spatially explicit waterfowl abundance models that when summed across survey strata will produce similar strata level population estimates as the design-based Waterfowl Breeding Pair and Habitat Survey (r2 = 0.977). This is important because these design-based population estimates are currently used to set duck harvest regulations and to set duck population and habitat goals for the North American Waterfowl Management Plan. We hope this effort generates discussion on the important linkages between spatial and temporal variation in population size, and distribution relative to habitat quantity and quality when linking habitat and population goals across this important region.

The Effects of Harvest Regulations on Behaviors of Duck Hunters

Uncertainty exists as to how duck harvest regulations influence waterfowl hunter behavior. We used the U.S. Fish and Wildlife Service’s Parts Collection Survey to examine how harvest regulations affected behaviors of Central Flyway duck hunters. We stratified hunters into ranked groups based on seasonal harvest and identified three periods (1975–1984, 1988–1993, 2002–2011) that represented different harvest regulations (moderate, restrictive, and liberal, respectively; season length and daily bag limits smallest in restrictive seasons and largest in liberal seasons). We examined variability of seven measures of duck hunter behaviors across the periods: days harvesting ducks, daily harvest, hunter mobility, mallard (Anas platyrhynchos) selectivity, gender selectivity, daily female mallard harvest, and timing of harvest. Hunters reported harvesting ducks on more days, at a higher efficiency, and in slightly more counties during liberal seasons relative to restrictive and moderate seasons. We provide evidence to suggest that future regulation change will affect hunter behaviors.

Effect of Weekly Hunting Frequency on Rate of Ducks Harvested

Abstract Waterfowl hunting is important culturally and economically in North America. Few studies have evaluated the relationship between weekly hunting frequency and rate of ducks harvested. We evaluated the effect of hunting 2 or 4 d/wk on rate of ducks harvested on three Mississippi Wildlife Management Areas, USA, during three waterfowl hunting seasons, December–January 2008–2011. Harvest of all ducks combined, mallard Anas platyrhynchos, northern shoveler Anas clypeata, or green-winged teal Anas crecca per hunter day did not differ between areas hunted 2 or 4 d/wk, but increased with hours spent afield. We suggest Wildlife Management Areas may be hunted 4 d/wk without reducing duck harvest per hunter day. We recommend continued evaluations of weekly hunting frequency on rate of ducks harvested to sustain science-guided management of waterfowl hunting on Mississippi public lands and elsewhere.

THE EFFECT OF CLIMATE CHANGE ON WETLANDS AND WATERFOWL IN WESTERN CANADA: INCORPORATING CROPPING DECISIONS INTO A BIOECONOMIC MODEL

Abstract We extend an earlier bioeconomic model of optimal duck harvest and wetland retention in the Prairie Pothole Region of Western Canada to include cropping decisions. Instead of a single state equation, the model has two state equations representing the population dynamics of ducks and the amount of wetlands. We use the model to estimate the impact of climate change on wetlands and waterfowl, including direct climate effects as well as land use change due to biofuel policies aimed at mitigating climate change. The model predicts that climate change will reduce wetlands by 37–56% from historic levels. Land use change due to biofuel policies is expected to reduce wetlands by between 35% and 45% from historic levels, whereas direct climate effects will range from a reduction of 2–11%, depending on the future climate scenario. This result indicates that models that neglect the effect of land use changes underestimate the effect of climate change on wetlands. Further, wetlands loss is geographically heterogeneous, with losses being the largest in Saskatchewan.

Spinning‐wing decoy use and reported duck harvest in Illinois: Implications for adaptive harvest management

AbstractUse of battery‐powered spinning‐wing decoys (SWDs) by duck hunters has generated questions as to the effect these decoys may have on duck harvests. I used data from the annual Illinois Waterfowl Hunter Survey for duck hunting seasons 1999 through 2003 to compare mallard (Anas platyrhynchos) and total duck harvest, reported days afield, and duck crippling rates between hunters using and not using SWDs. For the each of the 5 years reported, mean mallard harvest was greater among hunters using SWDs than among hunters not using the decoys and effect size was substantial (1999: F = 355.01, P < 0.001; 2000: F = 567.92, P < 0.001; 2001: F = 333.25, P < 0.001; 2002: F = 321.58, P < 0.001; 2003: F = 299.00, P < 0.001). Mean reported total ducks harvested was greater for decoy users than non‐users, and I found effect sizes to be substantial for all years (1999: F = 301.80, P < 0.001; 2000: F = 607.76, P < 0.001; 2001: F = 369.49, P < 0.001; 2002: F = 321.59, P < 0.001; 2003: F = 335.82, P < 0.001). Decoy users reported hunting more days than non‐users (1999: F = 71.00, P < 0.001; 2000: F = 716.50, P < 0.001; 2001: F = 486.75, P < 0.001; 2002: F = 410.72, P < 0.001; 2003: F = 466.09, P < 0.001). I observed substantial effect size for days hunted by decoy use for each year except for 1999–2000, for which effect size was typical. Hunters using SWDs reported greater crippled ducks than for hunters not using the decoys, with typical effect sizes observed for each year I examined (1999: F = 168.42, P < 0.001; 2000: F = 361.34, P < 0.001; 2001: F = 163.05, P < 0.001; 2002: F = 153.29, P < 0.001; 2003: F = 169.18, P < 0.001). I did not observe significant relationships between years of hunting experience and decoy use (R2 range = 0.051–0.071). My findings support claims that SWDs lead to increased duck harvests. Recent actions by some state wildlife management agencies have resulted in a mixed approach toward regulating use of SWDs, ranging from prohibiting their use to removing all restrictions. This study seeks to provide managers with greater understanding of potential impacts of SWD use on waterfowl harvests. © 2011 The Wildlife Society.

Bioeconomic Modeling of Wetlands and Waterfowl in Western Canada: Accounting for Amenity Values

This study reexamines and updates an original bioeconomic model of optimal duck harvest and wetland retention by Hammack and Brown (1974, Waterfowl and Wetlands: Toward Bioeconomic Analysis. Washington, DC: Resources for the Future). It then extends the model to include the nonmarket (in situ) value of waterfowl and the ecosystem service and other amenity values of wetlands in addition to the value of ducks to hunters. The focus is the prairie pothole region of Western Canada. Results indicate that wetlands and duck harvests need to be increased relative to historical levels, confirming Hammack and Brown's original conclusions. Including amenity values leads to a significant increase in the quantity of wetlands and hunters’ harvests of ducks relative to models that focus only on hunting values. Dans le présent article, nous avons revu et actualisé le modèle bioéconomique original de Hammack et Brown (1974) sur le prélèvement optimal de canards et la conservation des zones humides. Nous avons ensuite étendu le modèle afin d'inclure la valeur non marchande (in situ) de la sauvagine et des services écosystémiques, la valeur d'agrément des zones humides et la valeur des canards pour les chasseurs. Nous nous sommes concentrés sur la Région des cuvettes des Prairies dans l'Ouest canadien. Nos résultats autorisent à penser qu'il est nécessaire d'augmenter les zones humides et les prélèvements de canards par rapport aux niveaux historiques, ce qui confirme les conclusions formulées dans l'étude de Hammack et Brown. Le fait d'inclure la valeur d'agrément entraîne une augmentation significative du nombre de zones humides et de prélèvements de canards par les chasseurs comparativement aux modèles qui se concentrent uniquement sur la valeur pour la chasse.

Predicting Wood Duck Harvest Rates in Eastern North America

Abstract: We developed a method for predicting wood duck (Aix sponsa) harvest rates in eastern North America using waterfowl banding and recovery data, annual indices of hunter numbers, and harvest survey data from the United States and Canada. We predicted that under the current season length (60 days), if hunter numbers remain unchanged, increasing the wood duck bag limit from 2 to 3 would increase harvest of adult male wood ducks in the Atlantic and Mississippi flyways by 12.3%, causing an increase in harvest rate of 7.1% from 0.087 to 0.093. The Flyway Councils and the United States Fish and Wildlife Service can consider this information to predict the impacts of regulatory changes.

Predicting Wood Duck Harvest Rates in Eastern North America

Predicting Wood Duck Harvest Rates in Eastern North America

Modeling Movement and Fidelity of American Black Ducks

Spatial relationships among stocks of breeding waterfowl can be an important component of harvest management. Prediction and optimal harvest management under adaptive harvest management (AHM) requires information on the spatial relationships among breeding populations (fidelity and inter-year exchange), as well as rates of movements from breeding to harvest regions. We used band-recovery data to develop a model to estimate probabilities of movement for American black ducks (Anas rubripes) among 3 Canadian breeding strata and 6 harvest regions (3 in Canada, and 3 in the United States) over the period 1965–1998. Model selection criteria suggested that models containing area-, year-, and age-specific recovery rates with area- and sex-specific movement rates were the best for modeling movement. Movement by males to southern harvest areas was variable depending on the originating area. Males from the western breeding area predominantly moved to the Mississippi Flyway or southern Atlantic Flyway (Ψij = 0.353, SE = 0.0187 and Ψij = 0.473, SE = 0.037, respectively), whereas males that originated in the eastern and central breeding strata moved to the northern Atlantic flyway (Ψij = 0.842, SE = 0.010 and Ψij = 0.578, SE = 0.0222, respectively). We used combined recoveries and recaptures in Program MARK to estimate fidelity to the 3 Canadian breeding strata. Information criteria identified a model containing sex- and age-specific fidelity for black ducks. Estimates of fidelity were 0.9695 (SE = 0.0249) and 0.9554 (SE = 0.0434) for adult males and females, respectively. Estimates of fidelity for juveniles were slightly lower at 0.9210 (SE = 0.0931) and 0.8870 (SE = 0.0475) for males and females, respectively. These models have application to the development of spatially stratified black duck harvest management models for use in AHM.

Hunting Activity Record-Cards and the Accuracy of Survey Estimates

Sending hunting activity record-cards prior to a hunting season has been recommended as a methodology for reducing digit preference (heaps on numbers ending in 0 and 5) and improving the accuracy of participation and harvest estimates derived from survey responses. This article examines the extent to which record-cards influence the number of 0–5 responses and contributes to changes in mean days of duck hunting and harvest. Data were obtained from the 1999–2000 Illinois Waterfowl Hunter Survey. Approximately half of the respondents (n = 1,717, response rate = 72%) were mailed the preseason record-card; the other half of the sample (n = 1,430, response rate = 61%) were not mailed the record-card. Record-card recipients reported less 0–5 heaping, but excessive 0–5 heaping explained only 20% or less of the change in means. Changes in mean estimates were primarily the result of more reporting of low days of participation and harvest by record-card recipients. Sending out record-cards prompted more individuals in a sample with low days of participation and low harvest to become respondents. Given that record-cards are relatively inexpensive, the authors encourage state fish and wildlife agencies to adopt this methodology.

Waterfowl Use in Relation to Size and Cost of Potholes

Waterfowl Use in Relation to Size and Cost of Potholes