Academic literature on the topic 'Mallard. Wildlife management'

Wildlife conservation plans generally require reliable data about population abundance and density. Aerial surveys often can provide these data; however, associated costs necessitate designing and conducting surveys efficiently. We developed methods to simulate population distributions of mallards (Anas platyrhynchos) wintering in western Mississippi, USA, by combining bird observations from three previous strip-transect surveys and habitat data from three sets of satellite images representing conditions when surveys were conducted. For each simulated population distribution, we compared 12 primary survey designs and two secondary design options by using coefficients of variation (CV) of population indices as the primary criterion for assessing survey performance. In all, 3 of the 12 primary designs provided the best precision (CV ≤ 11.7%) and performed equally well (diff ≤ 0.6%). Features of the designs that provided the largest gains in precision were optimal allocation of sample effort among strata and configuring the study area into five rather than four strata, to more precisely estimate mallard indices in areas of consistently high density. Of the two secondary design options, we found including a second observer to double the size of strip transects increased precision or decreased costs, whereas ratio estimation using auxiliary habitat data from satellite images did not increase precision appreciably. We recommend future surveys of mallard populations in our study area use the strata we developed, optimally allocate samples among strata, employ PPS or EPS sampling, and include two observers when qualified staff are available. More generally, the methods we developed to simulate population distributions from prior survey data provide a cost-effective method to assess performance of alternative wildlife surveys critical to informing management decisions, and could be extended to account for effects of detectability on estimates of true abundance.

Abstract Management of waterfowl habitat and hunting frequency is important to sustain hunting opportunities in Mississippi and elsewhere in North America. Managers have limited scientific information regarding the effect of weekly hunting frequency on waterfowl abundance for use in developing hunting plans for public hunting areas. We divided the hunted portions of three Mississippi Wildlife Management Areas into two treatments to evaluate the effect of hunting 2 versus 4 d/wk on duck abundance. Abundance of all ducks, mallard Anas platyrhynchos, northern shoveler Anas clypeata, and green-winged teal Anas crecca were not detectably different between weekly hunting frequencies. Sanctuary use increased approximately 30% during the first 1.25 h after sunrise regardless of hunting disturbance being present or absent. Our results indicate that duck abundance did not increase with increased rest days at Wildlife Management Areas, suggesting these areas may be hunted 4 d/wk without significantly decreasing duck abundance. Sanctuaries were used daily and may be vital to attract and retain ducks on Wildlife Management Areas.

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.

Abstract Within the U.S. portion of the Central Flyway, the U.S. Fish and Wildlife Service manages waterfowl on numerous individual units (i.e., Refuges) within the National Wildlife Refuge System. Presently, the extent of waterfowl use that Refuges receive and the contribution of Refuges to waterfowl populations (i.e., the proportion of the Central Flyway population registered at each Refuge) remain unassessed. Such an evaluation would help determine to what extent Refuges support waterfowl relative to stated targets, aid in identifying species requiring management attention, inform management targets, and improve fiscal efficiencies. Using historic monitoring data (1954–2008), we performed this assessment for 23 Refuges in Texas, New Mexico, Oklahoma, Kansas, and Nebraska during migration and wintering months (October–March). We examined six dabbling ducks and two diving ducks, plus all dabbling ducks and all diving ducks across two periods (long-term [all data] and short-term [last 10 October–March periods]). Individual Refuge use was represented by the sum of monthly duck count averages for October–March. We used two indices of Refuge contribution: peak contribution and January contribution. Peak contribution was the highest monthly count average for each October–March period divided by the indexed population total for the Central Flyway in the corresponding year; January contribution used the January count average divided by the corresponding population index. Generally, Refuges in Kansas, Nebraska, and New Mexico recorded most use and contribution for mallards Anas platyrhynchos. Refuges along the Texas Gulf Coast recorded most use and contribution for other dabbling ducks, with Laguna Atascosa and Aransas (including Matagorda Island) recording most use for diving ducks. The long-term total January contribution of the assessed Refuges to ducks wintering in the Central Flyway was greatest for green-winged teal Anas crecca with 35%; 12–15% for American wigeon Mareca americana, gadwall Mareca strepera, and northern pintail Anas acuta; and 7–8% for mallard and mottled duck Anas fulvigula. Results indicated that the reliance on the National Wildlife Refuge System decreased for these ducks, with evidence suggesting that, for several species, the assessed Refuges may be operating at carrying capacity. Future analyses could be more detailed and informative were Refuges to implement a single consistent survey methodology that incorporated estimations of detection bias in the survey process, while concomitantly recording habitat metrics on and neighboring each Refuge.

Any human activity, even if aimed at the improvement of a natural area, can potentially affect wildlife, leading to possible short-term or long-term changes due to the human–wildlife interaction. In this study, a botulism outbreak which occurred in waterfowl in a nature reserve after a conservative environmental action is reported. More than 180 different species of wild birds, including seventy waterfowl species, live in the area. The wildlife reserve rangers built an artificial pond equipped with draining canals in the wetland in order to improve the environment of waterfowl species and to facilitate their supply of food. Then, presumably due to tidal rides, gray mullets (Mugil cephalus) arrived from the sea and settled in the pond. The number of fishes gradually increased, and several fishes died with a peak of mortality in the summer of 2017, creating a great amount of decaying organic material and the optimal conditions for Clostridium botulinum growth and toxin production. A botulism outbreak then occurred rapidly and was characterised by flaccid paralysis and sudden mortality of the birds. Seven mallard ducks (Anas platyrhynchos), 4 common teals (Anas crecca), 1 garganey (Anas querquedula), 2 wood sandpipers (Tringa glareola), 1 little egret (Egretta garzetta), 1 little grebe (Tachybaptus ruficollis), and 4 Eurasian coots (Fulica atra) were found dead. Interestingly, the toxin identified as responsible for the disease outbreak was the mosaic of type C and D toxins (C/D type). The prompt removal of the fish carcasses led to a rapid resolution of the outbreak of the disease, highlighting the relevance of a correct management for any action in environmental contexts. The conclusion is that any human activity in wildlife habitats should be carefully considered in order to assess the possible impacts and to quickly identify the possible risks of changes in wildlife population.

Abstract Context Effective wildlife management requires information on habitat and resource needs, which can be estimated with movement information and modelling energetics. One necessary component of avian models is flight speeds at multiple temporal scales. Technology has limited the ability to accurately assess flight speeds, leading to estimates of questionable accuracy, many of which have not been updated in almost a century. Aims We aimed to update flight speeds of ducks, and differentiate between migratory and non-migratory flight speeds, a detail that was unclear in previous estimates. We also analysed the difference in speeds of migratory and non-migratory flights, and quantified how data collected at different temporal intervals affected estimates of flight speed. Methods We tracked six California dabbling duck species with high spatio-temporal resolution GPS–GSM transmitters, calculated speeds of different flight types, and modelled how estimates varied by flight and data interval (30min to 6h). Key results Median migratory speeds were faster (but non-significant) for the larger mallard (Anas platyrhynchos; 82.5kmh–1), northern pintail (Anas acuta; 79.0kmh–1) and gadwall (Mareca strepera; 70.6kmh–1), than the smaller-bodied northern shoveler (Spatula clypeata; 65.7kmh–1), cinnamon teal (Spatula cyanoptera; 63.5kmh–1) and American wigeon (Mareca Americana; 52kmh–1). Migratory flights were faster than non-migratory flights for all species and speeds were consistently slower with an increasing data interval. Implications The need to balance time and energy requirements may drive different speeds for migratory and non-migratory flights. Lower speeds at longer intervals are likely to be due to a greater proportion of ‘loafing’ time included in flighted segments, demonstrating that data acquired at different intervals provide a means to evaluate and estimate behaviours that influence speed estimation. Shorter-interval data should be the most accurate, but longer-interval data may be easier to collect over lengthier timeframes, so it may be expedient to trade-off a degree of accuracy in broad-scale studies for the larger dataset. Our updated flight speeds for dabbling duck species can be used to parameterise and validate energetics models, guide management decisions regarding optimal habitat distribution, and, ultimately, improve conservation management of wetlands for waterfowl.

Context The broad concepts and generalisations that guide conduct of applied ecology, including wildlife management, have been reviewed and synthesised recently into 22 prescriptive and three empirical principles. Aims The aim of this study was to use these principles to evaluate three on-ground wildlife management programs and assess the utility of the principles themselves. Key results Case studies of long-term management of national park biodiversity impacted by feral pigs (Sus scrofa), and of conservation and harvest of red kangaroos (Macropus rufus) and mallards (Anas platyrhnchos), were selected to provide a representative range of management objectives, spatial scales and land tenures, and to include both native and introduced species. Management documents and a considerable scientific literature were available for all three programs. The results highlight similarities and differences among management activities and demonstrate the 25 principles to differing degrees. Most of the prescriptive principles were demonstrated in both the management and the scientific literature in all three programs, but almost no use was made of the three empirical principles. We propose that use of the prescriptive principles constitutes evidence that these programs meet both societal and scientific expectations. However, the limited use of the empirical principles shows gaps in the three programs. Conclusions The results suggest that evaluating other wildlife management programs against the principles of applied ecology is worthwhile and could highlight aspects of those programs that might otherwise be overlooked. Little use was made of the empirical principles, but the the Effort–outcomes principle in particular provides a framework for evaluating management programs. Implications The effort–outcomes relationship should be a focus of future applied research, and both prescriptive and empirical principles should be integrated into wildlife management programs.

AbstractLarge numbers of gamebirds (pheasants Phasianus colchicus, red-legged partridges Alectoris rufa and mallard Anus platyrhynchos) are released annually in the UK to support recreational shooting. It is important to know how many of these birds are being released because their release and management has ecological effects on the wildlife and habitats of the UK. There is little regulation governing their release, and consequently, an accurate figure for the numbers being released is unknown. I took 12 different approaches, totalling 4329 estimates of the numbers of birds being released annually, based on a series of datasets that described numbers of birds being held for breeding, rearing or release, being released, managed or shot on game shoots, being shot by individual guns or being recorded during breeding bird surveys. These 12 approaches produced estimates ranging from 14.7 to 106.1 million with a mean of 43.2 million (95% CI 29.0–57.3 million). This suggests that 31.5 million pheasants (range 29.8–33.7 million), 9.1 million red-legged partridges (range 5.6–12.5 million) and 2.6 million mallard (range 0.9–6.0 million) are released annually in the UK. These figures differ substantially from both official records of gamebirds and previous published estimates, and I discuss why such differences may occur. I set these figures in the context of the number and behaviour of shoots operating in the UK. Improved estimates of numbers of gamebird being released are critical if we are to better understand the ecological effects occurring in areas where they are released and managed.

Interactions between animal populations and their environment form the foundation of wildlife management, and provision of resources that enhance fitness produce effectual management. Hunting is a selective force that shapes behavior and other adaptations of harvested species and may subsequently impact diel habitat use. Moreover, linking habitat use to biological outcomes, such as survival, is needed to evidence habitat suitability because of equivocal relations among population density, habitat correlations, or energy availability to population dynamics. The mallard (Anas platyrhynchos) is among the most coveted and harvested waterfowl in North America and is a migratory species of ecological, economic, and social importance. The Mississippi Alluvial Valley (MAV) is an ancestral and continentally important wintering area for North American mallards despite significant anthropogenic wetland transformation. Through targeted objectives and consequence of soil and water conservation, financial assistance programs have expanded waterfowl habitat on private lands in Mississippi. I radiomarked 265 female mallards and tracked their diel habitat use in winters 2010-2015 to evaluate objectives related to their wintering ecology in the MAV of Mississippi. Specifically, I investigated whether waterfowl hunting influenced use of some habitats during hunting season, the effectiveness of financial assistance programs in providing habitat, and habitat suitability through habitat specific survival rates. Females made greatest use of forested and emergent wetlands diurnally and emergent wetlands and flooded cropland at night. Results suggested that mallards did not avoid flooded cropland or emergent wetlands diurnally during hunting season, but conclusions were complicated by significant use of inviolate sanctuaries. Mallards used numerous incentivized conservation program wetlands, but use was less than public and privately managed wetlands. Among conservation programs, those with large enrollment and a focus on restoration (i.e., Wetlands Reserve Program) were most used by mallards. Apparent survival was independent of diurnal habitat use suggesting that mallards use of wetland complexes leads to their winter survival. Restoration of forested wetlands should be a management focus and easement programs provide such inroads on private lands. Public wetlands are an important source of habitat and inviolate sanctuary should be considered where waterfowl hunting is a predominate activity.

The Mississippi Alluvial Valley (MAV) is an important region for wintering mallards (Anas platyrhynchos) in North America, yet little is known about their spatiotemporal habitat use and related survival in Mississippi. I tracked 126 radio-marked female mallards to quantify survival, habitat use, and use of wildlife management areas (WMAs) with experimental hunt regimes in the south MAV of Mississippi during winters 2010-2012. Daily survival was greatest in agricultural (0.997) and moist-soil (0.999) habitats in winters 2010-2011 and 2011-2012, respectively. Overall interval survival across both winters was 0.60 (SE = 0.02). Forested (40-54%) and moist-soil wetlands (41-59%) received greatest use diurnally and nocturnally, respectively. Mallards used WMAs similarly (P > 0.22) whether they were hunted 2- or 4-days/week. My data suggest that complexes of flooded cropland, forest, and moist-soil habitats are suitable habitats for mallards in the MAV, WMAs can be hunted 4-days/week, and sanctuaries should be revised at two WMAs.