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The miniaturization of Global Positioning Systems (GPS) transmitters is providing insights into the ecology and management of migratory bird species at biologically‐relevant spatial scales. However, transmitters and their attachment methods could bias inferred behaviors, demographic rates, and resulting management decisions. We evaluated the effects of external harness‐style GPS transmitters by comparing direct harvest rates, winter dispersal distances, and subsequent harvest distributions of mallards (Anas platyrhynchos) equipped with GPS transmitters (n = 443) to a tarsal banded‐only control group (n = 1,123) captured in western Tennessee during winters 2019–2022. We found that transmitter‐marked mallards had similar harvest rates, winter dispersal distances, and harvest distributions as banded‐only mallards. Time between capture and harvest predicted dispersal distances but there was no effect of marker type. Specifically, the average time from capture to harvest was 30 (SE = 2) and 31 (SE = 3) days for banded‐only and transmitter‐marked mallards, respectively. Harvest rate (h ) was only 2.2% greater for transmitter‐marked mallards compared to banded‐only mallards overall, but GPS transmitters affected harvest susceptibility of juveniles (∆hjuv = 14.5%). Based on harvest rates and dispersal distances between transmitter‐marked and banded‐only cohorts, we suggest 7‐ to 10‐day data censoring periods may be warranted, especially for juveniles, as mallards acclimate to GPS transmitters. Overall, we concluded that modern harness‐style GPS transmitters provided reliable information of wintering mallard space use, movements, and harvest mortality and can be used to inform ecology and management of wintering mallards and other dabbling ducks. Future studies should evaluate effects of harness‐style GPS transmitters for other species and during different portions of dabbling ducks' life cycle, such as migration or nesting, when they may experience greater adverse effects. [ABSTRACT FROM AUTHOR]

Extreme climatic events (ECEs) can have profound impacts on individual fitness, affecting survival directly or indirectly. Late winter ECEs may be especially detrimental to fitness due to limited food resources and increased energetic requirements during this time. A polar vortex disruption ECE descended upon the mid-continental United States during February 7–20, 2021 with temperatures as low as −29°C in areas concurrent with ongoing research on Anas platyrhynchos (Mallard) movement ecology and survival in Arkansas, Louisiana, and Tennessee, United States spanning winters 2019–2022. Therefore, we opportunistically evaluated the effects of individual characteristics and latitude on daily survival during the ECE. We extended the survival analysis to March to test for lasting effects of the ECE on survival. We tracked 181 Global Positioning System (GPS)-marked A. platyrhynchos during February 2020, 256 in February 2021, and 324 in February 2022. We documented 22 mortalities during the February 2021 ECE (i.e. 9%), but only 6 mortalities during February 2020 (i.e. 2%) and 2022 (i.e. 1%) when conditions were average. February survival (e.g. 28-day survival) during the ECE was 0.908 (85% CI: 0.879–0.937) but was 0.982 (85% CI: 0.973–0.991) during the 2 non-ECE Februaries. The ECE effect on survival was isolated to February and did not affect March survival. Anas platyrhynchos was 5.4 times more likely to die during the ECE in 2021 compared to non-ECE Februaries. Although large-bodied waterfowl appear cold-tolerant and less sensitive to polar vortex disruptions compared to smaller-bodied passerines, direct mortalities can occur if conditions are severe enough and persist, highlighting the need to consider the influence of ECEs on common, seemingly robust species in future global climate change scenarios. [ABSTRACT FROM AUTHOR]

The spatiotemporal allocation of activity is fundamental to how organisms balance energetic intake and predation risk. Activity patterns fluctuate daily and seasonally, and they are proximately affected by exogenous and endogenous conditions. For birds, flight activity is often necessary for relocating between foraging patches but is energetically expensive and can increase mortality risk. Hunted species may have to adjust their behavior and activity patterns to minimize anthropogenic mortality risk. We used hourly locations from 336 GPS-marked mallards Anas platyrhynchos to examine how hunting pressure affected flight activity in response to weather conditions and habitat availability during winter in western Tennessee, USA. Mallards were more likely to fly during crepuscular times, particularly dusk, across winter months. Mallards conducted more flights after shooting hours when habitat availability increased during open hunting season; conversely, mallard flights decreased with increasing habitat availability when hunters were present on the landscape. Mallards were least active during periods open to hunting. However, indicators of approaching inclement weather (i.e. increased wind speed, precipitation, and decreasing barometric pressure) increased flights during periods open to hunting. Mallard flights decreased at lower temperatures except when hunting season was closed, wherein mallards increased nighttime flights. Flight activity was directly influenced by hunting disturbance which constrained when and how mallards reacted to environmental and habitat conditions. An understanding of the temporal shifts in waterfowl flight patterns can be used by natural resource managers to better manage stakeholder satisfaction and expectations. [ABSTRACT FROM AUTHOR]

The North American Waterfowl Management Plan (NAWMP) recognizes waterfowl hunters and non‐consumptive users as important stakeholders to sustain waterfowl populations through economic and political support for habitat conservation initiatives. Opportunities to shoot at and harvest ducks are key determinants of achievement‐oriented hunt satisfaction and quality. Therefore, identifying factors influencing harvest opportunity would help hunters and wildlife managers identify optimal days afield and promote hunter recruitment, retention, and reactivation (R3) efforts in support of NAWMP. Waterfowl extensively use spatial sanctuaries during hunting seasons, especially diurnally, which could limit their perceived availability to hunters. Thus, a possible management action to support R3 is allowing limited public access on sanctuaries, which could offer diverse recreational opportunities for non‐consumptive users and potentially increase harvest opportunities for hunters in traditional hunting areas if the limited disturbance caused waterfowl to leave sanctuaries. Therefore, we evaluated to what extent experimental sanctuary disturbance, landscape characteristics, and weather influenced local harvest opportunities. We conducted disturbance treatments including travel by a covered truck (i.e., truck with enclosed cab), a pedestrian on foot, and an uncovered vehicle (e.g., motor boat or all‐terrain vehicle [ATV]). To measure harvest opportunity, we used autonomous recording units (ARU) to enumerate daily shotgun volleys at a landscape‐scale across western Tennessee, USA, during 2019–2021 waterfowl hunting seasons. We identified 339,391 distinct shotgun volleys (x¯ $\bar{x}$ = 73 shotgun volleys/day/ARU). Shotgun volleys decreased 50% within 2 weeks of opening day and did not notably increase for the remainder of the hunting season. Contrary to our predictions, sanctuary disturbance decreased harvest opportunity. Specifically, the pedestrian disturbance and covered vehicle disturbance decreased daily shotgun volleys by 32% and 31%, respectively. Additionally, harvest opportunity decreased 20% with every 5‐km increase in distance from a sanctuary. Harvest opportunity increased 2% for every 1°C decrease from mean low temperatures and 9% with every 10‐hPa increase in barometric pressure from the previous day. Conversely, harvest opportunity was unaffected by changes in cloud cover, daily precipitation, waterfowl abundance, or surface water inundation. Our results suggest disturbing sanctuaries decreases harvest opportunity and, in turn, may reduce hunt quality and satisfaction. If increasing harvest opportunity is a primary management objective, we recommend limiting sanctuary disturbance to maximize local harvest opportunities. Furthermore, greater harvest opportunity nearer sanctuaries indicates that additional disturbance‐free areas may increase local harvest opportunities and hunter satisfaction. [ABSTRACT FROM AUTHOR]

The theory of adaptive habitat selection suggests resource selection by animals should reflect underlying quality, such that individual selection confers an adaptive advantage via increased fitness. Using resource selection functions and nest survival models, we demonstrated that visual obstruction at the nest site was adaptively significant but timing of nest initiation had the greatest effect on nest survival for eastern Wild Turkeys (Meleagris gallopavo silvestris). Predation risk is a selective pressure, and if individuals can perceive predation risk, they may respond by altering the selection of nest site characteristics based on prior experience. We evaluated patterns in nest site selection of 387 Wild Turkeys and the consequences of selection on reproductive success across the southeastern United States from 2014 to 2019. We monitored 549 nest sites and found that nest initiation date had the strongest effect on daily nest survival rates, wherein adult females at our earliest nest initiation date were ~4 times more likely to successfully nest than females at our latest nest initiation date. Selection of nest sites with greater visual obstruction also increased daily nest survival rates, and females were 1.17 (95% CI: 1.100-1.234) and 1.37 (95% CI: 1.258-1.486) times more likely to select sites for every 10-cm increase in visual obstruction and maximum vegetation height, respectively. Collectively, our results indicate that nest initiation date is likely the critical parameter driving Wild Turkey nest success, whereas vegetative conditions play a lesser role in influencing nest success. Females nesting earlier may be in better body condition and show increased nest attentiveness, which may mediate nest success more than vegetation conditions around nest sites. Our work indicates that increasing the reproductive success of Wild Turkeys may hinge on females being able to nest as early as possible within the reproductive season. [ABSTRACT FROM AUTHOR]

Introgressive hybridization, the interbreeding and gene flow between different species, has become increasingly common in the Anthropocene, where human-induced ecological changes and the introduction of captively reared individuals are increasing secondary contact among closely related species, leading to gene flow between wild and domesticated lineages. As a result, domesticated-wild hybridization may potentially affect individual fitness, leading to maladaptive effects such as shifts in behavior or life-history decisions (e.g., migration patterns), which could influence population demographics. In North America, the release of captive-reared game-farm mallards ( Anas platyrhynchos ) for hunting has led to extensive hybridization with wild mallards, altering the genetic structure in the Atlantic and Mississippi flyways. We aimed to investigate differences in spring migratory behavior among 296 GPS-tagged mallards captured during winter in Tennessee and Arkansas with varying levels of hybridization. Despite relatively low levels of genetic introgression of game-farm genes, mallards with higher percentages of game-farm ancestry exhibited later departure and arrival times, shorter migration distances, and a tendency to establish residency at lower latitudes. Specifically, for every 10% increase in game-farm genetics, mallards departed 17.7% later, arrived 22.1% later, settled 3.3% farther south, and traveled 7.1% shorter distances during migration. These findings suggest that genetic introgression from game-farm mallards influences migratory behavior, potentially reducing fitness, and contributing to population declines in wild mallards. Our study presents a need for understanding how domestic hybridization effects fitness and behavioral change of other species., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Ecology and Evolution published by John Wiley & Sons Ltd.)