Before implementing nontoxic shot requirements for hunting waterfowl and American coots Fulica americana in the United States in 1991, the U.S. Fish and Wildlife Service monitored lead poisoning in waterfowl on federal and state wildlife hunting areas during 1983-1986. Federal and state collaborators collected gizzards and livers from 9,029 hunter-killed waterfowl (10 species of dabbling ducks Anatinae, 9 diving ducks Aythyinae, 5 geese Anserinae, and tundra swans Cygnus columbianus) across the four flyways. At the U.S. Fish and Wildlife Service National Wildlife Health Center, Madison, Wisconsin, waterfowl gizzards were examined for ingested lead and nontoxic shot and livers were analyzed for lead concentrations. Diving ducks had the greatest frequency (8.7%) of one or more ingested lead shot, followed by dabbling ducks (5.5%) and geese (1.3%). No ingested shot were found in tundra swans. The frequency of elevated (≥ 2.0 mg/kg wet weight) liver lead concentrations was also greatest in diving ducks, followed by dabbling ducks and geese. Within each species group, the frequency of elevated liver lead concentrations was greater than ingested lead shot, an indication that lead shot ingestion alone underrepresents lead exposure. Thus, lead in the liver may remain elevated after the erosion and excretion of lead pellets from the gizzard. Our results provide historical baseline data and summarize a nationwide study of lead exposure, using both ingested lead shot and liver lead concentrations, in waterfowl in the United States before the implementation of nontoxic shot regulations in 1991. These data can be compared with previous studies of lead exposure in waterfowl, as well as current and future assessments to evaluate the success of nontoxic shot regulations nationwide and specifically within previously sampled waterfowl management areas.
Due to the steady decline of waterfowl hunters, several studies have investigated means to bolster the waterfowl hunter population. Documented declines in waterfowl hunter participation are particularly worrisome as funding for the conservation of North American waterfowl habitat is dependent on the annual purchase of Federal Migratory Bird Hunting Conservation Stamps by is dependent on the annual purchase of Federal Migratory Bird Hunting Conservation Stamps by migratory bird hunters. One method of recruiting new waterfowl hunters is through mentoring by existing members of the hunter population. These mentors serve an important role in the propagation of waterfowl hunting participation and the continued funding of waterfowl conservation. Given the importance of mentors to hunter participation, we sought to discover at what age hunters were most likely to mentor new individuals. Using data from a survey of Central Flyway waterfowl hunters, we found that during the time of the survey, between the ages of 20 and 50 years had a ~0.50 probability of taking someone waterfowl hunting who had never gone before. Hunters in their sixties, seventies, and eighties had a 0.20, 0.24, and 0.18, respectively, probability of mentoring a new hunter. If increasing the waterfowl hunter population remains a goal wildlife agencies, recruitment programming may wish to consider the promotion of mentoring activity by existing hunters well before the age of 60 years.
American black ducks Anas rubripes (hereafter, black ducks) are an important game species in the eastern United States (U.S.) and Canada that declined between the 1950s and 1990s, which resulted in the implementation of restrictive hunting regulations in the United States and Canada. Black duck harvest is managed by the Black Duck International Adaptive Harvest Management (BDAHM) strategy that was developed between Canada and the U.S. The strategy requires that the black duck population be maintained at a level that is commensurate with legal mandates, provides for use appropriate for the habitat carrying capacity, and managed in a manner that maintains equitable access (between Canada and the U.S.) to the black duck resource. Fulfilling these mandates requires unbiased country-specific harvest probability estimates, which in turn require estimates of band reporting probability, that is, the probability that a hunter who harvests a banded bird will report it to the North American Bird Banding Program (NABBP; i.e., either the US Bird Banding Lab (BBL) or Canadian Bird Banding Office (BBO)). We conducted a reporting probability study during the 2017-18, 2018-19, and 2019-20 hunting seasons, using reward bands to estimate continental and country-specific band reporting probabilities. The continental (pooled) band reporting probability was 0.80 (0.660–0.945, 95% confidence interval). Band reporting probability was lower in Canada 0.65 (0.487—0.821, 95% CI) than in the United States 1.00 (0.978–1.022, 95% CI), but increased in both countries since they were last estimated in the 2000s. Increased reporting probability, as well as the difference in reporting between the two countries, should be accounted for to most effectively meet the objectives of the BDAHM strategy.
Beaver Castor canadensis create ecological refugia against drought, heat stress and fire, and policies to support beaver conservation and recolonization in regions where they have been historically extirpated are increasingly common. Between prolonged periods of drought, arid regions are increasingly challenged by extreme precipitation events that promote flash floods, debris flows, and mudslides—a phenomenon known as “whiplash weather”. Understanding how beaver wetlands respond to whiplash weather will help inform the development of restoration policies targeting the species as a natural climate solution. We used remotely sensed normalized difference vegetation index data to characterize the influence of beaver complexes on riparian greenness dynamics under whiplash weather by comparing three complexes and five nearby reference areas along the Salinas River, California. Our study region is within a remanent patch of the historic range of beaver and is highly impacted by agricultural and urban uses. Despite these limitations to expansion and their low density due to historical extirpation, the Salinas River beaver complexes demonstrated greater riparian greenness resistance to drought and resilience to flood disturbance than the watershed reference areas. Thus, policies supporting beaver re-colonization—even within highly fragmented and anthropogenically impacted habitats—may confer both riparian resistance and resilience to increasingly erratic climatic conditions.
In the early 1900s, wood duck Aix sponsa populations experienced severe declines due to unregulated hunting and habitat destruction. Federal protection under the Migratory Bird Treaty Act of 1918 and the implementation of nest box programs facilitated their recovery such that sport harvest resumed in 1941. In 2008, the bag limit for wood ducks during the general duck season increased from two to three daily, a change projected to increase the harvest rates. However, estimating harvest and survival rates of adult females remains challenging due to the difficultly of capturing them during preseason banding operations. We analyzed data from 2001-2014 from box-nesting female wood ducks in Louisiana using a live-dead model to estimate survival and calculate harvest rates. Our results indicate the bag limit increase had minimal impact on the survival and harvest rates of box-nesting females. The mean annual survival rate was 68%, with no changes after the increase in bag limit in 2008. Harvest rates also remained consistent across the study period, averaging 3%. Our findings suggest the increase in bag limit has not adversely affected survival of box-nesting wood ducks in Louisiana, allowing for additional hunting opportunities without compromising conservation goals for adult female wood ducks in the state.
A piscicide delivery method was designed to selectively target Black Carp Mylopharyngodon piceus, an invasive fish species in North America, which possesses pharyngeal teeth adapted for crushing mollusk prey. Many North American mollusks exist in small, fragmented populations susceptible to local extirpation. A Black Carp-selective toxic bait deployed properly could be used to protect those populations. Results represent initial efforts to construct an effective single-dose species-selective toxic bait. We prepared a bait by attaching a glass vial containing toxicant (antimycin A) to the exterior of a Corbicula fluminea clam valve. We designed the vial to break from the force of the fish’s pharyngeal teeth when attempting to crush and consume the clam. We tested suitable vial sizes for encapsulating piscicide and two attachment materials, an aquarium epoxy and ultraviolet light-cured attachment material. The aquarium epoxy was rigid and reinforced vials. The ultraviolet light-cured attachment material was softer, resulting in more vials broken at 3- and 24-h post feeding. In a second trial, toxic baits consisting of antimycin A piscicide were administered in pure ethanol and acetone carriers to Black Carp in assembled baits with vials attached to live clam valves at three concentrations (40.0 mg/mL in ethanol, 170.8 mg/mL and 341.5 mg/mL in acetone). We selected aquarium epoxy for assembled baits based on the bond between the epoxy and glass vial, which allowed a greater surface area to be exposed and broken. While Black Carp successfully broke vials containing piscicide, no treatment caused carp mortality. The delivery method was unsuccessful as a single dose antimycin A piscicide bait for Black Carp. Additional considerations for this approach are provided.
We undertook a study to evaluate the effect of electroshock-induced spinal injury on survival and growth of adult Northern Pike Esox lucius. Our study was conducted on 210 (140 treatment, 70 control) wild adult fish. We exposed treatment fish to 5 s of 120-Hz pulsed DC, then length-measured, x-rayed, double-marked, and released them into 0.04-ha ponds. X-ray images of all fish were evaluated for spinal injury. Of the 140 shocked fish, 28% were injured. After 37 days (9 May – 15 June 1991), the ponds were drained, and 193 surviving fish collected for estimates of short-term survival. Most of these fish (154) were deemed healthy and relocated to a 25-ha lake. After 290 days (15 June 1991 – 1 April 1992), we used gill nets to obtain recaptures for estimates of growth and long-term survival. For both shocked and control fish, short-term survival was in the low 90-percent range and long-term survival was in the low 40-percent range with no difference in survival between shocked and control fish. After 290 d, growth of shocked and control fish was not different. Long-term survival was significantly length dependent: Of the 154 fish released, 42% survived and were significantly larger at initial measurement than that of the 58% that did not. Despite electroshock and injury having no apparent effect on survival and growth, it is essential that injury be minimized. Based on our results, we advise against using 120-Hz pulsed DC electrofishing Northern Pike. Based on results in other studies, we recommend using 60-Hz pulsed DC.
Cambridge Bay, Nunavut, hosts Canada’s largest Arctic Char Salvelinus alpinus commercial fishery with waterbody-specific quotas managed under one Integrated Fisheries Management Plan that emphasizes ecosystem-based management and the need to understand bycatch in the fishery. Bycatch reporting in the fishery, however, remains deficient. In this study, we report on fish, invertebrate, and marine mammal bycatch recorded in logbooks from 2012-2018 at two commercial waterbodies fished using weirs (Halokvik, Jayko) and two fished using gillnets (Surrey, Ekalluk) in multiple Arctic char habitats (rivers, lakes, estuaries). Arctic Char not retained for commercial purposes (discards or those kept for subsistence) comprised the greatest amount of bycatch. Other bycatch included seven fish species(n = 633), one crab species (n = 5), and two seal species (n = 11). Weir fisheries had minimal non-target bycatch, with Halokvik reporting none and Jayko only one species. Gillnet fisheries exhibited the highest bycatch diversity, particularly at the Surrey estuarine fishery. Significant inter-annual variation in the amount of non-target bycatch was also observed at three of the four waterbodies. These findings offer insights for ecosystem-based management for this fishery, while providing a baseline for future monitoring.
Knowledge of species distributions is critical for conservation, but surveying for rare, understudied species presents many challenges. A two-phase occupancy study can increase knowledge gained from early occupancy studies of a species by quickly using data from the first survey period to revise the study design for a second period. The Temblor legless lizard Anniella alexanderae is a recently described fossorial species found in the southwestern San Joaquin Valley, California, and its status is currently under review by state and federal wildlife agencies. As a fossorial species that is rarely surface active, Temblor legless lizards might be unavailable for detection at certain times of year or under inhospitable conditions (e.g., hot, dry weather), indicating the importance of accounting for false-negative surveys when determining its distribution. We used a multiscale occupancy model to disentangle detection probability, availability for detection, and occupancy for Temblor legless lizards. Focusing our effort from mid-February to mid-April when temperatures are mild and soil moisture is expected to be higher near the surface, we surveyed a total of 89 sites in 2022 (n = 60) and 2023 (n = 68) and detected Temblor legless lizards at 12 sites, including 5 new localities. Detection probability was positively related to temperature during our late winter-early spring survey period, and availability for detection was consistently high with minimal fluctuation within each year. Nevertheless, repeated surveys with nondetection can increase confidence that this fossorial lizard does not occur at a site. Temblor legless lizards were more likely to occur at sites near ephemeral streams and in areas without high clay soil content, but more investigation could help to discern drivers of occurrence. Our study provides valuable information for optimizing surveys for Temblor legless lizards and suggests promising directions for future research on this species' ecology.
Definitively identifying bats based on their acoustic calls is difficult and sometimes impossible. This is particularly true for Myotis species that can make similar calls, which could lead to false positive detections. This is problematic for conducting species presence or probable absence surveys using acoustic detection. Manual vetting of calls to reduce identification error by the automated programs is an option but not a requirement to survey for species listed as threatened or endangered pursuant to the Endangered Species Act. We conducted simultaneous mist net and acoustic surveys for bats in areas of Edgecombe and Johnston counties in eastern North Carolina where there are capture records of a common Myotis species, the southeastern myotis Myotis austroriparius, but not for the federally endangered northern long-eared bat Myotis septentrionalis. We caught southeastern myotis at six of the 12 sites surveyed. Although automated acoustics software produced a Maximum Likelihood Estimation value for probable presence of northern long-eared bats at three of the 12 sites surveyed, we did not catch any individuals or confirm the species acoustically through manual vetting. If we had used automated software alone without manual vetting, we would have incorrectly presumed presence of an endangered species at 25% of our sites. Therefore, manual vetting is highly recommended for northern long-eared bat acoustic surveys where southeastern myotis co-occur.
Animals migrate to access seasonally variable resources or to escape unfavorable local conditions. Partial (flexible) migration strategies offer animals a fitness trade-off in which individuals may choose whether to incur the energetic costs of migration depending on the potential benefits associated with avoiding adverse conditions. Partial migration patterns may shift because of anthropogenic land use and climate change, possibly reducing the benefits of migration and resulting in unpredictable migration cues. We examined causes, consequences, and changes in individual-level partial migration of white-tailed deer Odocoileus virginianus by analyzing archival telemetry data (1986-2014) across four distinct populations in the Great Lakes region, North America. We hypothesized that if the costs of migration outweigh benefits, we would see migratory behavior decline. Migratory behavior declined from 75% in 1987 to 11% in 2014 independent of population identity. Annual mortality was higher for migratory white-tailed deer, whereas increasing minimum temperatures positively impacted survival but did not influence migration. Our results suggest that migratory behavior in white-tailed deer is declining over time and may be associated with declining winter severity. The loss of migratory behavior in large mammals may have ecosystem-level impacts and our study emphasizes the need to better understand and conserve these migratory traditions.
The management of anadromous fishes is inherently complicated because this suite of species exhibits complex life histories in multiple habitats and is subject to varying natural and anthropogenic influences during discrete ontogenetic periods. Fishery scientists and managers often adopt life history-based simulation models to help understand potential effects of management decisions on fish populations while incorporating uncertainty in life history, climate, and other components of resource management systems. We applied one such model to Blueback Herring Alosa aestivalis in the Hudson River watershed, New York, USA. Our goal was to better understand influences of historical habitat loss on anadromous fishes and determine to what extent and under what conditions novel habitat created by canal infrastructure might confer increased population abundance. We found that access to historical habitat in the upper Hudson River increased population abundance at all upstream dam passage rates with sufficient downstream survival of adult and juvenile Blueback Herring but that abundance decreased with increasing upstream passage relative to the "no passage" scenario when downstream survival through dams was not sufficiently high. Access to novel spawning habitat in the Mohawk River canal system resulted in increased abundance of Blueback Herring when downstream survival of adults and juveniles was at least 0.80/dam, and both upstream passage and probability of using the Mohawk River were greater than approximately 0.25. Both mortality during upstream passage of locks in the Mohawk River and marine fishery mortality had the potential to reduce Blueback Herring abundance below historical population abundance, despite access to novel spawning habitat. These results highlight the complexity associated with effects of upstream and downstream fish passage standards on population responses while emphasizing similarities observed in other diadromous species and watersheds.
American alligators are an important component of the Greater Everglades, serving as ecosystem engineers, predator, and prey and are tightly tied to water depth patterns. Because of their importance to ecosystem function and link to hydrology, American alligators are an ecological indicator for Everglades restoration. I used data from fall nighttime spotlight surveys of American alligators in the Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida, to describe the trend in number of hatchling pods from 1998 to 2021 and relate that trend to hydrologic parameters hypothesized to influence American alligator production. I used an information-theoretic approach to evaluate 14 models created from combinations of year of observation and three hydrologic variables: average and range in water depth from 16 April of the previous year to 15 April of the nesting year (breeding potential window) and average water depth from 16 April to 31 May of the nesting year (courtship and mating window). Number of pods ranged from 16 in 1998 to 0 in 2011. Each of the four top models included year and one or more of the hydrologic variables as predictors and explained 26-34% (D-squared) of the variation in number of pods. Year was the predictor for which the 95% confidence interval (CI) did not contain 0 and indicated a declining trend (from -3 to -8%; 95% CI). I included all hydrologic variables in the top models, indicating that they contribute some information to explaining the trend; however, contrary to my hypotheses, there was not a clear relationship between any of the hydrologic variables and number of American alligator pods. I based my hypotheses on information synthesized in the American alligator production suitability index model used in Everglades restoration planning, and my results suggest the need for additional refinement of that model.
Agencies commonly stock Muskellunge Esox masquinongy to maintain or augment populations throughout much of North America. Muskellunge poststocking survival is variable, and adult populations are vulnerable to periodic lapses in recruitment. Radiotelemetry evaluated whether changes in stocking techniques caused recruitment declines of spring-stocked yearling Muskellunge in Spirit Lake, Iowa, or whether total length, condition, or 10-d dispersal influenced poststocking survival. The workers fitted hatchery-reared Muskellunge (38-40 fish; n = 78 fish in total) with radio transmitters and stocked in May 2016-2017 by using one of two techniques: 1) fish stocked immediately following 6-h transport in a hatchery distribution truck with Edwards treatment-laden water or 2) fish provided 36-h recovery period after a hauling event and then stocked. Radiotelemetry revealed that stocking techniques did not influence Muskellunge survival or dispersal, but survival significantly improved for fish stocked at larger sizes. Using this information, production techniques in 2018-2019 included an additional 33-40-d rearing period for Muskellunge less than 330 mm when measured for total length in mid-May. We radiotagged a subset of these fish (14-16 fish/y; n = 30 fish total), and survival improved to more than 73.4%. Subsequent application of telemetry was via a side-by-side comparison in 2020 for greater than or equal to 330-mm Muskellunge fitted with radio transmitters and stocked in May (n = 17 fish) and those reared using the grow-out procedure and stocked in June (n = 21 fish). Both cohorts experienced poor survival (39.2-56.1%), resulting from both fish and great blue heron Ardea herodias predation, despite large differences in dispersal. Regardless of stocking technique, this study identified that most mortality occurred within the first 25 d poststocking. These results indicate that Muskellunge populations in natural lakes would benefit from a better understanding of poststocking survival and stocking practices that minimize predator threats during this critical period.
Visible implant alphanumeric (VIA) tags can be beneficial in studies where individual fish must be uniquely identifiable and other tagging methods are not feasible. We examined the feasibility of tagging the endangered Rio Grande Silvery Minnow Hybognathus amarus with VIA tags. We evaluated four key aspects related to VIA tagging in Rio Grande Silvery Minnow: 1) fish survival, 2) fish growth, 3) tag retention, and 4) tag legibility. Fish were randomly selected to be VIA tagged and were held in laboratory aquaria for 49 days. Visible implant alphanumeric tagged fish survival was high (96.7%), tag retention was low (36.2%), fish growth was not affected by tagging, and most retained tags were clearly legible (71.4%). Because of low tag retention and application difficulty, VIA tagging may not be applicable to large-scale field studies of small-bodied fishes.
Silver Carp Hypophthalmichthys molitrix is an invasive species found throughout the Mississippi River basin. Efforts have been made to control Silver Carp populations through removal programs and movement barrier implementation. Up to date information on diel, seasonal, and annual movements and habitat use by Silver Carp will benefit these efforts. Studies of Silver Carp movement are prevalent in the upper Mississippi River, Ohio River, and tributaries, but rare in tributaries of the lower Mississippi River. Between June 2021 and May 2022, we quantified average movement rates and residency periods of 48 Silver Carp in the free-flowing lower White River and lock-and-dam fragmented lower Arkansas River using passive acoustic telemetry arrays and internal implant acoustic transmitters. We also manually tracked Silver Carp in the two rivers during the four seasons to estimate diel movement rates and use of different habitats. On an annual scale, Silver Carp in the White River moved at faster rates than Silver Carp in the Arkansas River and were recorded more times by acoustic receivers. Diel movement rates varied by season in both rivers but were low overall. Silver Carp used lentic habitats more often than lotic habitats. Overall, results suggest the numerous locks and dams of the McClellan-Kerr Arkansas River Navigation System may limit large-scale, annual movement of Silver Carp in the Arkansas River compared to the White River. Low hourly diel movement rates and high occupancy of lentic habitats also should enable effective harvest of Silver Carp using active gears in those lentic habitats.
The montane vole Microtus montanus is a locally abundant rodent that is associated with grassy areas that provide cover for its runways. The Arizona montane vole Microtus montanus arizonensis is a subspecies restricted to the White Mountains region of east-central Arizona and adjacent areas of New Mexico, where it is listed as endangered. The goal of this study was to determine the distribution of the vole in New Mexico and identify habitat characteristics. We surveyed for the vole in New Mexico during 2004 and 2020. In addition, we collected landscape scale habitat and microhabitat data during surveys for voles in New Mexico, as well as during a separate small mammal study conducted in Arizona during 2008 and 2009. We documented voles at 11 new sites in New Mexico based on field surveys and examination of museum specimens. In 2020 we only detected voles at one site where it was historically documented, representing an 83% decline. There was moderate evidence that stream reaches where montane voles were captured had higher vertical cover and suggestive evidence that these reaches had more cover of shrubs than reaches where they were not captured. Microhabitat at capture locations had saturated soil, low canopy cover, high vertical cover, and ground cover dominated by sedges. Vertical cover was higher and Arizona montane voles were more likely to be captured at sites where livestock grazing was not permitted. We conclude that livestock grazing management has resulted in the near extirpation of this small mammal from New Mexico.
The federally threatened southeastern beach mouse Peromyscus polionotus niveiventris occupies just a fraction of its former range along Florida's Atlantic coast, mostly within the 72 km of continuous coastline on federal lands of the Cape Canaveral Barrier Island Complex. Although believed to be caused by loss and degradation of habitat associated with human urban expansion, no precise explanation for the reduction in southeastern beach mouse range is known. We used nine years of winter habitat occupancy survey data for a trend analysis, and a subset of four years to identify key factors influencing occupancy dynamics in coastal habitat throughout the core population. Using a maximum likelihood based model selection approach, we tested evidence for the effects of environmental and anthropogenic factors arranged into four hypotheses related to habitat structure, beach erosion, population isolation, and access to inland habitat. As predicted, sites closer to the primary dune, farther from open water, and with higher elevation had higher initial occupancy than sites with the opposite characteristics. Also as predicted, sites farther from open water, with higher elevation, more coastal strand, less ruderal vegetation, and in proximity to oak trees had lower site extinction. Contrary to predictions sites closer to infrastructure (roads, railroads, paved sites) and more isolated by narrow width or unsuitable habitat features also had lower extinction, possibly because of restriction of predator access. A Bayesian analysis showed that annual southeastern beach mouse habitat occupancy was generally high (0.63-0.97) but variable across the 72 km of coastal dune spanning most of the remaining species' range. Simulation showed that the power of the survey was sufficient to detect a 20% decline between years. This study provides a baseline of knowledge about habitat occupancy dynamics for future monitoring and management of the southeastern beach mouse and other beach mouse subspecies.
Sylvatic plague, caused by the flea-borne bacterium Yersinia pestis, is an invasive disease in North America that causes reductions of native fauna and transforms ecosystems. Fipronil baits have shown promise in reducing flea loads on prairie dogs Cynomys spp. for plague mitigation. Many species depend on prairie dogs and their ecological influences, including the black-footed ferret Mustela nigripes (ferret), an obligate predator of prairie dogs. To better understand how fipronil affects ferrets, we offered carcass portions from black-tailed prairie dogs C. ludovicianus that had consumed fipronil bait (0.005% fipronil by weight) to captive ferrets and monitored their health. We fed carcass portions of three prairie dogs to four adult ferrets for 1 week. No ill effects were observed in the ferrets. We collected scat from the ferrets before, during, and after their feeding on treated prairie dogs. We evaluated potential effects of ferret scat on larval fleas, which feed on organic matter. Fipronil residues were not detected in ferret scat samples collected before treatment. During and shortly after treatment, ferret scat contained 3.76 ng/g fipronil and 13.75 ng/g fipronil sulfone, on average, demonstrating trophic transfer of the residues from prey to predator. We presented 0.5 mg of ferret scat to each of 96 larval Oropsylla montana (Siphonaptera: Ceratophyllidae) and assessed survival rates over 24 h. When exposed to ferret scat lacking fipronil residues, 85% of larvae survived. Survival was reduced to 61% and 35% for larvae contacting or consuming scat with fipronil residue, respectively. Fipronil residues in scat from a variety of species on prairie dog colonies, perhaps especially the prairie dogs, may assist in flea control and plague mitigation. Hosts eliminate fipronil residues, and fipronil residues in the environment degrade over time, reducing but not eliminating potential concerns with bioaccumulation.
anagers often use mechanical disturbance in conjunction with, or in place of, prescribed fire to maintain pyrogenicplant communities in the southeastern United States. However, information on the effects of mechanical fire-surrogateson disturbance-dependent wildlife is lacking. The Florida scrub-jayAphelocoma coerulescensis an endemic bird speciesreliant on Florida scrub, a pyrogenic shrubland plant community narrowly distributed on sandy ridges in peninsularFlorida. Ocala National Forest in north central Florida supports the largest remaining population of Florida scrub-jays,and historically, maintenance of most scrub habitat at the site is through the commercial harvest (clearcutting) ofmature sand pinesPinus clausa. Recently, a habitat restoration program established Scrub-Jay Management Areas byconverting clearcut stands to scrub maintained in an early-successional condition by prescribed fire. We studied Floridascrub-jays in Scrub-Jay Management Areas (2016-2023) to better understand how family-group density changed overtime since fire management compared with time since harvest in clearcut stands. In scrub treated with prescribed fire,Florida scrub-jay family-group density increased more rapidly postdisturbance and was consistently higher than inclearcut stands. Based on model predictions, the maximum mean density of family groups occurred at 8.5 y postfire(11.8 family groups/41 ha) in Scrub-Jay Management Areas and 6.2 y postharvest (5.5 family groups/41 ha) in clearcutstands. Our study provides the first quantitative data on the response of Florida scrub-jay populations to new forestmanagement practices in this large and critically important population. These data provide an essential component fordeveloping population models for Ocala National Forest under current conditions and for modeling the potentialeffects of future management decisions
