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Effects of open-entry spike-bull, limited-entry branched-bull harvesting on elk composition in Washington

The Washington Department of Fish and Wildlife implemented an open-entry spike-bull, limited-entry branched-bull elk (Cervus elaphus) harvest strategy in the Blue Mountains (1989), Yakima (1994), and Colockum (1994) herd areas of Washington state with goals of increasing numbers of adult bulls to increase breeding efficiency and possibly calf recruitment. Numbers of total bulls/100 cows (x??=5.4) and branched bulls/100 cows (x??=5.3) increased with the change in harvest strategy, while yearling bulls/100 cows remained unchanged; calves/100 cows declined (x??=-8.6). Calves/100 cows were always negatively correlated with both total bulls/100 cows and branched bulls/100 cows in each area; correlations were significant in 5 of 9 comparisons with total-bull ratios and 5 of 9 comparisons with branched-bull ratios. Open-entry spike-bull, limited-entry branched-bull harvesting can be used to increase total-bull and branched-bulls ratios in hunted elk populations. However, the increased ratios of bulls and branched bulls were unimportant in influencing calf recruitment, likely because of the importance of female condition on production and survival of young.

Wildlife Society Bulletin

Blood lead exposure concentrations in mottled ducks ( Anas fulvigula ) on the upper Texas coast

The mottled duck (Anas fulvigula) is a non-migratory waterfowl species dependent upon coastal marsh systems, including those on the Texas Chenier Plain National Wildlife Refuge (NWR) Complex, and considered a regional indicator species of marsh habitat quality. Research from the early 1970s, 1990s, and early-2000s indicated that mottled ducks continued to exhibit elevated wing-bone lead (Pb) concentrations, decades after implementation of non-toxic shot regulations. However, wing-bone concentrations reflect lifetime accumulation of Pb, whereas blood Pb concentrations reflect more recent exposure. To identify current potentially relevant temporal windows of Pb exposure, we collected 260 blood samples from mottled ducks during summer (n=124) and winter (n=136) from 2010–2012 on the Texas Chenier Plain NWR Complex. We quantified baseline blood Pb concentrations for all ages of mottled ducks, and hypothesized that blood lead concentrations would remain elevated above background levels (200 µg L–1) despite the 1983 and 1991 lead shot bans. Blood Pb concentrations ranged from below detection limits to >12,000 µg L–1, where >200 µg L–1 was associated with exposure levels above background concentrations. Male mottled ducks had the greatest blood Pb concentrations (30 times greater than females) with concentrations greater during winter than summer. Likewise, the proportion of exposed (>200 µg L–1) females increased from 14%–47% from summer to winter, respectively. Regardless of sex, adult mottled duck blood Pb concentrations were five times greater than juveniles, particularly during winter. We identified five plausible models that influenced blood Pb levels where year, site, and interactions among age*sex*season and between age*season were included in the top-ranked models. Frequency of exposure was greatest during winter, increasing from 12% in summer to 55% in winter, indicating that a temporal exposure window to environmental Pb exists between nesting and hunting seasons. Blood Pb concentrations remain elevated in mottled ducks despite Pb shot bans enacted >25 years prior to this study. If Pb levels in mottled ducks becomes a conservation concern, regional monitoring of blood Pb concentrations would be appropriate with a focus upon elucidating potential reasons for the variation among age and sex groups. Finally, identifying potentially available sources of environmental Pb may be key to minimizing this apparently persistent threat to mottled ducks on the upper Texas coast.

Journal of the Southeastern Association of Fish an

Complexity and integration of recreational fisheries

Recreational fisheries are interconnected, complex, adaptive systems characterized by multiple direct and indirect interactions among ecological and human subsystems. This is important for many reasons, including that feedbacks between the social and ecological dimensions lead to difficult-to-predict, often entirely unexpected, outcomes and because many management and governance systems have multiple objectives that can involve social (e.g. fisher satisfaction), economic (e.g. license revenue), and ecological (e.g. fish conservation) dimensions. Embracing a social-ecological-system perspective can usher in an improved era of recreational fisheries science and management. Interdisciplinary approaches that unite experts across disciplines (e.g. social and ecological sciences) to create a unique theoretical, conceptual, and methodological identity are needed to gather crucial information from recreational fishers, quantify and predict fisher behaviours and outcomes from these behaviours, and integrate these findings into fisheries management. In this chapter, we lay the conceptual foundation for recreational fisheries as coupled social-ecological systems that are also complex and adaptive, and discuss the interdisciplinary approach to operationalize this book’s vision.

Book chapter

Late Quaternary environmental change in the Bonneville basin, western USA

Excavation and analyses of small animal remains from stratified raptor deposits spanning the last 11.5 ka, together with collection and analysis of over 60 dated fossil woodrat midden samples spanning the last 50 ka, provide a detailed record of changing climate in the eastern Great Basin during the late Pleistocene and Holocene. Sagebrush steppe dominated the northern Bonneville basin during the Full Glacial, suggesting that conditions were cold and relatively dry, in contrast to the southern basin, which was also cold but moister. Limber pine woodlands dominated ???13-11.5 ka, indicating increased dryness and summer temperatures ???6-7??C cooler than present. This drying trend accelerated after ???11.5 ka causing Lake Bonneville to drop rapidly, eliminating 11 species of fish from the lake. From ???11.5-8.2 ka xerophytic sagebrush and shadscale scrub replaced more mesophilic shrubs in a step-wise fashion. A variety of small mammals and plants indicate the early Holocene was ???3??C cooler and moister than at present, not warmer as suggested by a number of climatic models. The diversity of plants and animals changed dramatically after 8.2 ka as many species disappeared from the record. Some of the upland species returned after ???4 ka and Great Salt Lake became fresh enough at ???3.4 and ???1.2 ka to support populations of Utah chub. ?? 2001 Elsevier Science B.V.

Palaeogeography, Palaeoclimatology, Palaeoecology

A decision support tool for adaptive management of native prairie ecosystems

The Native Prairie Adaptive Management initiative is a decision support framework that provides cooperators with management-action recommendations to help them conserve native species and suppress invasive species on prairie lands. We developed a Web-based decision support tool (DST) for the U.S. Fish and Wildlife Service and the U.S. Geological Survey initiative. The DST facilitates cross-organizational data sharing, performs analyses to improve conservation delivery, and requires no technical expertise to operate. Each year since 2012, the DST has used monitoring data to update ecological knowledge that it translates into situation-specific management-action recommendations (e.g., controlled burn or prescribed graze). The DST provides annual recommendations for more than 10,000 acres on 20 refuge complexes in four U.S. states. We describe how the DST promotes the long-term implementation of the program for which it was designed and may facilitate decision support and improve ecological outcomes of other conservation efforts.

Interfaces

Fish out of water: Insights from a case study of a highly social animal that failed the mirror self-recognition test

Mirror self-recognition (MSR) tests have been conducted with a variety of species with the aim of examining whether subject animals have the capacity for self-awareness. To date, the majority of animals that have convincingly passed are highly social mammals whose wild counterparts live in complex societies, though there is much debate concerning what constitutes passing and what passing means in terms of self-awareness. Amid recent reports that a fish (cleaner wrasse, Labroides dimidiatus ) passed, it is intriguing that a mammal as highly social, tolerant, attentive, and cooperative as the grey wolf ( Canis lupus ) reportedly failed the test. Given the many possible reasons for failure, we aimed to elucidate the wolves’ responses at various stages of the MSR test to pinpoint potential problem areas where species-appropriate modifications to the test may be needed. Thus, we evaluated 6 socialized, captive grey wolves as a case study of failed MSR in socially complex canids. At a minimum, wolves did not respond to their reflection as an unfamiliar conspecific. Unfortunately, the wolves rapidly lost interest in the mirror and were uninterested in the applied marks. We note limitations of the MSR test for this species, recommend changes for future MSR tests of wolves, discuss other emerging self-cognizance methods for socially complex canids, and highlight the need for a suite of ecologically relevant, potentially scalable self-cognizance methods. Our findings and recommendations may aid in understanding self-cognizance in other untested highly social, cooperatively-hunting, coursing, terrestrial carnivores such as African wild dogs ( Lycaon pictus ), spotted hyenas ( Crocuta crocuta ), and African lions ( Panthera leo ).

International Journal of Comparative Psychology

Annual survival rate estimate of satellite transmitter–marked eastern population greater sandhill cranes

Several surveys have documented the increasing population size and geographic distribution of Eastern Population greater sandhill cranes Grus canadensis tabida since the 1960s. Sport hunting of this population of sandhill cranes started in 2012 following the provisions of the Eastern Population Sandhill Crane Management Plan. However, there are currently no published estimates of Eastern Population sandhill crane survival rate that can be used to inform harvest management. As part of two studies of Eastern Population sandhill crane migration, we deployed solar-powered global positioning system platform transmitting terminals on Eastern Population sandhill cranes ( n = 42) at key concentration areas from 2009 to 2012. We estimated an annual survival rate for Eastern Population sandhill cranes from data resulting from monitoring these cranes by using the known-fates model in the MARK program. Estimated annual survival rate for adult Eastern Population sandhill cranes was 0.950 (95% confidence interval = 0.885–0.979) during December 2009–August 2014. All fatalities ( n = 5) occurred after spring migration in late spring and early summer. We were unable to determine cause of death for crane fatalities in our study. Our survival rate estimate will be useful when combined with other population parameters such as the population index derived from the U.S. Fish and Wildlife Service fall survey, harvest, and recruitment rates to assess the effects of harvest on population size and trend and evaluate the effectiveness of management strategies.

Journal of Fish and Wildlife Management

Habitat selection by female northern pintails wintering in the Grassland Ecological Area, California

To determine relative importance of habitats available in the Grassland Ecological Area (GEA) to wintering female northern pintails, Anas acuta, we studied habitat use relative to availability (i.e., habitat selection) in the GEA during September through March, 1991-94 for 196 Hatch-Year (HY) and 221 After-Hatch-Year (AHY) female pintails that were radio tagged during August-early October in the GEA (n = 239), other San Joaquin Valley areas (n = 132), or other Central Valley areas (n = 46). Habitat availability and use varied among seasons and years, but pintails always selected shallow and, except on hunting days, open habitats. Swamp timothy, Heleochloa schoenoides, marsh was the most available, used, and selected habitat. Watergrass, Echinochloa crusgalli, marsh in the GEA was used less than available at night in contrast to previous studies in other SJV areas. Preferred late-winter habitats were apparently lacking in the GEA, at least relative to in the Sacramento Valley and Delta where most pintails moved to in December each year. Impacts on pintails of the increasing practice of managing marshes for increased emergent vegetation to attract other species should be monitored. Shallow, open habitats that produce seeds and invertebrates available to pintails in late winter would help maintain pintail abundance in the GEA.

California Fish and Game

Ecology and conservation of the Marbled Murrelet in North America: An overview

Over the past decade, the Marbled Murrelet has become a focus of much controversy. It was listed as threatened in Washington, Oregon, and California by the U.S. Fish and Wildlife Service in February 1993. In order to aid the various agencies with management, the Marbled Murrelet Conservation Assessment was formed to bring together scientists, managers, and others to gather all the available data on this small seabird. This volume of research is the culmination of that effort. In this chapter, we integrate the results of the investigations and summaries on the past history, present status, and possible future of the species, based on the data presented in this volume and other published research. We also propose what we consider the most important research needs. Then, based on the findings of this volume, we suggest actions for management to help ensure the survival of the species.

Book chapter

2005 annual progress report: Elk and bison grazing ecology in the Great Sand Dunes complex of lands

In 2000 the U.S. Congress authorized the expansion of the former Great Sand Dunes National Monument by establishing a new Great Sand Dunes National Park and Preserve in its place, and establishing the Baca National Wildlife Refuge. The establishment of Great Sand Dunes National Park and Preserve and the new Baca National Wildlife Refuge in the San Luis Valley (SLV), Colorado was one of the most significant land conservation actions in the western U.S. in recent years. The action was a result of cooperation between the National Park Service (NPS), U.S. Fish and Wildlife Service (USFWS), Bureau of Land Management (BLM), U.S. Forest Service (USDA-FS), and The Nature Conservancy (TNC). The new national park, when fully implemented, will consist of 107,265 acres, the new national preserve 41,872 acres, and the new national wildlife refuge (USFWS lands) 92,180 acres (fig. 1). The area encompassed by this designation protects a number of natural wonders and features including a unique ecosystem of natural sand dunes, the entire watershed of surface and groundwaters that are necessary to preserve and recharge the dunes and adjacent wetlands, a unique stunted forest, and other valuable riparian vegetation communities that support a host of associated wildlife and bird species. When the National Park was initially established, there were concerns about overconcentrations and impacts on native plant communities of the unhunted segments of a large and possibly growing elk (Cervus elaphus) population. This led to the designation of the Preserve as a compromise solution, where the elk could be harvested. The Preserve Unit, however, will not address all the ungulate management challenges. In order to reduce the current elk population, harvests of elk may need to be aggressive. But aggressive special hunts of elk to achieve population reductions can result in elk avoidance of certain areas or elk seeking refuge in areas where they cannot be hunted, while removals of whole herd segments and abandonment or alterations of migration routes can occur (Smith and Robbins, 1994; Boyce and others, 1991). Elk may seek refuge from hunting in the newly expanded Park Unit and TNC lands where they might overconcentrate and impact unique vegetation communities. In these sites of refugia, or preferred loafing sites, elk and bison could accelerate a decline in woody riparian shrubs and trees. This decline may also be due to changes in hydrology, climatic, or dunal processes, but ungulate herbivory might exacerbate the effects of those processes. To address the questions and needs of local resource managers, a multi-agency research project was initiated in 2005 to study the ecology, forage relations, and habitat relations of elk and bison in the Great Sand Dunes–Sangre de Cristo–Baca complex of lands. Meetings and discussions of what this research should include were started in 2001 with representatives from NPS, USFWS, TNC, the Colorado Division of Wildlife (CDOW), and USDA-FS/BLM. The final study plan was successfully funded in 2004 with research scheduled to start in 2005. The research was designed to encompass three major study elements: (1) animal movements and population dynamics, (2) vegetation and nutrient effects from ungulate herbivory, and (3) development of ecological models, using empirical data collected from the first two components, that will include estimates of elk carrying capacity and management scenarios for resource managers.

Colorado

Three decades of World Recreational Fishing Conferences: What have we learned about the dynamics of recreational fisheries?

Recreational fishing extends beyond catching fish, connecting individuals with nature, generating environmental stewards and contributing significantly to both local, regional and national economies. Assessing potential impacts on ecosystems and social-ecological systems requires dedicated multi- and interdisciplinary research and integrative management and policy approaches. Managing recreational fisheries effectively also necessitates transdisciplinary thinking, yet this poses continued challenges, as researchers and managers balance specialized expertise with innovative, boundary-crossing perspectives in light of limited funding in a rapidly changing social-ecological environment. The World Recreational Fishing Conference (WRFC) serves as the leading global scientific forum for addressing these challenges, fostering interdisciplinary exchange among scientists, managers, policy makers and stakeholders. The papers in this special issue represent the output of the last WRFC in Melbourne, Australia in 2023. By reviewing the content of the papers published in the present special issue, we illustrate the critical role of collaborative spaces, such as the WRFC, in bridging different expertise and approaches and fostering innovation, thereby securing adaptive management and conservation of recreational fisheries in response to global changes. Evaluating the development of the WRFC over three decades highlights how this conference series represents a leading think tank serving the entire network of recreational fisheries professionals globally.

Fisheries Management and Ecology

Foraging ecology as related to the distribution of planktivorous auklets in the Bering Sea

We review recent accounts of the foraging ecologies of five species of small auklets found in the Bering Sea. These birds eat a wide variety of zooplankton and micronekton. Least Auklets Aethia pusilla and Whiskered Auklets A. pygmaea , as far as is known, primarily eat copepods, whereas Created Auklets A. cristatella appear to specialize on euphausiids, at least during the breeding season. The diet of Parakeet Auklets Cyclorrhynchus psittacula is much broader than that of most other Aethia species, and includes many gelatinous species and their commensals. Little is known of the diet of Cassin's Auklet Ptychoramphus aleuticus in the Bering Sea, although elsewhere they take large copepods, euphausiids, and larval fish. There are considerable differences in the at-sea distributions and foraging behaviors of these five species of auklet. Least Auklets in the norhtern Bering Sea concentrate their foraging activities over strongly stratified water and near fronts where pycnoclines may approach the surface. In the Aleutian Islands, Least Auklets forage where oceanic and tidal currents strike the shelf between the islands and rise toward the surface carrying plankton. Least Auklets and Crested Auklets are often found in large flocks, whereas Parakeet Auklets are rarely found in groups of more than three birds and are usually widely dispersed. The few at-sea observations of Whiskered Auklets have been of small flocks in turbulent waters of island passes. We relate prey types taken, foraging dispersion, and the use of hydrographic features by these auklet species.

Conference Paper

Checklist of vertebrates of the United States, the U.S. territories, and Canada

On 30 January 1980 the Policy Group of the 1978 Interagency Agreement on Classifications and Inventory established a work group on fish and wildlife species names. The participating agencies were the Fish and Wildlife Service, Forest Service, Bureau of Land Management, Geological Survey, and Soil Conservation Service. The Fish and Wildlife Service was assigned the role of establishing and leading this work group in developing a national list of standard vertebrate species names that is up-to-date and accurate. The Association of Systematic Collections was contracted to develop the reference list. This publication is a revision of portions of the list (amphibians, reptiles, birds, and mammals), including updating to the end of 1985. The geographic areas encompassed by this list are: the United States, including Alaska and Hawaii; the Commonwealth of Puerto Rico, the U.S. Virgin Islands, and Navassa Island; the Trust Territory of the Pacific Islands (the Caroline Islands, Palau Islands, Marshall Islands, and northern Mariana Islands); and the U.S. Territories of American Samoa, Baker Island, Guam, Howland Island, Jarvis Island, the Johnston Islands, Kingman Reef, the Midway Islands, and Wake Islands. Canadian species that do not also occur in the United States have been included. This list includes the names of all Recent species known to occur, or to have occurred, in the geographic areas indicated above. No distinction is made between resident and migratory species or between those that occur regularly and those of casual or accidentally occurrence. The occurrence of all species listed is documented by specimen or photographic evidence. Zoo, aquarium, game park, and hunting preserve populations are not listed, nor are unestablished escapes from such populations. Species that are extinct are marked with a 1 . Species whose only occurrence in an area is the result of introduction by man are marked with a 2 . Species introduced into one area but native to another covered by this checklist do not have a superscript, nor do species for which the documentation of introduction is equivocal. Species listed as Endangered or Threatened (as of January 1987) throughout their ranges are marked with a 3 , whereas species with only selected subspecies or populations so listed are marked with a 4 . Refer to the Code of Federal Regulations (50 CFR) for further details on the Endangered Species Act of 1973 and its requirements. The list includes the scientific names and English names of taxa from order to species. At the level of genus and above, more than one English name may be given; this is to indicate content, not alternative names. English (common or vernacular) names for species vary from region to region and from author to author. The name "gopher", for example, has been applied to kinds of animals as diverse as pocket gophers, ground squirrels, and turtles. Most species have names in other languages as well as English names, and some species lack generally accepted English names. A single English name is given for each species in this list to promote uniformity and to permit more precise communication among users. Accurate communication about species can be assured only by using the scientific names, including their authors and date. We provide an "exploded" illustration (Fig. 1) of a typical portion of the list and identify the elements of each citation.

Resource Publication

Aerial strip-transect surveys: Indexing autumn–winter waterbird abundance and distribution in South Carolina

Aerial surveys integrating probability-based sample designs have been implemented successfully to estimate relative abundance of wintering ducks in Arkansas, Louisiana, Mississippi, and Missouri, but these approaches have not been evaluated in the Atlantic Flyway except for American black ducks ( Anas rubripes ) along the Atlantic coast. Furthermore, these surveys have not been used to index abundance of other nonbreeding waterbirds. Given elimination or reduction of resources allocated to the Midwinter Waterfowl Survey in the Atlantic Flyway and elsewhere, the South Carolina Department of Natural Resources (SCDNR) expressed a need for reliable surveys to monitor waterfowl and other waterbirds during autumn through winter. We designed stratified aerial strip-transect surveys to estimate population indices for migrating and wintering dabbling ducks (Anatini), diving ducks (Aythini, Mergini, Oxyurini), pelagic and piscivorous waterbirds (Anhingidae, Laridae, Pelicanidae, Phalacrocoracidae), and wading birds (Ardeidae, Ciconiidae, Threskiornithidae) in coastal and inland regions of South Carolina during autumn-winter 2017–2019. We used unequal probability random sampling to estimate population indices with deemed adequate precision (i.e., coefficient of variation [CV] ≤ 20%) and estimated theoretical survey efforts needed to achieve desired precision for future aerial surveys. Indices met our goal for precision in September and January 2018 for wading birds, in February and November 2018 for pelagic waterbirds, and in February 2018 for diving ducks, but never for other ducks during South Carolina waterfowl hunting season. We detected peak abundance of dabbling and diving ducks in January and wading birds and wood storks ( Mycteria americana ) in September. We estimated ~2.5 times greater survey effort was needed across waterbird taxa than was expended to achieve a CV=20%. We also used survey data to depict spatiotemporal variation in waterbird distributions across the study area. Our surveys are applicable for the SCDNR and other agencies seeking to monitor autumn-winter waterbird populations. Although survey refinements are necessary to increase precision in South Carolina, our waterbird indices are useful to assess population trends through time, guide habitat management and restoration efforts, refine local harvest regulations, inform law enforcement to detected illicit activities (e.g., baiting), and monitor possible shifting waterbird distributions in response to land-use and climate change.

South Carolina

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

Geographical 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.

The Journal of Wildlife Management

Premigrational movements and behavior of young mallards and wood ducks in north-central Minnesota

Movements and behavior of 89 young mallards (Anas platyrhynchos) and 48 young wood ducks (Aix sponsa) were monitored on a 932-km2 study area in north-central Minnesota in late summer and fall, 1972-74, with telemetry, visual observation, and aerial surveys. Initial flights of both species were confined to the natal (brood) marsh; first flights away from the natal marsh occurred in the third week after fledging in both species. First flights of young mallards and wood ducks away from their natal marshes were not significantly different between the sexes (mallard, mean = 4.95 km for females and 5.83 km for males; wood ducks, mean = 2.31 km for females and 2.64 km for males). However, flights away from the brood marshes by wood ducks were significantly shorter than for mallards.As young mallards and wood ducks grew, their daytime use of the natal marshes decreased in an irregular pattern as both species began daily flights between day- and night-use areas. Locally reared mallards made longer daily flights between use areas than did wood ducks, but wood ducks changed use areas with greater frequency before 1 October. Despite often extensive movements, most locally reared mallards and wood ducks remained in the vicinity of their brood marshes throughout fall until migration.Movement of young birds to new habitat was not the result of random searching and thus fortuitous discovery of nearby areas. Instead, birds seemed to learn of new habitat and develop movement patterns by associating with other birds; locally reared young always moved in the company of flocks of conspecifics that included adults and older immatures.Differences in movement patterns between the sexes of young birds and between young and adult birds cause them to be differentially distributed by age and sex on and near the breeding grounds. These differences are ultimately reflected in the distribution of the hunter harvest. We have interpreted generalizations about such phenomena, developed from analysis of continent-wide mallard banding data, using our data obtained from individually marked birds. We document (a) greater distances moved by early than by late-hatched young in the postbreeding period before migration, (b) differential movement of age and sex cohorts that explains greater hunting mortality of young than adults and of females than males near natal marshes, (c) differences in length and timing of postbreeding movements of adult male mallards and the postfledging movements of immature male mallards that help explain the northerly continental recovery distribution of young males, and (d) differential timing and rate of movement by birds through harvest areas (early departure of males and some return of females to natal marshes after the beginning of hunting) that explain differences in the timing of hunting season recoveries. Behavioral differences between the age and sex cohorts in the fall waterfowl population on and near their breeding grounds in north-central Minnesota can explain observed differences in survival and recovery rates of adult and young birds.The behaviors observed suggest to us that restrictive harvest regulations such as small-area closure may have little or no local benefits at the breeding grounds because premigratory assemblages of birds make extensive movements. In particular, protection of postbreeding adult females and locally reared young might only occur by closing large areas or scheduling extreme delays in the season opening, neither of which may be compatible with equitably apportioning waterfowl harvest at higher latitudes. Additional research on the local effects of restrictive regulations, and on age- and sex-specific differences in the timing, rate, and direction of fall movements of postbreeding waterfowl is needed.

Fish and Wildlife Research

Sora rail studies on the Patuxent River, Maryland

The freshwater marshes of the tidal Patuxent River are well known for their annual fall concentration of migrant soras ( Porzana carolina ) and were formerly the most famous rail hunting grounds in the Chesapeake Bay region. Because of concern over the apparent long-term decline in number of soras and the decline in the quality of the Patuxent marshes, especially the loss of wild rice ( Zizania aquatica ), the Maryland National-Capital Park and Planning Commission (MNCPPC), co-steward of the Jug Bay National Estuarine Research Reserve, sponsored rail-related research beginning in 1987. Past efforts focused on developing efficient trapping techniques, age and sex criteria, and monitoring body mass dynamics. Noted progress was made in developing digital playback systems and trap improvements to enhance sora captures. These improvements increased capture success by over an order of magnitude and resulted in capture of 2,315 soras and 276 Virginia rails ( Rallus limicola ) in the 5 year period, 1993-97. Although these methods demonstrate the efficacy of banding large numbers of soras on migration and possibly winter concentration areas, captures at the Patuxent River site have been 70-90% hatching-year birds and recoveries and recaptures have been virtually nonexistent. With the present effort, this outcome precludes population parameter estimation using traditional capture-recapture or recovery model methodologies. In 1996, studies were initiated to employ radio telemetry methods to investigate length of stay, habitat use, survival, and migration characteristics of fall migrant soras. These studies are ongoing and will be continued through 1998 with a grant from the U.S. Fish and Wildlife Service's Webless Migratory Game Bird Research Program and support from the U.S. Geological Survey's Patuxent Wildlife Research Center. Supplemental funding has also been provided by MNCPPC, FWS Region 5, the Maryland Ornithological Society, Quail Unlimited, and Prince Georges Community College. During 1996-97 we developed a successful radio transmitter attachment technique to secure 1.8g radio transmitters over the synsacrum of migrant soras. We modified Rappole and Tipton's (1991) leg-loop attachment method by addition of a waist loop to prevent soras from slipping transmitters over their short tails. Thin gauge (0.6 mm) elastic thread proved ideal for attachment and allowed for girth expansion associated with fattening during stopover. Sixty instrumented soras have been monitored in two years of study from early September until early November. Only a single mortality was recorded and 41 (68%) were confIrmed and another 13 (total 90%) were believed to have migrated from the study area. Only a single bird slipped a radio transmitter. Most birds demonstrated a sedentary nature in the marsh throughout stopover. Average length of stay was 44 days in 1997 (n=29) with peak departure occurring 20-24 October. Departing migrants were detected using a receiver/data-logger monitoring system placed 4 miles down river from the study site. Thirty-six of 37 (97%) soras departed in a 2-hour window of time, beginning 1 hour after sunset. Departure was synchronized with cold fronts on clear, starlit nights. Twenty-five soras were monitored on migration from 8 km to as far away as 770 km. Findings indicate migration flight speeds of 40 to 50 mph and a direct southward orientation from the study site at least until contact with the Atlantic Ocean west of Cape Lookout, North Carolina. We also attempted to monitor passage of migrant soras radio tagged at Iroquois National Wildlife Refuge in western New York by biologist Soch Lor. None were recorded passing a monitoring unit at Haldeman Island in the middle of the Susquehanna River 10 miles north of Harrisburg, Pennsylvania. This further corroborates our findings that when migrating overland, soras move in a direct southward orientation and are not following land features such as major rivers

Book chapter

Protocol and practice in the adaptive management of waterfowl harvests

Waterfowl harvest management in North America, for all its success, historically has had several shortcomings, including a lack of well-defined objectives, a failure to account for uncertain management outcomes, and inefficient use of harvest regulations to understand the effects of management. To address these and other concerns, the U.S. Fish and Wildlife Service began implementation of adaptive harvest management in 1995. Harvest policies are now developed using a Markov decision process in which there is an explicit accounting for uncontrolled environmental variation, partial controllability of harvest, and structural uncertainty in waterfowl population dynamics. Current policies are passively adaptive, in the sense that any reduction in structural uncertainty is an unplanned by-product of the regulatory process. A generalization of the Markov decision process permits the calculation of optimal actively adaptive policies, but it is not yet clear how state-specific harvest actions differ between passive and active approaches. The Markov decision process also provides managers the ability to explore optimal levels of aggregation or "management scale" for regulating harvests in a system that exhibits high temporal, spatial, and organizational variability. Progress in institutionalizing adaptive harvest management has been remarkable, but some managers still perceive the process as a panacea, while failing to appreciate the challenges presented by this more explicit and methodical approach to harvest regulation. Technical hurdles include the need to develop better linkages between population processes and the dynamics of landscapes, and to model the dynamics of structural uncertainty in a more comprehensive fashion. From an institutional perspective, agreement on how to value and allocate harvests continues to be elusive, and there is some evidence that waterfowl managers have overestimated the importance of achievement-oriented factors in setting hunting regulations. Indeed, it is these unresolved value judgements, and the lack of an effective structure for organizing debate, that present the greatest threat to adaptive harvest management as a viable means for coping with management uncertainty. Copyright ?? 1999 by The Resilience Alliance.

Conservation Ecology