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At least 469 records · Page 26Linked to original sources

A review of the population estimation approach of the North American landbird conservation plan

As part of their development of a continental plan for monitoring landbirds (Rich et al. 2004), Partners in Flight (PIF) applied a new method to make preliminary estimates of population size for all 448 species of landbirds present in the continental United States and Canada (Table 1). Estimation of the global population size of North American landbirds was intended to (1) identify the degree of vulnerability of each species, (2) provide estimates of the current population size for each species, and (3) provide a starting point for estimating population sizes in states, provinces, territories, and Bird Conservation Regions (Rich et al. 2004). A method proposed by Rosenberg and Blancher (2005) was used to derive population estimates from available survey data. To enhance the credibility of these estimates, PIF organized a review of the methodology used to estimate North American landbird population sizes. A planning committee selected members from the ornithological and biometrical communities (hereafter “the panel”), with the aim of selecting individuals from academia, state natural-resource agencies, and the U.S. and Canadian federal governments, including the Canadian Wildlife Service, the U.S. Geological Survey, and the U.S. Department of Agriculture Forest Service. The panel addressed three questions: (1) Were the methods of population estimation proposed by PIF reasonable? (2) What actions could be taken to improve the data or analyses on which the PIF population estimates were based? and (3) How should the PIF population estimates be interpreted?

The Auk↗

Circumpolar variation in morphological characteristics of Greater White-fronted Geese Anser albifrons

Capsule: Greater White-fronted Geese show significant variation in body size from sampling locations throughout their circumpolar breeding range. Aims: To determine the degree of geographical variation in body size of Greater White-fronted Geese and identify factors contributing to any apparent patterns in variation. Methods: Structural measures of >3000 geese from 16 breeding areas throughout the Holarctic breeding range of the species were compared statistically. Results: Palearctic forms varied clinally, and increased in size from the smallest forms on the Kanin and Taimyr peninsulas in western Eurasia to the largest forms breeding in the Anadyr Lowlands of eastern Chukotka. Clinal variation was less apparent in the Nearctic, as both the smallest form in the Nearctic and the largest form overall (the Tule Goose) were from different breeding areas in Alaska. The Tule Goose was 25% larger than the smallest form. Birds from Greenland (A. a. flavirostris) were the second largest, although only slightly larger than geese from several North American populations. Body size was not correlated with breeding latitude but was positively correlated with temperature on the breeding grounds, breeding habitat, and migration distance. Body mass of Greater White-fronted Geese from all populations remained relatively constant during the period of wing moult. Morphological distinctness of eastern and western Palearctic forms concurs with earlier findings of complete range disjunction. Conclusions: Patterns of morphological variation in Greater White-fronted Geese across the Holarctic can be generally attributed to adaptation to variable breeding environments, migration requirements, and phylo-geographical histories.

Bird Study↗

The dynamics of avian influenza in western Arctic snow geese: implications for annual and migratory infection patterns

Wild water birds are the natural reservoir for low-pathogenic avian influenza viruses (AIV). However, our ability to investigate the epizootiology of AIV in these migratory populations is challenging, and despite intensive worldwide surveillance, remains poorly understood. We conducted a cross-sectional, retrospective analysis in Pacific Flyway lesser snow geese Chen caerulescens to investigate AIV serology and infection patterns. We collected nearly 3,000 sera samples from snow geese at 2 breeding colonies in Russia and Canada during 1993-1996 and swab samples from > 4,000 birds at wintering and migration areas in the United States during 2006-2011. We found seroprevalence and annual seroconversion varied considerably among years. Seroconversion and infection rates also differed between snow goose breeding colonies and wintering areas, suggesting that AIV exposure in this gregarious waterfowl species is likely occurring during several phases (migration, wintering and potentially breeding areas) of the annual cycle. We estimated AIV antibody persistence was longer (14 months) in female geese compared to males (6 months). This relatively long period of AIV antibody persistence suggests that subtype-specific serology may be an effective tool for detection of exposure to subtypes associated with highly-pathogenic AIV. Our study provides further evidence of high seroprevalence in Arctic goose populations, and estimates of annual AIV seroconversion and antibody persistence for North American waterfowl. We suggest future AIV studies include serology to help elucidate the epizootiological dynamics of AIV in wild bird populations.

Ecological Applications↗

Grassland bird associations with introduced and native grass Conservation Reserve Program fields in the Southern High Plains

We examined relative abundances of grassland birds among Conservation Reserve Program (CRP) fields seeded with 2 monocultures of introduced grass species and 2 mixes of native grasses in the Southern High Plains of Texas. We assessed bird compositions among these 4 cover types and between the cover types pooled into categories of introduced and native fields. Breeding season bird diversity and total abundance did not differ among cover types or between introduced and native fields. Grasshopper Sparrows ( Ammodramus savannarum ), Cassin's Sparrows ( Aimophila cassinii ), and Western Meadowlarks ( Sturnella neglecta ) accounted for more than 90% of breeding season detections. Grasshopper Sparrows were the most abundant and found in all cover types. Cassin's Sparrows were 38% to 170% more abundant among the native seed mix without buffalograss ( Buchloë dactyloides ) compared to 3 other cover types. Although this association was statistically lost when cover types were pooled into introduced or native fields ( U = 93.5, P = 0.91), the species was still 50% more abundant among native CRP than introduced CRP fields. Meadowlarks occurred ubiquitously but at very low numbers during the breeding season. During winter, avian abundance was 44% greater among native CRP than introduced CRP fields. Meadowlarks, Homed Larks ( Eremophila alpestris ), and Savannah Sparrows ( Passerculus sandwichensis ) accounted for 94% of all winter detections. Meadowlarks occurred ubiquitously, but Horned Larks and Savannah Sparrows were 157% and 96% more abundant, respectively, among native CRP than introduced CRP fields. Our data suggest that monocultures of introduced grasses may benefit some bird species but also that native seed mixes may have a more positive influence through increased diversity and abundance of grassland birds. However, pooling cover types into the broader categories of introduced or native grasses may dampen or occlude biologically meaningful results. It may be prudent to avoid broad categorization of CRP fields based solely on native or introduced grass cover when assessing habitat associations of grassland birds.

Texas↗

The short-tailed Albatross, Diomedea albatrus , its status, distribution and natural history

The Short-tailed Albatross (Diomedea albatrus ) is presently an Endangered Species that was formerly abundant in the North Pacific. Owing to the activities of feather hunters operating on the albatross's nesting grounds for a 50-year period in the late 19th and early 20th centuries, the species was almost reduced to extinction. The Short-tailed Albatross is the largest of the three species of Diomedea that breed in the North Pacific (Table 1) and when mature is the only albatross in the North Pacific with a white back .

American Birds↗

Left out in the rain: Comparing productivity of two associated species exposes a leak in the umbrella species concept

Multi-species approaches to wildlife management have become commonplace and purport to benefit entire biological communities. These strategies aim to manage different, often taxonomically distant species under a single regime based on shared habitat associations and/or co-occurrence in the landscape. We tested the efficacy of multi-species management in the context of creating and maintaining early-successional forest cover types using two species of migratory birds that breed in eastern North America and are each the focus of intensive, concurrent, and overlapping management. American woodcock ( Scolopax minor ) and golden-winged warblers ( Vermivora chrysoptera ) breed in similar diverse-forest landscapes. Each species purportedly benefits from management for the other species and both are often used as flagship species for the creation of young forest and the conservation of associated avian communities. However, the landscape-species relationships that drive reproductive success and population stability in these species have not been explicitly compared. Here, we use previously published spatially-explicit models of productivity (the number of juveniles raised to a biologically significant milestone) to identify the relationship(s) between productivity of American woodcock and golden-winged warblers across a shared landscape. We found productivity to be negatively associated between these species on the same landscape at all spatial scales we modelled (1 m 2 –100 ha). Our results suggest that, with regards to productivity, American woodcock and golden-winged warblers have opposing relationships with the composition of the landscapes in which they coexist and therefore should not be assumed to benefit similarly from any individual management action at any relevant spatial scale.

Biological Conservation↗

The distribution and conservation status of the Gull-billed Tern (Gelochelidon nilotica) in North America

The Gull-billed Tern (Gelochelidon nilotica) has until recently received little conservation and management attention within North America despite a relatively low overall population size and significant declines in parts of the breeding range. This lack of attention may stem in part from the wide distribution of the species, encompassing parts of six continents, and from its tendency to nest in relatively small, scattered and often ephemeral colonies. Populations of North American subspecies are alarmingly small. The current population of the eastern subspecies aranea in the U.S. is unlikely to exceed 3,600 pairs, with over 60% of these birds occurring in Texas. The Texas population has remained generally stable, but declines of populations in Maryland (where probably extirpated), Virginia, North Carolina, Florida, and possibly Georgia give cause for concern for this subspecies. For the western subspecies vanrossemi, as few as 250 pairs nest at only two locations in the U.S., both in California. When populations in western Mexico are considered, the entire vanrossemi population numbers only 600-800 pairs. Currently the Gull-billed Tern is listed as ?endangered? or ?threatened? in four states, and is considered to be of management concern in five others. The breeding range of the species has contracted and shifted slightly from its known historic range in the middle Atlantic states, but otherwise occupies its historic range in the United States and has expanded slightly to coastal southern California. Some range contraction in Mexico (e.g., in Sonora) may have occurred. In eastern Mexico, historical information is almost non-existent and knowledge of current distribution and abundance is incomplete. Main threats to populations in North America include loss of natural nesting islands through beach erosion or perturbations to estuarine functions, development or modification of upland habitats near breeding areas that may be important for foraging, and disturbances to colonies by humans and feral or human-subsidized predators. This species often nests on man-made substrates suggesting it could be responsive to management of breeding sites. Key research needs include more frequent and refined population monitoring, a better understanding of demographics, metapopulation dynamics and factors limiting populations as well as refinement of subspecies? breeding distributions and wintering ranges.

Waterbirds↗

The persistent problem of lead poisoning in birds from ammunition and fishing tackle

Lead (Pb) is a metabolic poison that can negatively influence biological processes, leading to illness and mortality across a large spectrum of North American avifauna (>120 species) and other organisms. Pb poisoning can result from numerous sources, including ingestion of bullet fragments and shot pellets left in animal carcasses, spent ammunition left in the field, lost fishing tackle, Pb-based paints, large-scale mining, and Pb smelting activities. Although Pb shot has been banned for waterfowl hunting in the United States (since 1991) and Canada (since 1999), Pb exposure remains a problem for many avian species. Despite a large body of scientific literature on exposure to Pb and its toxicological effects on birds, controversy still exists regarding its impacts at a population level. We explore these issues and highlight areas in need of investigation: (1) variation in sensitivity to Pb exposure among bird species; (2) spatial extent and sources of Pb contamination in habitats in relation to bird exposure in those same locations; and (3) interactions between avian Pb exposure and other landscape-level stressors that synergistically affect bird demography. We explore multiple paths taken to reduce Pb exposure in birds that (1) recognize common ground among a range of affected interests; (2) have been applied at local to national scales; and (3) engage governmental agencies, interest groups, and professional societies to communicate the impacts of Pb ammunition and fishing tackle, and to describe approaches for reducing their availability to birds. As they have in previous times, users of fish and wildlife will play a key role in resolving the Pb poisoning issue.

The Condor↗

Sapsucker wells as a keystone nutritional resource: Evaluating methods for detection of secondary sap consumers

North American sapsuckers are considered double keystone species because they (1) excavate nest cavities that are used by other birds, small mammals, and invertebrates, and (2) create and maintain sap wells, a temporary nutritional resource available to a variety of secondary consumers. Most previous reports of secondary sap consumption relied on human observers and were based on either brief or incidental observations. However, modern technology can greatly enhance observational techniques and provide additional insights into the functional, community-level importance of sap wells. We used visual surveys, camera traps, and environmental DNA (eDNA) to identify secondary consumers of sap from wells created by red-naped ( Sphyrapicus nuchalis ) and Williamson's ( S. thyroideus ) sapsuckers among three functional groups of shrubs and trees in south-central Colorado: shrub willows ( Salix spp.), Rocky Mountain maple ( Acer glabrum ), and conifer trees (Pinopsida). Camera traps and eDNA revealed additional sap-well visitors not identified from direct observations. Camera traps were effective for detecting nocturnal sap-well visitors such as small rodents as well as occasional diurnal visitors. Environmental DNA analyses corroborated findings from other methods and identified four additional taxa as possible sap consumers. The physiology of sap-well visitors, such as the ability to taste and assimilate compounds within sap, may aid in determining consumption versus contact when evaluating the results of eDNA analyses. Total vertebrate taxa detected using all 3 methods included 17 bird taxa in 10 families within 3 orders and 8 mammal taxa in 6 families within 4 orders. Shrub-willow sap wells attracted the most diverse vertebrate taxa (23), followed by Rocky Mountain maple (13) and conifer trees (10). Invertebrates in 13 families within 3 orders were observed feeding from sap wells during visual surveys. Because many secondary sap consumers perform ecological services such as pollination, seed dispersal, and pest control, the methods described here may aid in elucidating the importance of sap-well creators in supporting biodiversity and ecosystem functioning.

Colorado↗

The spring migration of adult North American Ospreys

Most North American Ospreys ( Pandion haliaetus ) are migratory, breeding in northern latitudes and migrating long distances to and from their wintering grounds in the tropics. Although fall migration patterns of North American Ospreys have been described and studied, very little has been published about the spring migration of these birds. We used satellite telemetry to: (1) determine the characteristics (timing, duration, migratory routes) of spring migrations of Ospreys; (2) determine if differences in spring migration patterns existed between sexes and among three breeding populations (east coast, midwestern, and western); and (3) compare consecutive fall and spring migrations of individual Ospreys. The median dates for departure from the wintering grounds and arrival on the breeding grounds did not differ significantly between adult male and female Ospreys. Compared to their fall migrations, all male and all east coast Ospreys spent fewer days on migration, fewer days in stopover periods along the migration route, traveled shorter distances overall, and traveled farther (on average) each day during spring. In contrast, fall and spring migration characteristics of all female and western Ospreys were similar. Our findings suggest that, although sex and breeding location might influence the spring migration strategy used by individual Ospreys, both males and females minimize the time spent on migration to ensure a timely arrival on the breeding grounds to establish or defend a nesting territory.

Journal of Raptor Research↗

The American Oystercatcher ( Haematopus palliatus ) Working Group: 15 years of collaborative focal species research and management

The American Oystercatcher ( Haematopus palliatus ) Working Group formed spontaneously in 2001 as coastal waterbird biologists recognized the potential for American Oystercatchers to serve as focal species for collaborative research and management. Accomplishments over the past 15 years include the establishment of rangewide surveys, color-banding protocols, mark-resight studies, a revision of the Birds of North America species account, and new mechanisms for sharing ideas and data. Collaborations among State, Federal, and private sector scientists, natural resource managers, and dedicated volunteers have provided insights into the biology and conservation of American Oystercatchers in the United States and abroad that would not have been possible without the relationships formed through the Working Group. These accomplishments illustrate how broad collaborative approaches and the engagement of the public are key elements of effective shorebird conservation programs.

Waterbirds↗

Habitat suitability index models: redhead (wintering)

The redhead is a North American waterfowl species with economic as well as ecological importance. It is highly desired by hunters. Retrieved redhead kill in the United States averaged 143,000 birds during the three waterfowl seasons from 1975 to 1977 (U.S. Department of the Interior 1981a, 1981b). Populations on the principal breeding grounds of the redhead--the prairie and parkland region of south-central Canada and north-central United States--averaged 710,000 birds from 1955 to 1981 (Bellrose 1976; A. Novara, U.S. Fish and Wildlife Service [USFWS], Jamestown, North Dakota; pers. comm.). Redhead numbers began to decline in the 1960's. Killing redheads became illegal from 1960 to 1963, and strict bag limits were imposed after that (Bellrose 1976). A breeding population low of 387,000 birds occurred in 1963, but prairie populations began to recover after that time. Their numbers peaked in 1980 when 1,146,000 birds were recorded (A. Novara, pers. comm.). During the fall, over a third of the total redhead population uses the migration corridor that extends from the prairie breeding area to the Texas gulf coast. Another migration corridor extends from the second most important breeding area--the Great Salt Basin--to the Texas coast (Bellrose 1976). During the fall, over a third of the total redhead population uses the migration corridor that extends from the prairie breeding area to the Texas gulf coast. Another migration corridor extends from the second most important breeding area--the Great Salt Basin--to the Texas coast (Bellrose 1976).

FWS/OBS↗

Grassland Effectiveness Monitoring (GEM): A tiered approach for habitat treatment assessment across private lands incentive programs

Introduction The decline of North American grasslands is a topic of increasing interest as agencies and organizations work to address subsequent declines in wildlife species, including grassland birds (Rosenberg et al. 2019), pronghorn (Antilocapra americana) (Gedir et al. 2015), and other grassland-dependent taxa. In response to grassland habitat loss, conservation programs and policies have been developed to provide biologists and landowners mechanisms to restore grassland habitat on private lands. These range from federal programs such as the U.S. Fish and Wildlife Service’s (USFWS) Partners for Fish and Wildlife program (PFW) and the Natural Resources Conservation Service’s (NRCS) Environmental Quality Incentive Program, state programs such as Texas Parks and Wildlife Department’s Pastures for Upland Birds, and partnership-based programs such as the Oaks and Prairies Joint Venture’s Grassland Restoration Incentive Program (GRIP). When managing and restoring grassland habitat, these programs typically utilize the same set of practices: prescribed grazing, prescribed fire, herbicide, brush management, and range planting. To restore grasslands at scale, large sums of funding have been invested into these programs. For example, approximately $1 million is spent by PFW in Texas annually (D. Wilhelm, USFWS, personal communication). However, it is rare for these conservation programs to have associated monitoring efforts that are consistently used to assess the effectiveness of the aforementioned practices in achieving program and project objectives. As such, it is difficult to communicate to funders and the public whether these conservation programs are successfully addressing grassland decline. Similar objectives and practices across programs, however, provide a unique opportunity for developing an innovative monitoring methodology that focuses on providing a collaborative solution to this dilemma. Our objective is to develop a grassland monitoring program that can be used across agencies, organizations, and conservation programs to assess the effectiveness of practices and programs in restoring healthy grasslands. In addition, we seek to develop a program that maintains consistency to allow for regional to national-scale reporting while also allowing flexibility for achieving local and partner monitoring objectives. Our vision is for this program to be used across North American grasslands to improve our ability to address the questions: “Is it actually working?” and “How can we improve habitat delivery?”

Conference Paper↗

Avian influenza at both ends of a migratory flyway: characterizing viral genomic diversity to optimize surveillance plans for North America

Although continental populations of avian influenza viruses are genetically distinct, transcontinental reassortment in low pathogenic avian influenza (LPAI) viruses has been detected in migratory birds. Thus, genomic analyses of LPAI viruses could serve as an approach to prioritize species and regions targeted by North American surveillance activities for foreign origin highly pathogenic avian influenza (HPAI). To assess the applicability of this approach, we conducted a phylogenetic and population genetic analysis of 68 viral genomes isolated from the northern pintail (Anas acuta) at opposite ends of the Pacific migratory flyway in North America. We found limited evidence for Asian LPAI lineages on wintering areas used by northern pintails in California in contrast to a higher frequency on breeding locales of Alaska. Our results indicate that the number of Asian LPAI lineages observed in Alaskan northern pintails, and the nucleotide composition of LPAI lineages, is not maintained through fall migration. Accordingly, our data indicate that surveillance of Pacific Flyway northern pintails to detect foreign avian influenza viruses would be most effective in Alaska. North American surveillance plans could be optimized through an analysis of LPAI genomics from species that demonstrate evolutionary linkages with European or Asian lineages and in regions that have overlapping migratory flyways with areas of HPAI outbreaks.

Alaska, California↗

Feeding ecology of long-tailed ducks Clangula hyemalis wintering on the Nantucket Shoals

A substantial proportion, perhaps 30%, of the North American breeding population of Long-tailed Ducks ( Clangula hyemalis ) winter in the vicinity of Nantucket Island, Massachusetts. These birds spend the night on Nantucket Sound and commute during daylight hours to the Nantucket Shoals, which extend about 65 km offshore from the southeastern corner of Nantucket. Strip transects done from a single-engine plane in 1997 and 1998 indicated that Long-tailed Ducks foraged over the shallower (≤ 20 m depth) portions of the Nantucket Shoals, up to 70 km offshore. Diet analyses of ten birds collected in February 1999 and five in December 2006 showed that they fed principally (106.6 /- 42.0 individuals per crop) on Gammarus annulatus , a pelagic amphipod that often forms large aggregations, and is consumed by several species of fish and marine mammals. Our findings emphasize the importance of conservation of the Nantucket Shoals and the prevention of oil spills or other potentially harmful accidents.

Massachusetts↗

Prevalence of West Nile virus in migratory birds during spring and fall migration

To investigate the role of migratory birds in the dissemination of West Nile virus (WNV), we measured the prevalence of infectious WNV and specific WNV neutralizing antibodies in birds, principally Passeriformes, during spring and fall migrations in the Atlantic and Mississippi flyways from 2001-2003. Blood samples were obtained from 13,403 birds, representing 133 species. Specific WNV neutralizing antibody was detected in 254 resident and migratory birds, representing 39 species, and was most commonly detected in northern cardinals (Cardinalis cardinalis) (9.8%, N = 762) and gray catbirds (Dumetella carolinensis) (3.2%,N = 3188). West Nile virus viremias were detected in 19 birds, including 8 gray catbirds, and only during the fall migratory period. These results provide additional evidence that migratory birds may have been a principal agent for the spread of WNV in North America and provide data on the occurrence of WNV in a variety of bird species. Copyright ?? 2009 by The American Society of Tropical Medicine and Hygiene.

American Journal of Tropical Medicine and Hygiene↗

Shorebirds: East of the 105th meridian

The North American group of shorebirds includes 48 kinds of sandpipers, plovers, and their allies, many of which live for most of the year in coastal marine habitats; other live principally in nonmarine habitats including grasslands, freshwater wetlands, and even second-growth woodlands. Most North American shorebirds are highly migratory, while others are weakly migratory, and even nonmigratory in some parts of their range. Here we discuss shorebirds east of the 105th meridian (roughly east of the Rocky Mountains). Historically, populations of many North American species were dramatically reduces by excessive gunning (Forbush 1912). Most populations recovered after the passage of the Migratory Bird Treaty Act of 1918, although some species never recovered and others have declined again. High proportions of entire populations of shorebirds migrate by visiting one or a small number of "staging sites", areas where the birds accumulate fat to provide fuel before continuing with their long-distance, nonstop flights to the next site (Morrison and Harrington 1979; Senner and Howe 1984; Harrington et al. 1991). Growing evidence (Schneider and Harrington 1981) indicates that staging areas are unusually productive sites with highly predictable but seasonally ephemeral "blooms" of invertebrates, which shorebirds use for fattening. In some cases, especially for "obligate" coastal species, specific sites are traditionally used; even other species sites may shift between years. Because pf this, conservationists believe some species are at risk through loss of strategic migration site (Myers et al. 1987). Other species are threatened by the less of breeding and wintering habitats (Page et al. 1991; Haig and Plissner 1993; B. Leachman and B. Osmundsom, U.S. Fish and Wildlife Service, unpublished data). The predicted consequences of global warming, such as sea-level change, will also strongly affect the intertidal marine habitats, which many species of shorebirds depend upon. Some of the strongest warming effects will be at high latitudes, including those where many shorebirds migrate to breed, as well as south temperate latitudes, where many of them winter.

Book chapter↗

Wildlife values of North American ricelands

Ricelands have become an indispensable component of waterbird habitat and a leading example of integrating agricultural and natural resource management in the Mississippi Alluvial Valley, Gulf Coast, and Central California. Residual rice, weed seeds, and invertebrates provide food for many avian species during fall and winter. In North America, considerable information exists on the use of ricefields by wintering waterbirds, the value of ricelands as breeding habitat for birds, and the effects of organic chemicals on birds that- feed in ricefields. Recent research has also examined the influence of field management practices, such as winter flooding and post-harvest straw manipulation, on the suitability of ricefields for wildlife. Whereas early studies focused on detrimental effects of wildlife on rice production (e.g., crop depredation), it has become apparent that waterbirds may benefit producers by enhancing straw decomposition, reducing weed and pest pressure, and providing additional income through hunting and wildlife viewing opportunities. A comprehensive evaluation of agronomic and environmental issues is needed to meet the challenges of producing food and sustaining wildlife in twenty-first-century rice lands. Changes in agricultural markets, pressures of increased urban development, conflicting needs for limited resources such as water, endangered species constraints, and concerns over water quality must be addressed in developing a sustainable, mutually beneficial partnership among the rice industry, wildlife, and environmental interests. Research is also needed to evaluate potential reductions in the wildlife carrying capacity of ricelands resulting from new harvest and field management techniques, crop conversion, or loss of rice acreage. Key uncertainties include: (1) changes in waste grain abundance and availability due to various harvest and post-harvest management practices; (2) evaluating food depletion by birds feeding in rice6elds and derermining threshold food levels required to maintain bird use; (3) quantifying use of ricefields by nonwaterfowl species throughout the year; and (4) determining the amount and distribution of rice habitat needed to meet objectives of the North American Waterfowl Management Plan and the United States Shorebird Conservation Plan.

Book chapter↗