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At least 73 records · Page 4Linked to original sources
USGS2013

Genetic diversity and mutation of avian paramyxovirus serotype 1 (Newcastle disease virus) in wild birds and evidence for intercontinental spread

Avian paramyxovirus serotype 1 (APMV-1), or Newcastle disease virus, is the causative agent of Newcastle disease, one of the most economically important diseases for poultry production worldwide and a cause of periodic epizootics in wild birds in North America. In this study, we examined the genetic diversity of APMV-1 isolated from migratory birds sampled in Alaska, Japan, and Russia and assessed the evidence for intercontinental virus spread using phylogenetic methods. Additionally, we predicted viral virulence using deduced amino acid residues for the fusion protein cleavage site and estimated mutation rates for the fusion gene of class I and class II migratory bird isolates. All 73 isolates sequenced as part of this study were most closely related to virus genotypes previously reported for wild birds; however, five class II genotype I isolates formed a monophyletic clade exhibiting previously unreported genetic diversity, which met criteria for the designation of a new sub-genotype. Phylogenetic analysis of wild-bird isolates provided evidence for intercontinental virus spread, specifically viral lineages of APMV-1 class II genotype I sub-genotypes Ib and Ic. This result supports migratory bird movement as a possible mechanism for the redistribution of APMV-1. None of the predicted deduced amino acid motifs for the fusion protein cleavage site of APMV-1 strains isolated from migratory birds in Alaska, Japan, and Russia were consistent with those of previously identified virulent viruses. These data therefore provide no support for these strains contributing to the emergence of avian pathogens. The estimated mutation rates for fusion genes of class I and class II wild-bird isolates were faster than those reported previously for non-virulent APMV-1 strains. Collectively, these findings provide new insight into the diversity, spread, and evolution of APMV-1 in wild birds.

Archives of Virology↗
USGS2016

Antigenic characterization of H3 subtypes of avian influenza A viruses from North America

Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

Avian Diseases↗
USGS2006

Patch size and landscape effects on density and nesting success of grassland birds

Current management recommendations for grassland birds in North America emphasize providing large patches of grassland habitat within landscapes that have few forest or shrubland areas. These Bird Conservation Areas are being proposed under the assumption that large patches of habitat in treeless landscapes will maintain viable populations of grassland birds. This assumption requires that patch size and landscape features affect density and nesting success of grassland birds, and that these effects are consistent among years and regions and across focal species. However, these assumptions have not yet been validated for grassland birds, and the relative importance of local vegetation structure, patch size, and landscape composition on grassland bird populations is not well known. In addition, factors influencing grassland bird nesting success have been investigated mostly in small-scale and short-duration studies. To develop management guidelines for grassland birds, we tested the spatial and temporal repeatability of the influence of patch size and landscape composition on density and nesting success of 3 grassland passerines, after controlling for local-scale vegetation structure, climate, and—when analyzing nest success—bird density. We conducted our study during 4 years (1998–2001) in 44 study plots that were set up in 3 regions of the northern tallgrass prairie in Minnesota and North Dakota, USA. In these study plots we measured density and nesting success of clay-colored sparrows ( Spizella pallida ), Savannah sparrows ( Passerculus sandwichensis ), and bobolinks ( Dolichonyx oryzivorus ). Statistical models indicated that density was influenced by patch size, landscape, region, and local vegetation structure more so than by local vegetation structure alone. Both magnitude and direction of the response of density to patch size varied among regions, years, and species. In contrast, the direction of landscape effects was consistent among regions, years, and between Savannah sparrows and bobolinks. In each species, this landscape effect was independent of patch size. Nesting success was not clearly influenced by patch size or landscape composition, and none of the factors that influenced avian density also influenced nesting success in any of the 3 species. General statements on “optimal habitat” for grassland birds should therefore be viewed cautiously. Instead, long-term studies in different regions as well as a deeper understanding of the local system are needed to determine which factors are most important for grassland birds in a particular area.

Journal of Wildlife Management↗
USGS2006

Migratory connectivity of a widely distributed songbird, the American redstart (Setophaga ruticilla)

Determining the degree of connectivity between breeding and wintering populations is critical for understanding the ecology and evolution of migratory systems. We analyzed stable hydrogen isotopic compositions in tail feathers ($Dw) collected from 26 sites in 11 countries throughout the wintering range of the American Redstart (Setophaga ruticilla), a Nearctic- Neotropical migratory passerine bird. Feathers were assumed to have molted on the breeding grounds, and $Dw was used to estimate breeding origin. Values of $Dw were highly correlated with longitude of sampling location, indicating that breeding populations were generally distributed along the east-west axis of the wintering grounds. Within the Caribbean region, Florida, and Bahamas, $Dw values were negatively correlated with winter latitude, which suggests that American Redstarts exhibit a pattern of chain migration in which individuals wintering at northern latitudes are also the most northern breeders. To identify the most probable breeding regions, we used a likelihood-assignment test incorporated with a prior probability of breeding abundance using Bayes?s rule. Expected $D values of feathers from five breeding regions were based on interpolated $D values from a model of continent-wide growing-season $D values in precipitation ($Dp) and were adjusted to account for a discrimination factor between precipitation and feathers. At most wintering locations, breeding assignments were significantly different from expected frequencies based on relative breeding abundance. Birds wintering in eastern and western Mexico had a high probability of breeding in northwest and midwest North America, whereas birds in the Greater and Lesser Antilles were likely to have originated from breeding regions in the northeast and southeast, respectively. Migratory connectivity, such as we report here, implies that the dynamics of breeding and nonbreeding populations may be linked at a regional scale. These results provide a key opportunity for studying the year-round ecology and evolution of spatially connected populations in a migratory species.

Book chapter↗
USGS2025

Observational, virological, and serological data provide insights into an outbreak of highly pathogenic avian influenza among wild birds on the Yukon-Kuskokwim Delta, Alaska in 2022

In 2021–22, clade 2.3.4.4b highly pathogenic avian influenza (HPAI) viruses were introduced by wild birds into North America, leading to geographically widespread disease. In response to HPAI outbreaks throughout late 2021 and early 2022, we recorded observations of sick and dead birds, estimated abundance of carcasses, collected swab and sera samples to detect viruses, and monitored bird nesting on the Yukon-Kuskokwim Delta region of Alaska to document potential effects of disease. Thirty-six reports of sick and dead birds were registered across the region. Nineteen carcasses were opportunistically collected for diagnostic testing, of which 12 were confirmed to be infected with clade 2.3.4.4b HPAI viruses. Carcass abundance estimates from line-distance sampling provided evidence that the most common species of dead birds from the western Yukon-Kuskokwim Delta region were Cackling Goose ( Branta hutchinsii minima ), Glaucous Gull ( Larus hyperboreus ), and Black Brant ( Branta bernicla nigricans ). Only one paired cloacal and oropharyngeal swab sample from a Northern Pintail ( Anas acuta ) tested positive for clade 2.3.4.4b HPAI virus, out of 464 live-captured duck and goose samples. Of 195 sera samples from waterfowl screened for antibodies reactive to influenza A viruses, antibodies were found in 41–98% of samples collected from Emperor Goose ( Anser canagicus ), Cackling Goose, Black Brant, and Spectacled Eider ( Somateria fischeri ). In addition, 15–98% of the same sera samples were reactive to a clade 2.3.4.4b H5 antigen. Fewer Black Brant and Emperor Goose nests were found on long-term study plots during 2022 than in previous years. Collectively, we found that HPAI viruses affected at least seven species of wild birds inhabiting the region during 2022. The full scope of impacts of HPAI at this location during 2022 is unknown, but our data indicate that acute effects to avian population health on the Yukon-Kuskokwim Delta region were likely modest.

Alaska↗
USGS2001

Access to bird population data

Access to bird population data is critical for effective conservation planning and implementation. Although a tremendous volume of baseline data exists, it is often diffusely distributed and inaccessible to the resource manager and decision maker. A mechanism that facilitates assembly, documentation and delivery of avian data in a user-friendly manner is needed in order to integrate bird-related information resources across agencies and organizations. To address this fundamental need, the National Biological Information Infrastructure (NBII), in partnership with the U.S. Geological Survey's Patuxent Wildlife Research Center and the U.S. Fish and Wildlife Service, is developing a web-based interactive system that will focus on access to bird population and habitat data used in bird management and conservation. This system, known as the NBII Bird Conservation Node, will support planning and evaluation of bird conservation activities within the context of the North American Bird Conservation Initiative (NABCI), a framework for collaboration among organizations interested in bird conservation across North America. Initial development of the NBII Bird Conservation Node will focus on creating a prototype mapping application that will provide interactive access to data from the North American Breeding Bird Survey, the Colonial Waterbird Survey, the Breeding Waterfowl Population and Habitat Survey, and the Atlantic Flyway Mid-winter Waterfowl Survey. This prototype mapping application, to be available on-line at http://www.nbii.gov by Sep 2001, will lay the foundation for establishment of a Migratory Bird Data Center at Patuxent Wildlife Research Center, and will provide an opportunity for linking to and establishing partnerships with other sources of bird population and habitat data available over the Internet.

Book chapter↗
USGS1999

Le Conte's sparrows breeding in Conservation Reserve Program fields: precipitation and patterns of population change

The climate of the North American Great Plains is highly dynamic, with great year-to-year variability in precipitation and periodic, often extreme, wet and dry cycles (Bragg 1995). Drought is a major force of ecological disturbance on the Great Plains and has played a key role in directing the evolution of the grassland biota of this region (Knopf and Samson 1997). Although grassland birds may differ in their responses to enviromenental variations (Rotenberry and Wiens 1991), climatic variability and concomitant unpredictability of resources strongly influence populations of grassland birds across space and time (Wiens 1974, 1986; Cody 1985). Not surprisingly, breeding bird populations on the Great Plains are highly dynamic, exhibiting considerable annual variation in composition, abundance, and distribution (Johnson and Grier 1988, George et al. 1992, Zimmerman 1992, Igl and Johnson 1997). Recently, interest in grassland birds has increased with the recognition that many species are declining both continentally (Droege and Sauer 1994) and globally (Goriup 1988). Identification of the specific factors associated with grassland bird declines in North America, however, remains largely enigmatic (Herkert 1997), and it is complicated by the considerable annual fluctuations in grassland bird distribution and abundance (Igl and Johnson 1997). Although there is evidence that land-use changes on the breeding grounds may have contributed to grassland bird declines (e.g., Igl and Johnson 1997), there also is an indication that long-term drought conditions may have influenced recent population changes of some breeding birds on the Great Plains (Droege and Sauer 1989, Peterjohn and Sauer 1993, Bethke and Nudds 1995, Igl and Johnson 1997). Le Conte's Sparrow (Ammodramus leconteii) is a secretive grassland bird that breeds in central and southern Canada and the northcentral United States (Murray 1969). It winters primarily in the southern United States (Peterson 1980, 1990). Like populations of many grassland breeding birds in North America (Fretwell 1986, Igl and Johnson 1997), Le Conte's Sparrow populations exhibit numerical highs and lows depending on local moisture conditions (Peabody 1901, Stewart 1975, Knapton 1979, Zimmer 1979, Madden 1996). This observation, however, is based largely on anecdotal evidence or short-term observations. Long-term studies of Le Conte's Sparrow populations are limited. Le Conte's Sparrow is poorly represented on the North American Breeding Bird Survey (BBS) because of small sample sizes, poor coverage in the northern portion of its breeding range, and the species' furtive behavior (Sauer et al. 1995). Moreover, dramatic fluctuations in Le Conte's Sparrow abundance tend to obscure the species' long-term population trends on the BBS (Sauer et al. 1995). In this paper we examine long-term population changes of Le Conte's Sparrows breeding in perennial grassland fields enrolled in the Conservation Reserve Program (CRP) on the northern Great Plains. We discuss patterns of population change of Le Conte's Sparrows associated with changes in precipitation and moisture conditions.

Studies in Avian Biology↗
USGS2008

Tamarix as habitat for birds: Implications for riparian restoration in the Southwestern United States

Exotic vegetation has become a major habitat component in many ecosystems around the world, sometimes dramatically changing the vegetation community structure and composition. In the southwestern United States, riparian ecosystems are undergoing major changes in part due to the establishment and spread of the exotic Tamarix (saltcedar, tamarisk). There are concerns about the suitability of Tamarix as habitat for birds. Although Tamarix habitats tend to support fewer species and individuals than native habitats, Arizona Breeding Bird Atlas data and Birds of North America accounts show that 49 species use Tamarix as breeding habitat. Importantly, the relative use of Tamarix and its quality as habitat vary substantially by geographic location and bird species. Few studies have examined how breeding in Tamarix actually affects bird survivorship and productivity; recent research on Southwestern Willow Flycatchers has found no negative effects from breeding in Tamarix habitats. Therefore, the ecological benefits and costs of Tamarix control are difficult to predict and are likely to be species specific and site specific. Given the likelihood that high-quality native riparian vegetation will not develop at all Tamarix control sites, restoration projects that remove Tamarix but do not assure replacement by high-quality native habitat have the potential to reduce the net riparian habitat value for some local or regional bird populations. Therefore, an assessment of potential negative impacts is important in deciding if exotic control should be conducted. In addition, measurable project objectives, appropriate control and restoration techniques, and robust monitoring are all critical to effective restoration planning and execution. ?? 2008 Society for Ecological Restoration International.

Restoration Ecology↗
USGS2014

Aspidoscelis deppii (black-bellied racerunner). Predation by turkey vulture.

Aspidoscelis deppii is widely distributed from Veracruz and Michoacan, Mexico, to Costa Rica (Köhler et al. 2006. The Amphibians and Reptiles of El Salvador, Krieger Publishing Company, Malabar, Florida. 238 pp.). Neotropical lizards are abundant and common prey to all classes of terrestrial vertebrates, and bird predation of lizards is well known. The Turkey Vulture (Carthartes aura) is widely distributed from southern Canada south to South America and is present throughout the entire range of A. deppii, where it occupies a variety of open and forested habitats and feeds opportunistically on a wide range of wild and domestic carrion. While almost exclusively a scavenger, this species is known to rarely kill small animals or invertebrates (Kirk and Mossman 1998. In A. Poole [ed.], The Birds of North America Online. Cornell Lab of Ornithology, Ithaca; accessed 15 August 2013). An adult Turkey Vulture was collected during avian control to minimize wildlife hazards at the Aeropuerto Internacional de El Salvador (ca. 50 km SE of San Salvador, 13.4408°N 89.0556°W; datum WGS84) on 10 July 2012 and subsequently cataloged (USNM 646876) in the Bird Division at the National Museum of Natural History (NMNH) in Washington, DC. Dissection during preparation of the bird as a museum specimen revealed a male A. deppii (ca. 56 mm SVL) in the stomach. It was cataloged at the NMNH in the Division of Amphibians and Reptiles (USNM 580989). Tissue samples were removed from both the lizard and the bird and deposited in the biorepository at the NMNH. To the best of our knowledge, this is the first documented record identifying A. deppii as a prey item of the Turkey Vulture.

Aeropuerto Internacional de El Salvador↗
USGS2022

Large-scale distribution models for optimal prediction of Eastern black rail habitat within tidal ecosystems

Eastern black rails ( Laterallus jamaicensis jamaicensis ) are among the rarest and least-studied birds in North America and were recently listed as threatened under the U.S. Endangered Species Act. Spatial models that predict habitat quality across the subspecies range are therefore needed to inform conservation, recovery, and monitoring efforts for this rare bird. We used data from 47,585 call-broadcast surveys collected at 7906 sites over a 3-decade period (1990s, 2000s, 2010s; 23 total years) to build species distribution models for eastern black rails. We used hierarchical Bayesian occupancy models and predictive model selection to develop multi-scale models that optimally predict habitat suitability for eastern black rails within tidal wetlands while also accounting for imperfect detection of these cryptic birds during field surveys. We also used raster regression techniques to translate model predictions into 30-m resolution maps of habitat suitability for eastern black rails within tidal wetlands along the eastern seaboard of the United States. The model predicted suitability of breeding habitat as a function of wetland attributes (e.g., cover of high marsh and terrestrial border), hydrologic modification, and disturbance from human development measured over multiple spatial scales. We also found differences in habitat relationships for eastern black rails when compared to models that included both North American subspecies of black rail. Important results included negative effects of shrub-scrub wetlands, and strong positive effects of high marsh, terrestrial border, and impoundments on breeding season occupancy. Our study provides an example of integrating detection-non-detection data and modern statistical methods to build predictive distribution models for an extremely rare species, while also providing rigorous predictions of breeding habitat quality for the eastern black rail within tidal wetlands. These models will facilitate optimal monitoring, habitat conservation, and recovery planning efforts for eastern black rails and provide a foundation for future research and conservation of this imperiled bird.

Global Ecology and Conservation↗
USGS2014

Genomic characterization of H14 subtype influenza A viruses in New World waterfowl and experimental infectivity in mallards Anas platyrhynchos

Recent repeated isolation of H14 hemagglutinin subtype influenza A viruses (IAVs) in the New World waterfowl provides evidence to suggest that host and/or geographic ranges for viruses of this subtype may be expanding. In this study, we used genomic analyses to gain inference on the origin and evolution of H14 viruses in New World waterfowl and conducted an experimental challenge study in mallards ( Anas platyrhynchos ) to evaluate pathogenicity, viral replication, and transmissibility of a representative viral strain in a natural host species. Genomic characterization of H14 subtype IAVs isolated from New World waterfowl, including three isolates sequenced specifically for this study, revealed high nucleotide identity among individual gene segments (e.g. ≥95% shared identity among H14 HA gene segments). In contrast, lower shared identity was observed among internal gene segments. Furthermore, multiple neuraminidase subtypes were observed for H14 IAVs isolated in the New World. Gene segments of H14 viruses isolated after 2010 shared ancestral genetic lineages with IAVs isolated from wild birds throughout North America. Thus, genomic characterization provided evidence for viral evolution in New World waterfowl through genetic drift and genetic shift since purported introduction from Eurasia. In the challenge study, no clinical disease or lesions were observed among mallards experimentally inoculated with A/blue-winged teal/Texas/AI13-1028/2013(H14N5) or exposed via contact with infected birds. Titers of viral shedding for mallards challenged with the H14N5 IAV were highest at two days post-inoculation (DPI); however shedding was detected up to nine DPI using cloacal swabs. The distribution of viral antigen among mallards infected with H14N5 IAV was largely restricted to enterocytes lining the villi in the lower intestinal tract and in the epithelium of the bursa of Fabricius. Characterization of the infectivity of A/blue-winged teal/Texas/AI13-1028/2013(H14N5) in mallards provides support for similarities in viral replication and shedding as compared to previously described waterfowl-adapted, low pathogenic IAV strains in ducks.

PLoS ONE↗
USGS2009

Influence of Old World bluestem (Bothrichloa ischaemum) monocultures on breeding density of three grassland songbirds in Oklahoma

Despite persistent and widespread declines of grassland birds in North America, few studies have assessed differences between native grasslands and seeded monocultures as songbird habitat. In the Great Plains, many fields enrolled in the Conservation Reserve Program have been seeded to Old World bluestems (OWB), but there is evidence to suggest that OWB may not provide suitable conditions for several grassland bird species. Our objectives were to investigate the influence of OWB monocultures on vegetation structure, composition, and breeding densities of three common grassland bird species. In 2007, we used distance sampling to survey breeding songbirds in 6 native mixed grass prairie and 6 OWB fields in Garfield, Grant, and Alfalfa counties, Oklahoma. Native mixed grass prairie supported taller and denser vegetation, as well as greater forb cover than OWB fields. Breeding density of Grasshopper Sparrow ( Ammodramus savannarum ) was higher in OWB monocultures, while density of Dickcissel ( Spiza americana ) and Eastern Meadowlark ( Sturnella magna ) was similar among field types.

Oklahoma↗
USGS1994

Conservation reserve program: benefit for grassland birds in the northern plains

During the past few decades numbers of some species of upland-nesting birds in North America have declined. Duck species such as mallard (Anas platyrhynchos), northern pintail (A. acuta) and blue-winged teal (A. discors) have declined since the early 1970s and have remained low since 1985 (Caithamer et al. 1993). Some grassland-dependent nonwaterfowl species also have declined since 1966, as indicated by the North American Breeding Bird Survey (BBS) (Robbins et al. 1986). For prairie-nesting ducks, population declines can be attributed mostly to low recruitment, partially as a result of low nest success. Klett et al. (1988) concluded that nest success (probability of ≥1 egg of clutch hatches) in much of the U.S. Prairie Pothole Region was inadequate to maintain populations of the five most common upland-nesting duck species studied, and that predators were the most important cause of nest failure. Over the years, as grassland areas have been converted to cropland, ducks have concentrated their nesting in the remaining areas of available habitat, where predators such as red fox (Vulpes vulpes), striped skunk (Mephitis mephitis) and badger (Taxidea taxus) forage (Cowardin et al. 1983). The reasons for declining populations of grassland nonwaterfowl birds are not clear but the loss of suitable grassland-nesting habitat probably is an important factor. Currently, approximately 95 percent of the land in North Dakota is used for agricultural purposes, of which over 60 percent is used for annual crop production (Haugse 1990). Of the grassland that remains, 95 percent is used for livestock production. This probably had a severe impact on grassland bird species that seek idle grass cover for nesting. The 1985 and 1990 U.S. Farm Bills include provisions under the Food Security Act to fund a cropland-idling program called the Conservation Reserve Program (CRP). Over 36 million acres have been enrolled nationwide in the CRP since 1985 (Osborn 1993), and up to 25 percent of cropland in some counties has been converted primarily to grass. In North Dakota, nearly 3 million acres have been enrolled. Over 90 percent of the CRP plantings in North Dakota are grass and grass-legume mix composed primarily of wheatgrass (Agropyron spp.), smooth brome (Bromus inermis), alfalfa (Medicago saliva) and sweetclover (Melilotus spp.). Mixes of these species have been reported to attract high densities of nesting ducks (Duebbert and Kantrud 1974). According to the CRP provisions, the land must remain idle for the 10-year contract period, with the exception of emergency provisions for haying or grazing. CRP appears to have great potential for benefiting many species of grassland-nesting birds. There have been efforts to document the importance of the CRP to migratory birds in the Upper Great Plains of the U.S. Kantrud (1993) studied duck nest success in CRP cover and concluded that nest success was higher than in planted cover on U.S. Fish and Wildlife Service (FWS) Waterfowl Production Areas (WPAs). Johnson and Schwartz (1993a) measured the use of CRP fields by nonwaterfowl birds and reported that several species have responded positively by colonizing CRP fields. They concluded that CRP has the potential to help reverse the population declines of several species. We investigated the importance of CRP to upland-nesting ducks and certain other grassland-nesting birds. For ducks, we compared nest success in CRP cover with nest success in planted cover on WPAs in the same period (1992-93) and with that of an earlier period (1980-84). For nonwaterfowl, we used BBS data to compare the trends in populations of certain species found in CRP, for the periods 1966-86 (pre-CRP cover establishment) and 1987-92 (post-CRP cover establishment) in North Dakota.

North Dakota, South Dakota↗
USGS2011

Migratory flyway and geographical distance are barriers to the gene flow of influenza virus among North American birds

Despite the importance of migratory birds in the ecology and evolution of avian influenza virus (AIV), there is a lack of information on the patterns of AIV spread at the intra‐continental scale. We applied a variety of statistical phylogeographic techniques to a plethora of viral genome sequence data to determine the strength, pattern and determinants of gene flow in AIV sampled from wild birds in North America. These analyses revealed a clear isolation‐by‐distance of AIV among sampling localities. In addition, we show that phylogeographic models incorporating information on the avian flyway of sampling proved a better fit to the observed sequence data than those specifying homogeneous or random rates of gene flow among localities. In sum, these data strongly suggest that the intra‐continental spread of AIV by migratory birds is subject to major ecological barriers, including spatial distance and avian flyway.

California, Oregon, Washington↗
USGS2023

Baiting and banding: Expert opinion on how bait trapping may influence the occurrence of highly pathogenic avian influenza (HPAI) among dabbling ducks

A Eurasian lineage highly pathogenic avian influenza virus (HPAIV) of the clade 2.3.4.4b (Goose/Guangdong lineage) was detected in migratory bird populations in North America in December 2021, and it, along with its reassortants, have since caused wild and domestic bird outbreaks across the continent. Relative to previous outbreaks, HPAIV cases among wild birds in 2022 exhibited wider geographic extent within North America and higher levels of mortality, suggesting the potential for population-level impacts. Given the possible conservation implications of HPAIV in wild birds, natural resource managers have sought guidance on actions that may mitigate negative effects of disease among North American bird populations, including modification of existing management practices. Banding of waterfowl is a critical tool for population management for several harvested species in North America, but some banding techniques, such as bait trapping, can lead to increased congregation of waterfowl, potentially altering HPAIV transmission. We used an expert opinion exercise to assess how bait trapping of dabbling ducks in Canada may influence HPAIV transmission and wild bird health. The expert group found that it is moderately likely that bait trapping of dabbling ducks in wetlands will significantly increase the transmission of HPAIV among individual ducks, but there is a low probability that this will result in significant population-level effects on North American dabbling ducks. Considering the lack of empirical work studying how capture and handling methods may change transmission of HPAIV among waterfowl, as well as the importance of bait trapping for waterfowl management in North America, future work should focus on filling knowledge gaps pertaining to the influence of baiting on HPAIV occurrence to better inform banding procedures and management decision making.

Journal of Wildlife Diseases↗
USGS1976

Report of the American Ornithologists' Union Committee on Conservation 1975-76

This Committee's report for 1974-75 (Marshall et al. 1975, Auk 92 (4, Suppl.): lB-16B) summarized activities affecting bird conservation in the United States and Canada since 1973, including new legislation, international activities, avian conflicts with industrial and population growth, and habitat preservation. It also summarized the status of many of the endangered birds of North America, and a few critically endangered species elsewhere. The concern expressed in the report for greater participation of scientists outside government in the affairs of government has led to the formation of an AOU Committee on Public Responsibility. This report focuses on avian conservation problems in two areas, Puerto Rico and the islands of the Bering Sea. Both areas have conservation problems that are significant to ornithologists, there have been major new developments in the status of the birds and their habitats in these areas in the last few years, yet neither area has received the attention this committee feels it deserves. The Committee thanks Noel Snyder and George Gee for their contributions to this report.

The Auk↗
USGS2004

How we can learn more about the Cerulean Warbler ( Dendroica cerulea )

A sense of urgency attends the study of species of concern, like the Cerulean Warbler ( Dendroica cerulea ). Sharpened by Robbins et al. (1992) and Hamel (1992), such concern prompted the U.S. Department of the Interior, Fish and Wildlife Service (USFWS) to commission a status assessment of the Cerulean Warbler (Hamel 2000a). Shortly after the status review was published, a petition (Ruley 2000) was delivered to the USFWS urging that the species be listed as “threatened” under the Endangered Species Act of 1973. The account of the Cerulean Warbler in the Birds of North America series also appeared that year (Hamel 2000b). Substantial attention is currently focused on the species, and the Cerulean Warbler Technical Group (CWTG) was formed in 2002 (see Appendix). This overview consists of two parts. The first, prepared primarily by P.B.H., attempts to summarize current knowledge and suggest productive avenues to pursue in our efforts to understand the biology and conserve populations of Cerulean Warblers. The second, written by D.K.D. and P.D.K., is a summary of the structure and priorities of the CWTG, an organization that can spur and facilitate research and conservation action directed at this species and serve as a model for conservation of other forest birds (Appendix). Further information on Cerulean Warblers and activities of the Cerulean Warbler Technical Group can be found on the CWTG website (see Acknowledgments).

The Auk↗
USGS2016

Combining citizen science species distribution models and stable isotopes reveals migratory connectivity in the secretive Virginia rail

Stable hydrogen isotope (δD) methods for tracking animal movement are widely used yet often produce low resolution assignments. Incorporating prior knowledge of abundance, distribution or movement patterns can ameliorate this limitation, but data are lacking for most species. We demonstrate how observations reported by citizen scientists can be used to develop robust estimates of species distributions and to constrain δD assignments. We developed a Bayesian framework to refine isotopic estimates of migrant animal origins conditional on species distribution models constructed from citizen scientist observations. To illustrate this approach, we analysed the migratory connectivity of the Virginia rail Rallus limicola , a secretive and declining migratory game bird in North America. Citizen science observations enabled both estimation of sampling bias and construction of bias-corrected species distribution models. Conditioning δD assignments on these species distribution models yielded comparably high-resolution assignments. Most Virginia rails wintering across five Gulf Coast sites spent the previous summer near the Great Lakes, although a considerable minority originated from the Chesapeake Bay watershed or Prairie Pothole region of North Dakota. Conversely, the majority of migrating Virginia rails from a site in the Great Lakes most likely spent the previous winter on the Gulf Coast between Texas and Louisiana. Synthesis and applications . In this analysis, Virginia rail migratory connectivity does not fully correspond to the administrative flyways used to manage migratory birds. This example demonstrates that with the increasing availability of citizen science data to create species distribution models, our framework can produce high-resolution estimates of migratory connectivity for many animals, including cryptic species. Empirical evidence of links between seasonal habitats will help enable effective habitat management, hunting quotas and population monitoring and also highlight critical knowledge gaps.

Journal of Applied Ecology↗