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At least 253 records · Page 14Linked to original sources

U.S. national park units as breeding bird habitat: A comparison of species prevalence and land cover across the midwestern and central United States

The value of national parks as bird habitat depends not only on local conditions within the parks, but also on the landscape habitat matrices in which they are located. However, the influences of local and landscape habitat matrices on birds vary by species and have not been quantified. Similarly, the trends of land cover types through time have not been systematically quantified for Midwest Region national parks and the landscapes around them, despite evidence of ongoing habitat loss exacerbated by climate change and human population growth. Managers and policy makers can use this information to understand and sustain the contribution of parks to our Nation’s avifauna. We developed models using North American Breeding Bird Survey (BBS) data collected on routes from across the central United States. The models were used to predict occupancy of bird species of concern in 32 national park units across nine Bird Conservation Regions in the Midwest based on land cover in and around those parks. We then compared these predictions with data collected through National Park Service (NPS) bird surveys at each park to determine if bird species of concern were more or less prevalent than expected. In each park, the mean difference between observed species detections and mean predicted detections indicates that most species are less frequently detected in the parks than predicted. However, when the range of uncertainty of predictions is considered, only 21% of park-bird combinations showed strong evidence (95%) of differing from expectation. Of these, species were less common than expected in the park in all but two cases. These results indicate that some bird species of concern occupy sites in Midwest Region national park units at a rate roughly comparable to sites with similar land cover in the Bird Conservation Region (BCR) in which they occur. However, for one in five species-park combinations, parks appear to be less occupied than comparable sites elsewhere.

Midwest region

H7N9 influenza A virus in turkeys in Minnesota

Introductions of H7 Influenza A virus (IAV) from wild birds into poultry have been documented worldwide, resulting in varying degrees of morbidity and mortality. H7 IAV infection in domestic poultry has served as a source of human infection and disease. We report the detection of H7N9 subtype IAV in Minnesota turkey farms during 2009 and 2011. The full-genome was sequenced from eight isolates as well as the hemagglutinin (HA) and neuraminidase (NA) gene segments of H7 and N9 virus subtypes for 108 isolates from North American wild birds between 1986 and 2012. Through maximum likelihood and coalescent phylogenetic analyses, we identified the recent H7 and N9 IAV ancestors of the turkey-origin H7N9 IAV, estimated the time and geographic origin of the ancestral viruses, and determined the relatedness between the 2009 and the 2011 turkey-origin H7N9 IAV. Analyses supported that the 2009 and the 2011 viruses were distantly related genetically, suggesting that the two outbreaks arose from independent introduction events from wild birds. Our findings further support that the 2011 MN turkey-origin H7N9 virus was closely related to H7N9 IAV isolated in poultry in Nebraska during the same year. Although the precise origin of the wild-bird donor of the turkey-origin H7N9 IAV could not be determined, our findings suggest that, for both the NA and HA gene segments, the MN turkey-origin H7N9 viruses were related to viruses circulating in wild birds between 2006 and 2011 in the Mississippi flyway.

Minnesota

Assessing allowable take of migratory birds

Legal removal of migratory birds from the wild occurs for several reasons, including subsistence, sport harvest, damage control, and the pet trade. We argue that harvest theory provides the basis for assessing the impact of authorized take, advance a simplified rendering of harvest theory known as potential biological removal as a useful starting point for assessing take, and demonstrate this approach with a case study of depredation control of black vultures (Coragyps atratus) in Virginia, USA. Based on data from the North American Breeding Bird Survey and other sources, we estimated that the black vulture population in Virginia was 91,190 (95% credible interval = 44,520?212,100) in 2006. Using a simple population model and available estimates of life-history parameters, we estimated the intrinsic rate of growth (rmax) to be in the range 7?14%, with 10.6% a plausible point estimate. For a take program to seek an equilibrium population size on the conservative side of the yield curve, the rate of take needs to be less than that which achieves a maximum sustained yield (0.5 x rmax). Based on the point estimate for rmax and using the lower 60% credible interval for population size to account for uncertainty, these conditions would be met if the take of black vultures in Virginia in 2006 was < 3,533 birds. Based on regular monitoring data, allowable harvest should be adjusted annually to reflect changes in population size. To initiate discussion about how this assessment framework could be related to the laws and regulations that govern authorization of such take, we suggest that the Migratory Bird Treaty Act requires only that take of native migratory birds be sustainable in the long-term, that is, sustained harvest rate should be < rmax. Further, the ratio of desired harvest rate to 0.5 x rmax may be a useful metric for ascertaining the applicability of specific requirements of the National Environmental Protection Act.

Journal of Wildlife Management

Forest fragmentation and bird community dynamics: Inference at regional scales

With increasing fragmentation of natural areas and a dramatic reduction of forest cover in several parts of the world, quantifying the impact of such changes on species richness and community dynamics has been a subject of much concern. Here, we tested whether in more fragmented landscapes there was a lower number of area-sensitive species and higher local extinction and turnover rates, which could explain higher temporal variability in species richness. To investigate such potential landscape effects at a regional scale, we merged two independent, large-scale monitoring efforts: the North American Breeding Bird Survey (BBS) and the Land Use and Land Cover Classification data from the U.S. Geological Survey. We used methods that accounted for heterogeneity in the probability of detecting species to estimate species richness and temporal changes in the bird communities for BBS routes in three mid-Atlantic U.S. states. Forest breeding bird species were grouped prior to the analyses into area-sensitive and non-area-sensitive species according to previous studies. We tested predictions relating measures of forest structure at one point in time (1974) to species richness at that time and to parameters of forest bird community change over the following 22-yr-period (1975–1996). We used the mean size of forest patches to characterize landscape structure, as high correlations among landscape variables did not allow us to disentangle the relative roles of habitat fragmentation per se and habitat loss. As predicted, together with lower species richness for area-sensitive species on routes surrounded by landscapes with lower mean forest-patch size, we found higher mean year-to-year rates of local extinction. Moreover, the mean year-to-year rates of local turnover (proportion of locally new species) for area-sensitive species were also higher in landscapes with lower mean forest-patch size. These associations were not observed for the non-area-sensitive species group. These results suggest that landscape structure may influence forest bird communities at regional scales through its effects on the total number of species but also on the temporal rates of change in community composition. Evidence for higher rates of local extinction and turnover in more fragmented landscapes suggests that bird communities function as metapopulations at a regional scale, and points out the importance of colonizations and recolonizations from surrounding landscapes to local community dynamics. Further, our results illustrate that the methods used to estimate the community parameters can be a powerful statistical tool in addressing questions relative to the dynamics of communities.

Ecology

Geographic analysis of species richness and community attributes of forest birds from survey data in the mid-Atlantic integrated assessment region

Species richness of local communities is a state variable commonly used in community ecology and conservation biology. Investigation of spatial and temporal variations in richness and identification of factors associated with these variations form a basis for specifying management plans, evaluating these plans, and for testing hypotheses of theoretical interest. However, estimation of species richness is not trivial: species can be missed by investigators during sampling sessions. Sampling artifacts can lead to erroneous conclusions on spatial and temporal variation in species richness. Here we use data from the North American Breeding Bird Survey to estimate parameters describing the state of bird communities in the Mid-Atlantic Assessment (MAIA) region: species richness, extinction probability, turnover and relative species richness. We use a recently developed approach to estimation of species richness and related parameters that does not require the assumption that all the species are detected during sampling efforts. The information presented here is intended to visualize the state of bird communities in the MAIA region. We provide information on 1975 and 1990. We also quantified the changes between these years. We summarized and mapped the community attributes at a scale of management interest (watershed units).

Delaware, Maryland, Pennsylvania, Virginia, West V

Galliform exclusion from the Migratory Bird Treaty Act has produced an alternate conservation path, but no evidence for differences in population status

The Migratory Bird Treaty Act (MBTA) is critical to avian conservation in the United States, both through its protection of migratory birds and as a catalyst for a century of coordinated avian conservation. While more than 1,000 species are protected by MBTA, of extant bird species native to the continental U.S., only 20 species belonging to the order Galliformes are explicitly excluded. Management of galliforms has occurred largely without direct federal oversight, placing this group on a fundamentally different conservation path during the century following MBTA passage. In this paper, we review the historical context and biological justification for exclusion of galliforms from MBTA and synthesize how their present-day conservation differs from that of migratory birds. We find the most prominent difference between the two groups involves the scope of coordination among stakeholders. The U.S. government, primarily via the Department of Interior, acts as de facto coordinating body for migratory bird conservation and plays the central role in oversight, funding, and administration of management in the United States. In contrast, galliform management falls primarily to individual state wildlife agencies, and coordinated conservation efforts have been more ad hoc and unevenly spread across species. Migratory birds benefit from an almost universally greater scope of research and monitoring, scale of habitat conservation, and sophistication of harvest management compared with galliforms. Galliform harvest management plans, in particular, are less likely to use measurable objectives, reporting of uncertainty in population parameters, and explanation of harvest management techniques. Based on a review of species status lists (e.g., the U.S. Endangered Species Act), we found no evidence that galliforms were more frequently listed than migratory species. Regional trend estimates from the North American Breeding Bird Survey (BBS) were more likely to be negative for galliforms over the period 1966–2015, but this was primarily driven by Northern Bobwhite ( Colinus virginianus ). Data to assess galliform population status are generally poor, which complicates assessment for roughly half of galliform species. Increased support for coordination among state agencies and other stakeholders, similar to that applied to migratory birds, could help to ensure that galliform conservation is poised to tackle forthcoming challenges associated with global change.

North America

Atlantic Flyway review: Region IV - Fall 2003

We welcome the Eden Mill station in northeastern Maryland to Region IV this year. With three stations reporting their worst year ever, we really need to be refreshed. After a cool and wet July, August was hot and wet in the east. Temperatures in September remained close to normal, but thanks to tropical storms Henri (6-8 Sep) and Isabel (18 Sep), rainfall was excessive in the Chesapeake Bay states. The entire Northeast had cool weather in October, starting with an early freeze on 3 Oct that triggered some good banding days in our region. Precipitation was unusually spotty in October, but plentiful at most of the Region IV stations. November temperatures were consistently well above the norm, starting with a record-breaking 81 ø in Baltimore on the 1 st . Four of the five Maryland stations had their best day on 19 or 20 Oct. One might expect some of the Virginia coastal stations, Chincoteague, Kiptopeke, and Back Bay, to share the same best day, but they did not. Three stations reported an increase in birds per net hour this year, while seven had a decline. Summarizing the changes in rank in Table 2, Gray Catbird was the species with the most (5) increases in rank (in excess of decreases), followed by junco (4) and Myrtle Warbler and Swamp Sparrow (3 each). Yellowthroat had the most decreases (5), followed by redstart (3). Myrtle Warbler (4572) was once again the most commonly banded species in Region IV, followed by White-throated Sparrow (1723), Gray Catbird (1349), and Western Palm Warbler (1090). Michelle Davis' station on Key Biscayne is the envy of the rest of us. Her top eight species were all warblers and there was not a Myrtle among them. Imagine having Parula, Prairie, and Worm-eating warblers fighting for sixth place! Not showing among the top ten, however, are other surprises. Several banders commented on Sawwhet Owls and Bicknell's Thrushes. Deanna Dawson banded a Cerulean Warbler at Patuxent. Danny Bystrak caught 138 Swamp Sparrows at Jug Bay. In addition to two Clay-colored Sparrows and two Gambel's White-crowns, Jim Gruber at Chino Farms had his first Le Conte's Sparrow and a state high of 39 Lincoln's Sparrows. Dick Roberts' new species at Chincoteague included Yellow-throated and Mourning warblers, while Jethro Runco's best birds at Kiptopeke included S edge Wren and Golden-winged Warbler. The Simpsons at Back Bay finally identified a Western Wood-Pewee after many years of trying. Unusual for Michelle Davis' warbler station on Key Biscayne were Tennessee, Chestnut-sided, and Bay-breasted warblers.

North American Bird Bander

Role of banding in forest conservation strategy in eastern Guatemala

In response to a request from FUNDAECO, a Guatemalan non-government organization, we worked with them to develop a conservation strategy for the Cerro San Gil Protected Area and surrounding private lands. Volunteer banders from a dozen states and Canadian provinces assisted in long-term monitoring of populations of resident and migratory species through banding and point counts. Guatemalan students were trained to continue the research and initiate other conservation projects. Banding data helped demonstrate habitat and elevational affiliations, effects of habitat fragmentation, site fidelity, survival rates, local movements, and presence of rare species not otherwise detected. Banding was also an excellent teaching tool and provided videos for conservation programs on Guatemala national television. Roadside and off-road Breeding Bird Survey transects were used to map distribution of breeding species on habitat maps derived from satellite imagery, and point count surveys on private lands were used to identify prime habitats that warrant protection through conservation easements--a new concept for Central America.

North American Bird Bander

Atlantic Flyway review: Piedmont-Coastal Plain, Region IV, Fall 1999

In a slight reorganization, the Mount Nebo station in the mountains of western Maryland near Oakland was moved to Region III (Western Ridge), in exchange for Lakeshore Estates in Leon County, Florida, which we welcome to Region IV. This was the year of the hurricane in Region IV, with the majority of stations commenting on summer drought, persistent easterly winds, or hurricanes. Nine of the ten stations that operated in both 1998 and 1999 banded fewer birds in the 1999 season, the notable exception being Chino Farms, which jumped from 5193 to 8225 birds and also had a 3% increase in birds per 100 net-hours. Summing across these ten stations: 27,911 birds were banded in 1998, 24,753 in 1999, a decrease of 11%. (Net-hours are not available for all sites for 1998). Yellow-rumped Warbler was again the most commonly banded, followed again by Common Yellowthroat (which was among the top ten species at all sites except Lakeshore Estates at Tallahassee), and with the American Goldfinch a surprise in third place.

North American Bird Bander

Three geese resembling Gray-Bellied Brant/Lawrence's Brant from Long Island, New York

Three oddly plumaged brant, intermediate in several respects between 'Atlantic' or 'Pale-bellied Brant' (hrota) and ?Black Brant? (nigricans) were photographed and described on western Long Island, New York during 2002 (two in March, the third in October). Their plumage corresponded to that of the little-studied, and apparently genetically distinctive small population known among goose biologists as 'Gray-bellied Brant,' which breeds only on a few islands in the western Canadian High Arctic, stages in migration in the inner Aleutians, and winters in a small portion of the Greater Puget Sound area. But Gray-bellied Brant also wander, having recently been found in winter as far from Puget Sound as Baja California in the west, and Iceland and the British Isles to the east?these strays presumably having migrated southwest with Pacific-wintering nigricans and southeast with Atlantic-wintering hrota, respectively. Despite their tendency to associate with locally wintering hrota and nigricans, mixed pairs or hybrid young involving these vagrants have never been demonstrated in North America?nor have mixed pairs or hybrid young between hrota and nigricans, despite widespread belief to the contrary. Complicating the picture is that the type specimen of nigricans, a distinctive New Jersey specimen collected in 1846, also differs from 'true' Pacific Coast Black Brant in several respects, in a manner qualitatively similar to the LI birds described herein. The appearance of the type, often referred to informally as 'Lawrence?s Brant,' differs from typical Black Brant to such an extent that Delacour and Zimmer (1952) rejected application of nigricans to Pacific Black Brant, to which the name orientalis would have to be applied instead. Recent examination of museum specimens of breeding- and winter-area Gray-bellies confirms that Lawrence?s Brant closely resembles some of them?as do these three Long Island birds. Whatever the ultimate statuses of Gray-bellied and Lawrence's Brant prove to be?and however the relationships among them and the three currently recognized other taxa of brant eventually play out?birds resembling Gray-bellied/Lawrence?s are occurring on both Atlantic and Pacific coasts and perhaps also in interior North America, so knowledge of their plumage variation should now be factored into the identification of all oddly-plumaged or out-of-range brant, but especially of putative 'nigricans' inland or on the Atlantic Coast.

North American Birds

Atlantic Flyway review: Region V: Laurel, Prince Georges County, MD (390-0765)

Nets were operated at this suburban backyard station before and after work during the week, and all day on as many weekends as possible, from 23 August to 30 November. A trip to Spain interrupted banding in mid-September and accounted for the drop in both species and individuals banded. This also explains the 66% drop in Gray Catbirds, which was by far my most common species last year. As in past years, no netting was done within 15 m of the bird feeders, and no traps were baited until the nets were removed in December. White-throated Sparrows (9) and Carolina Chickadees (7) accounted for half of my returns. The oldest returns were a 6-year-old White-throated Sparrow and a 7-year-old Carolina Chickadee. The only species banded in unusually large numbers were American Robin and Black-throated Blue Warbler. A Red-shouldered Hawk and a Golden-winged Warbler raised the species total for this station to 112. Three birds remained here long enough to increase their weight by more than 30%: an HY female Black-and-white Warbler arrived on 29 August with a weight of 11.2 g and was last captured on 5 September with a weight of 17.1 g. It took an HY Ovenbird 24 days to increase from 20.8 g to the 28.2 g that it weighed when last caught on 13 October. A Swainson's Thrush, on the other hand, went from 36.5 g to 48.1 g between 10 and 14 October. Other heavy-weights were Hairy Woodpecker, 74.4 g; Blue Jay, 103.2 g; Gray Catbird, 46.4 g; Wood Thrush, 64.1 g; and White-eyed Vireo, 15.0 g.

Maryland

Atlantic Flyway review: Piedmont-Coastal Plain, Region IV, Fall 1999: Patuxent powerline right-of-way (390-0764)

Fall 1999 was among the poorest seasons in this banding station's 20 years of operation. Record high capture totals were set for only two species: Ruby-throated Hummingbird (41 individuals captured, none banded; previous high 21) and White-breasted Nuthatch (two individuals banded; previous high, one). The only other species that stood out as being unusually numerous was Blackpoll Warbler, for which the banding total (33 birds) was the highest since 1988. Bandings of several species (Red-eyed Vireo, Tennessee Warbler, Nashville Warbler, Ovenbird, Hooded Warbler, Canada Warbler, Eastern Towhee, and Field Sparrow) were at record lows, and bandings of many other species were below the long-term (1980-1998) mean. The number of species banded was also below the long-term mean of 86 species, and tied the previous low. Possible contributing factors included drought conditions in Maryland and elsewhere in the East, which may have influenced nesting productivity and migration dates for some species; Hurricanes Dennis and Floyd, which influenced East Coast weather through much of September; the unprecedented scarcity of Hercules' Club ( Aralia spinosa ) fruits at the banding station; and occasional visits by a gray fox, which reduced operation of some nets in October and November. A season highlight was the August capture of 37 Red-eyed Vireos banded at this station in previous years, including a bird banded in August 1989. These are almost certainly locally nesting birds that feed on the abundant fruits of Viburnum dentatum in the powerline right-of-way in late summer. Regular assistants at the banding station included Woody Martin, Susie Michaelson, Jane Nicolich, Gemma Radko, Jack Saba, Julie Tomita, and Laurie Walter. Danny Bystrak and Mary Gustafson each served as bander-in-charge on several mornings.

Maryland

A technique to prevent capturing birds in unattended, furled mist nets

A technique was developed to prevent the inadvertent capturing of birds in unattended mist nets left in place for long periods of time. This was accomplished by placing furled nets on top of 9-inch wide strips of 30-pound roofing felt secured to the ground between net support poles. All materials used are widely available and procedures used to make the felt strips and install them are described.

North American Bird Bander

Response of vegetation and breeding birds to the removal of cattle on the San Pedro River, Arizona (U.S.A.)

In late 1987 cattle were removed from the San Pedro Riparian National Conservation Area ( NCA ) in southeastern Arizona ( U.S.A. ). We monitored vegetation density and abundance of birds during the breeding season during 1986a??1990 in riparian, mesquite grassland, and Chihuahuan desert-scrub communities in the NCA. The density of herbaceous vegetation increased four- to six-fold in riparian and mesquite grassland communities. Little change occurred in herbaceous vegetation in desert scrub, or in the density of shrubs or trees in any of the communities. Of 61 bird species for which sufficient data were collected, mean detections per kilometer increased for 42 species, 26 significantly, and decreased for 19 species, 8 significantly. The number of individuals of all avian species detected on surveys increased each year from 103/kilometer in 1986 to 221/kilometer in 1991, an average annual increase of 23% ( p < 0.001 ). The largest increases occurred in riparian species, open-cup nesters, Neotropical migrants, and insectivores. Species of the Chihuahuan desert-scrub, in which vegetation changed the least, showed the smallest increases. Only a few of the species showed increasing regional trends for the same period, as demonstrated by the North American Breeding Bird Survey; thus, increases on the San Pedro Riparian NCA were likely caused by the change in local conditions, not by regional effects. Our results suggest that removing cattle from riparian areas in the southwestern United States can have profound benefits for breeding birds.

Conservation Biology

A hierarchical spatial model of avian abundance with application to Cerulean Warblers

Surveys collecting count data are the primary means by which abundance is indexed for birds. These counts are confounded, however, by nuisance effects including observer effects and spatial correlation between counts. Current methods poorly accommodate both observer and spatial effects because modeling these spatially autocorrelated counts within a hierarchical framework is not practical using standard statistical approaches. We propose a Bayesian approach to this problem and provide as an example of its implementation a spatial model of predicted abundance for the Cerulean Warbler (Dendroica cerulea) in the Prairie-Hardwood Transition of the upper midwestern United States. We used an overdispersed Poisson regression with fixed and random effects, fitted by Markov chain Monte Carlo methods. We used 21 years of North American Breeding Bird Survey counts as the response in a loglinear function of explanatory variables describing habitat, spatial relatedness, year effects, and observer effects. The model included a conditional autoregressive term representing potential correlation between adjacent route counts. Categories of explanatory habitat variables in the model included land cover composition and configuration, climate, terrain heterogeneity, and human influence. The inherent hierarchy in the model was from counts occurring, in part, as a function of observers within survey routes within years. We found that the percentage of forested wetlands, an index of wetness potential, and an interaction between mean annual precipitation and deciduous forest patch size best described Cerulean Warbler abundance. Based on a map of relative abundance derived from the posterior parameter estimates, we estimated that only 15% of the species' population occurred on federal land, necessitating active engagement of public landowners and state agencies in the conservation of the breeding habitat for this species. Models of this type can be applied to any data in which the response is counts, such as animal counts, activity (e.g.,nest) counts, or species richness. The most noteworthy practical application of this spatial modeling approach is the ability to map relative species abundance. The functional relationships that we elucidated for the Cerulean Warbler provide a basis for the development of management programs and may serve to focus management and monitoring on areas and habitat variables important to Cerulean Warblers.

Ecological Applications

A brief report on the illegal cage-bird trade in southern Florida: a potentially serious negative impact on the eastern population of Painted Bunting (Passerina ciris)

Populations of Painted Bunting (Passerina ciris) have been declining annually over the past 35 years. A cursory survey indicates that illegal trapping of Painted Buntings for a black market cage-bird trade is widespread in southeastern Florida. Coupled with other negative factors confronting the eastern population, the trapping of buntings for the cagebird trade may, in time, produce dire results for this native songbird. Law enforcement personnel need to continue to monitor the illegal activity of trapping native passerines for the local songbird market and to continue to arrest those who support it.

North American Birds

A flexible framework for N-mixture occupancy models: Applications to breeding bird surveys

Estimating species abundance under imperfect detection is a key challenge in biodiversity conservation. The N -mixture model, widely recognized for its ability to distinguish between abundance and individual detection probability without marking individuals, is constrained by its stringent closure assumption, which leads to biased estimates when violated in real-world settings. To address this limitation, we propose an extended framework based on a development of the mixed Gamma-Poisson model, incorporating a community parameter that represents the proportion of individuals consistently present throughout the survey period. This flexible framework generalizes both the zero-inflated type occupancy model and the standard N -mixture model as special cases, corresponding to community parameter values of 0 and 1, respectively. The model’s effectiveness is validated through simulations and applications to real-world datasets, specifically with 5 species from the North American Breeding Bird Survey and 46 species from the Swiss Breeding Bird Survey, demonstrating its improved accuracy and adaptability in settings where strict closure may not hold.

Biometrics

An efficient method of capturing Painted Buntings and other small granivorous passerines

To study survival in the eastern breeding population of the Painted Bunting (Passerina ciris), I developed a technique to capture a large sample of buntings for color marking with leg-bands. This involved the use of bird feeders and an array of three short mist nets located at 40 sites in four states, each site meeting five specific criteria. In five years of mist netting (1999-2003), 4174 captures (including recaptures) of Painted Buntings were made in 3393 net-hours or 123 captures per 100 net-hours. The technique proved to be effective and efficient, and may have broad application for capturing large numbers of small granivorous passerines.

North American Bird Bander