The disproportionate effect of global warming on the arrival dates of short-distance migratory birds in North America

Recent studies have shown that, in response to global climate change, diverse avian taxa are now nesting measurably earlier (< 10 days) in both the United States and Britain. Similarly, several studies on European birds have now demonstrated that a variety of species (although not all) are arriving increasingly early. However, surprisingly, widespread changes in North American migrant phenology have not been demonstrated. It is hypothesized that short-distance migrants (birds that winter in the southern United States) may be quicker to adapt to climate change than long-distance migrants (birds that winter south of the United States), as short-distance migrants can respond to meteorological cues indicating weather conditions to the north whereas long-distance migrants must rely on photoperiod. This study examined the first arrival dates of 103 migrant birds in New York and Massachusetts and found that, on average, all migrants arrived significantly earlier during the period 1951–1993 than the period 1903–1950. From 1951–1993 birds wintering in the southern United States arrived on average 13 days earlier while birds wintering in South America arrived 4 days earlier. Although a change in observer effort cannot be quantified and may be a source of bias, a comparison of the numbers of reporting observers during the 1930s and the 1980s revealed no significant difference. These results are consistent with those expected under a scenario of global warming.     

An estimate of avian mortality at communication towers in the United States and Canada

Avian mortality at communication towers in the continental United States and Canada is an issue of pressing conservation concern. Previous estimates of this mortality have been based on limited data and have not included Canada. We compiled a database of communication towers in the continental United States and Canada and estimated avian mortality by tower with a regression relating avian mortality to tower height. This equation was derived from 38 tower studies for which mortality data were available and corrected for sampling effort, search efficiency, and scavenging where appropriate. Although most studies document mortality at guyed towers with steady-burning lights, we accounted for lower mortality at towers without guy wires or steady-burning lights by adjusting estimates based on published studies. The resulting estimate of mortality at towers is 6.8 million birds per year in the United States and Canada. Bootstrapped subsampling indicated that the regression was robust to the choice of studies included and a comparison of multiple regression models showed that incorporating sampling, scavenging, and search efficiency adjustments improved model fit. Estimating total avian mortality is only a first step in developing an assessment of the biological significance of mortality at communication towers for individual species or groups of species. Nevertheless, our estimate can be used to evaluate this source of mortality, develop subsequent per-species mortality estimates, and motivate policy action.     

Large forests enhance songbird nesting success in agricultural‐ dominated landscapes of the Midwestern US

We studied the effects of habitat composition and distance from edges on nesting success and brood parasitism of forest birds in the Kaskaskia River Bottoms, one of the largest remaining tracts of floodplain forest in the agricultural Midwestern United States. Our goal was to help the private landowners, who have maintained this region in forest cover, enhance the value of these forests for nesting birds. We measured nest predation rates and levels of brood parasitism of four species, the indigo bunting Passerina cyanea, Acadian flycatcher Empidonax virescens, northern cardinal Cardinalis cardinalis and prothonotary warbler Protonotaria citrea in relation to distances from natural and anthropogenic edges and proportion of natural and anthropogenic habitats within fixed radii around nests. We predicted that nesting success would increase with increasing distance from anthropogenic habitats and with increasing land cover in natural habitats. Our results showed no strong effect of any of these variables on avian nesting success, although parasitism levels increased slightly with increasing proportion of agricultural land around nests for two of the species. Nevertheless, nesting success for at least three of these species was much higher than in more fragmented forest tracts elsewhere in the agricultural Midwest where most forest tracts appear to be population sinks for most species. These results suggest that forest tracts in the Kaskaskia may be saturated with nest predators and brood parasites, but are not super‐saturated in a way that would cause these tracts to become ‘black hole’ population sinks. Our data further suggest that, as long as landowners maintain their private landholdings in forest cover, the details of how they manage their land may have little effect on songbird nesting success. These results also suggest that reforestation efforts in areas with many openings may still benefit forest birds.     

Five new species of Rhinonyssidae (Mesostigmata) and one new species of Dermanyssus (Mesostigmata: Dermanyssidae) from birds of Alberta and Manitoba, Canada

Three major lineages of mites are parasitic in the nasal passages of birds, i.e., Rhinonyssidae (Mesostigmata), Ereynetidae (Prostigmata), Cytoditidae, and Turbinoptidae (Astigmata). The most diverse family of avian nasal mites is Rhinonyssidae, which include obligate hematophagous endoparasites of nonratite birds worldwide. Nasal mites have been surveyed extensively in the United States, yet there has never been a Canadian survey. There are only 4 published, and 3 unpublished, rhinonyssid species records from birds in Canada. While surveying the nasal mites associated with birds of Alberta and Manitoba (western Canada), 1 new species of Dermanyssus and 5 new species of Rhinonyssidae were recovered. Herein, I describe and illustrate Dermanyssus diphyes n. sp., Ptilonyssus calvaria n. sp., P. nivalis n. sp., P. pinicola n. sp., P. plesiotypicus n. sp., and Sternostoma setifer n. sp.     

Response of grassland birds to management in national battlefield parks

Grassland birds are in steep decline, with population declines reported in 74% of North American grassland species in the past 50 years. Declines are particularly severe in the eastern United States where they are influenced by habitat loss and alteration due to urbanization, forest regrowth, and agricultural intensification. The United States National Park Service maintains civil war battlefields in the eastern United States as historical and cultural parks that may also provide habitat refuge for grassland birds within an increasingly urbanized matrix. To assess the conservation importance of battlefield parks and the role of park management in sustaining grassland birds, we surveyed for 2 declining grassland-breeding species, eastern meadowlark (Sturnella magna) and grasshopper sparrow (Ammodramus savannarum), at 242 points across 4 battlefield parks in Maryland, Virginia, and West Virginia, USA, from 2014–2019 and in 2021. We modeled the effects of park management activities (prescribed fire, agricultural leases, and delayed harvest) and habitat and landscape characteristics on breeding-season occupancy. There was support for the influence of local habitat features, landscape, and management. Breeding-season occupancy of both species was consistently higher in hayfields and pasture than in row crops, and both species responded positively to hay and crop harvest delays intended for grassland bird conservation. Prescribed fire within the past 2 years had a positive effect on occupancy of grasshopper sparrows but did not influence eastern meadowlarks. Eastern meadowlarks responded to land cover at multiple spatial scales that are influenced by land use within and outside the parks. Management activities that maintain the parks' cultural goals, including partnerships between national parks and private agricultural operators, are likely to provide valuable habitat for these 2 obligate grassland birds.     

Neoliberalism and the punitive turn in Southeast Asia and beyond: implications for gender,sexuality, and graduated pluralism

Anthropologists and other scholars have explored the elective affinities between neoliberal globalization and punitive turns in both legal and more expansive cultural-political domains, particularly in Western settings such as the United States, the United Kingdom, and France. This article expands the discussion by engaging these affinities in late modern Southeast Asia, especially the Muslim-majority nations of Malaysia and Indonesia. One goal of the article is to describe and analyse the constriction of pluralism with respect to gender and sexuality, a key feature of the surge in punitiveness in many societies in Southeast Asia and elsewhere. Others include elucidating similarities and differences between trends in Southeast Asia and the new punitiveness we have seen in the United States in recent decades, and highlighting some of the comparative and theoretical implications of my arguments.     

Regional Synthesis of Habitat Relationships in Shrubland Birds

Abstract: Shrubland birds are declining throughout the eastern United States. To manage scrub-shrub habitats for birds, managers need information on avian habitat relationships. Past studies have produced contradictory results in some cases and may be of limited generality because of site- and habitat-specific factors. We studied shrubland birds across 6 habitats in 3 New England states to provide more general information on habitat relationships than has been possible in past studies. Our study sites included all major scrub-shrub habitats in New England: wildlife openings, regenerating clear-cuts, beaver ponds, utility rights-of-way, pitch pine (Pinus rigida) woodlands, and scrub oak (Quercus ilicifolia) barrens and ranged from Connecticut to northern New Hampshire, with research conducted from 2002 to 2007. Using N-mixture models of repeated point counts, we found that 6 of 12 shrubland birds preferred areas with greater shrub cover. An additional 4 species appeared to prefer areas with lower-stature vegetation and greater forb cover. Eight of 10 bird species showed relationships with cover of individual plant species, with Spiraea spp., willows (Salix spp.), alders (Alnus spp.), and invasive exotics being the most important. We recommend that shrubland management for birds focus on providing 2 distinct habitats: 1) areas of tall (>1.5 m) vegetation with abundant shrub cover and 2) areas of lower (<1.5 m) vegetation with abundant forb cover but fewer shrubs.     

Breeding sites and winter site fidelity of Piping Plovers wintering in The Bahamas,a previously unknown major wintering area

Most of the known wintering areas of Piping Plovers (Charadrius melodus) are along the Atlantic and Gulf coasts of the United States and into Mexico, and in the Caribbean. However, 1066 threatened/endangered Piping Plovers were recently found wintering in The Bahamas, an area not previously known to be important for the species. Although representing about 27% of the birds counted during the 2011 International Piping Plover Winter Census, the location of their breeding site(s) was unknown. Thus, our objectives were to determine the location(s) of their breeding site(s) using molecular markers and by tracking banded individuals, identify spring and fall staging sites, and examine site fidelity and survival. We captured and color‐banded 57 birds in January and February 2010 in The Bahamas. Blood samples were also collected for genetic evaluation of the likely subspecies wintering in The Bahamas. Band re‐sightings and DNA analysis revealed that at least 95% of the Piping Plovers wintering in The Bahamas originated on the Atlantic coast of the United States and Canada. Re‐sightings of birds banded in The Bahamas spanned the breeding distribution of the species along the Atlantic coast from Newfoundland to North Carolina. Site fidelity to breeding and wintering sites was high (88–100%). Spring and fall staging sites were located along the Atlantic coast of the United States, with marked birds concentrating in the Carolinas. Our estimate of true survival for the marked birds was 0.71 (95% CI: 0.61–0.80). Our results indicate that more than one third of the Piping Plover population that breeds along the Atlantic coast winters in The Bahamas. By determining the importance of The Bahamas to the Atlantic subspecies of Piping Plovers, future conservation efforts for these populations can be better focused on where they are most needed.     

A Comprehensive Analysis of Small-Passerine Fatalities from Collision with Turbines at Wind Energy Facilities

Small passerines, sometimes referred to as perching birds or songbirds, are the most abundant bird group in the United States (US) and Canada, and the most common among bird fatalities caused by collision with turbines at wind energy facilities. We used data compiled from 116 studies conducted in the US and Canada to estimate the annual rate of small-bird fatalities. It was necessary for us to calculate estimates of small-bird fatality rates from reported all-bird rates for 30% of studies. The remaining 70% of studies provided data on small-bird fatalities. We then adjusted estimates to account for detection bias and loss of carcasses from scavenging. These studies represented about 15% of current operating capacity (megawatts [MW]) for all wind energy facilities in the US and Canada and provided information on 4,975 bird fatalities, of which we estimated 62.5% were small passerines comprising 156 species. For all wind energy facilities currently in operation, we estimated that about 134,000 to 230,000 small-passerine fatalities from collision with wind turbines occur annually, or 2.10 to 3.35 small birds/MW of installed capacity. When adjusted for species composition, this indicates that about 368,000 fatalities for all bird species are caused annually by collisions with wind turbines. Other human-related sources of bird deaths, (e.g., communication towers, buildings [including windows]), and domestic cats) have been estimated to kill millions to billions of birds each year. Compared to continent-wide population estimates, the cumulative mortality rate per year by species was highest for black-throated blue warbler and tree swallow; 0.043% of the entire population of each species was estimated to annually suffer mortality from collisions with turbines. For the eighteen species with the next highest values, this estimate ranged from 0.008% to 0.038%, much lower than rates attributed to collisions with communication towers (1.2% to 9.0% for top twenty species).     

Robustness of ecological niche modeling algorithms for mammals in Guyana

The genetic algorithm for rule-set prediction (GARP) has beensuccessfully used in modeling species' distributions with environmental data forwell-studied birds in the United States and elsewhere. GARP's efficiency hasbeen demonstrated to be robust even with incomplete occurrence and geographicdata. Thorough biological sampling in conjunction with comprehensive geographicinformation, however, is not the norm for many tropical areas where mostbiodiversity occurs. Mammals from Guyana were used as a test of the robustnessof these approaches in a worst-case scenario of uneven sampling combined withcoarse geographic data. The occurrence of species in poorly surveyed regions,such as the Pakaraima Highlands of west-central Guyana, was consistentlyunder-predicted, whereas presence in well-surveyed areas such as thesouthwestern Rupununi was usually correctly predicted. Comparisons of numbersof species and specimens collected also indicate that lowland forests in thesoutheast and coastal forests in the northwest are under-sampled. For robustdistributional predictions in Guyana, more thorough inventories are needed inthese diverse environments.     

Nest sites as limiting resources for cavity‐nesting birds in mature forest ecosystems: a review of the evidence

ABSTRACT Assumptions that populations of cavity‐nesting birds are limited by access to nest sites have largely been based on anecdotal reports or correlative data. Nest‐box‐addition experiments or tree‐cavity‐blocking experiments are potentially rigorous ways to investigate how densities of breeding birds are affected by access to nest cavities. Experimental evidence indicates that natural tree holes are limited in human‐altered landscapes, but the possibility that cavity nests are limited in old growth (unmanaged) forests is less clear. I reviewed 31 nest‐cavity‐removal or addition experiments conducted with 20 species of cavity‐nesting birds in mature forests. Of these 31 experiments conducted with a variety of different species of birds, only 19% reported statistically significant changes in breeding densities. However, none of these studies included data about the reproductive history of individuals colonizing the boxes (i.e., whether birds using the boxes would have otherwise been floaters or that birds excluded from blocked cavities on the plots did not simply move elsewhere), so they provided no strong evidence that the number of breeding pairs was limited by availability of nest sites at the population scale. Although some studies indicate that nest sites are limited at local (plot) scales in old growth forests, there is still little empirical evidence for nest‐site limitation at the population‐ and landscape‐level in mature, unmanaged forests. I review the challenges in designing and interpreting box‐addition experiments and highlight the main gaps in knowledge that should be targeted in the future.     

Connectivity in piping plovers: Do breeding populations have distinct winter distributions?

Resightings of uniquely marked birds from 2001 to 2008 were used to determine winter distributions of 4 breeding populations of a species at risk, the piping plover (Charadrius melodus). Although considerable overlap exists, a distinct pattern in winter distributions was evident. Birds originating from eastern Canada wintered farthest north compared to other populations. Most individuals from the United States Great Lakes were found in South Carolina and Georgia in winter, whereas birds from eastern Canada were found primarily in North Carolina. Although the great majority of birds marked in Prairie Canada were observed wintering in Texas, particularly southern Texas, breeding plovers from the United States Great Plains were more widely distributed on the gulf coast from Florida to Texas. Very few large-scale movements of individuals in winter were reported either within or between years. This study highlights the significance of geographic regions for eastern Canada, the United States Great Lakes, the United States Great Plains, and Prairie Canada populations, and demonstrates relatively high winter site fidelity. This information will help focus conservation efforts for specific breeding populations during the winter. © 2011 The Wildlife Society.     

Avian Migrants Facilitate Invasions of Neotropical Ticks and Tick-Borne Pathogens into the United States

Migratory birds have the potential to transport exotic vectors and pathogens of human and animal health importance across vast distances. We systematically examined birds that recently migrated to the United States from the Neotropics for ticks. We screened both ticks and birds for tick-borne pathogens, including Rickettsia species and Borrelia burgdorferi. Over two spring seasons (2013 and 2014), 3.56% of birds (n = 3,844) representing 42.35% of the species examined (n = 85) were infested by ticks. Ground-foraging birds with reduced fuel stores were most commonly infested. Eight tick species were identified, including seven in the genus Amblyomma, of which only Amblyomma maculatum/Amblyomma triste is known to be established in the United States. Most ticks on birds (67%) were neotropical species with ranges in Central and South America. Additionally, a single Ixodes genus tick was detected. A total of 29% of the ticks (n = 137) and no avian blood samples (n = 100) were positive for infection with Rickettsia species, including Rickettsia parkeri, an emerging cause of spotted fever in humans in the southern United States, a species in the group of Rickettsia monacensis, and uncharacterized species and endosymbionts of unknown pathogenicity. No avian tick or blood samples tested positive for B. burgdorferi, the etiologic agent of Lyme disease. An extrapolation of our findings suggests that anywhere from 4 to 39 million exotic neotropical ticks are transported to the United States annually on migratory songbirds, with uncertain consequences for human and animal health if the current barriers to their establishment and spread are overcome.     

Aquatic bird distributions in Mexico: designing conservation approaches quantitatively

The aquatic birds of Mexico include both a rich fauna of residents and a significant proportion of migratory species that breed in Canada and the United States, yet their distribution and richness patterns remain poorly known. We developed a detailed database of occurrences, and estimated distributions using niche modeling interpolations for 134 species associated with wetlands. Validations of the resulting maps indicated that the niche-modeling approach yields a useful picture of aquatic bird species distributions in the country. Richness patterns among aquatic birds differ from those for landbirds: species richness is concentrated in coastal areas, but endemism is focused in the Transvolcanic Belt and the Altiplano. Place prioritization exercises identified sets of areas that would maximize the protection of this diversity.     

Genetic studies facilitated management decisions on the invasion of the ruddy duck in Europe

The ruddy duck (Oxyura jamaicensis), a stifftail native to the Americas, was introduced to the UK in the 1950s and has since been recorded in 22 western Palearctic countries. By 2000, the UK population peaked at nearly 6,000 individuals. In 1991, hybridisation with the native and globally threatened (IUCN Endangered) white-headed duck (Oxyura leucocephala), a stifftail restricted to the Mediterranean and Asia, was recorded in Spain and culling of hybrids and ruddy ducks began. Here we report on a series of genetic studies that have enabled and supported management decisions to the benefit of the white-headed duck. First, genetic data confirmed that these are two distinct species, each of which is more closely related to other stifftail species. Second, molecular studies indicated that ruddy ducks in Spain, Iceland and elsewhere in Europe were of captive origin and not descendants from vagrants from their native North America. Third, genetic methods were used to distinguish among different hybrid generations in Spain and detected no ruddy duck introgression in birds identified morphologically as white-headed ducks. Collectively, these results supported management decisions to eradicate ruddy ducks from Europe. Subsequently, a control programme reduced the UK population by over 95 % by 2010, and the arrival of ruddy ducks to Spain decreased from 21 birds in 2003 to two sightings in 2010–2011. However, increased efforts to control small ruddy duck populations elsewhere in Europe and Morocco are still required to ensure conservation of the white-headed duck. This case of invasion by hybridization demonstrates that successful control is feasible given early detection followed by a rapid response plan; it also shows the contribution of research to management and that to guarantee the conservation of an endangered native species action may be required in countries outside its distribution range.     

Was a ‘hyperdisease’ responsible for the late Pleistocene megafaunal extinction?

Numerous hypotheses have been proposed to explain the end Pleistocene extinction of large bodied mammals. The disease hypothesis attributes the extinction to the arrival of a novel ‘hyperdisease’ brought by immigrating aboriginal humans. However, until West Nile virus (WNV) invaded the United States, no known disease met the criteria of a hyperdisease. We evaluate the disease hypothesis using WNV in the United States as a model system. We show that WNV is size‐biased in its infection of North America birds, but is unlikely to result in an extinction similar to that of the end Pleistocene. WNV infects birds more uniformly across the body size spectrum than extinctions did across mammals and is not size‐biased within orders. Our study explores the potential impact of WNV on bird populations and provides no support for disease as a causal mechanism for the end Pleistocene megafaunal extinction.     

Large-Scale Avian Influenza Surveillance in Wild Birds throughout the United States

Avian influenza is a viral disease that primarily infects wild and domestic birds, but it also can be transmitted to a variety of mammals. In 2006, the United States of America Departments of Agriculture and Interior designed a large-scale, interagency surveillance effort that sought to determine if highly pathogenic avian influenza viruses were present in wild bird populations within the United States of America. This program, combined with the Canadian and Mexican surveillance programs, represented the largest, coordinated wildlife disease surveillance program ever implemented. Here we analyze data from 197,885 samples that were collected from over 200 wild bird species. While the initial motivation for surveillance focused on highly pathogenic avian influenza, the scale of the data provided unprecedented information on the ecology of avian influenza viruses in the United States, avian influenza virus host associations, and avian influenza prevalence in wild birds over time. Ultimately, significant advances in our knowledge of avian influenza will depend on both large-scale surveillance efforts and on focused research studies.     

Prioritizing Avian Species for Their Risk of Population-Level Consequences from Wind Energy Development

Recent growth in the wind energy industry has increased concerns about its impacts on wildlife populations. Direct impacts of wind energy include bird and bat collisions with turbines whereas indirect impacts include changes in wildlife habitat and behavior. Although many species may withstand these effects, species that are long-lived with low rates of reproduction, have specialized habitat preferences, or are attracted to turbines may be more prone to declines in population abundance. We developed a prioritization system to identify the avian species most likely to experience population declines from wind facilities based on their current conservation status and their expected risk from turbines. We developed 3 metrics of turbine risk that incorporate data on collision fatalities at wind facilities, population size, life history, species’ distributions relative to turbine locations, number of suitable habitat types, and species’ conservation status. We calculated at least 1 measure of turbine risk for 428 avian species that breed in the United States. We then simulated 100,000 random sets of cutoff criteria (i.e., the metric values used to assign species to different priority categories) for each turbine risk metric and for conservation status. For each set of criteria, we assigned each species a priority score and calculated the average priority score across all sets of criteria. Our prioritization system highlights both species that could potentially experience population decline caused by wind energy and species at low risk of population decline. For instance, several birds of prey, such as the long-eared owl, ferruginous hawk, Swainson’s hawk, and golden eagle, were at relatively high risk of population decline across a wide variety of cutoff values, whereas many passerines were at relatively low risk of decline. This prioritization system is a first step that will help researchers, conservationists, managers, and industry target future study and management activity.     

Intraspecific genetic analysis of the summer tanager Piranga rubra: implications for species limits and conservation

The summer tanager Piranga rubra is a Neotropical migrant that has experienced noted declines in the southwestern United States caused by extensive habitat loss of native riparian woodlands. This species is composed of two morphologically and behaviorally distinct taxa that traditionally have been recognized as subspecies, each occupying unique habitats in the southern part of North America. Genetic analyses of intraspecific variation are important in studies of threatened or endangered species because they can indicate whether smaller management units exist below the species level and they also provide estimates of within population variability. Using a mitochondrial DNA marker, the intraspecific genetic variation of this species is explored to determine whether the morphologically and behaviorally distinct subspecies are also genetically unique. By using traditional phylogenetic methods and building haplotype networks, results from this study indicate that the subspecies represent two phylogenetic species and should be managed as separate units. In addition, the level of gene flow among geographically isolated populations of the western subspecies is explored using Nested Clade Phylogeographic Analysis and population genetic tests. These analyses show that populations are genetically diverse and that haplotypes are shared across populations. Newly colonized populations are as diverse as older populations. This suggests that as habitat degrades in traditional breeding areas of the summer tanager, if suitable habitat elsewhere becomes available for new populations, these new colonies should be genetically diverse.     

Survival,fidelity, and recovery rates of white-winged doves in Texas

Management of migratory birds at the national level has historically relied on regulatory boundaries for definition of harvest restrictions and estimation of demographic parameters. Most species of migratory game birds are not expanding their ranges, so migratory corridors are approximately fixed. White-winged doves (Zenaida asiatica), however, have undergone significant variation in population structure with marked range expansion occurring in Texas, and range contraction in Arizona, during the last 30 years. Because >85% of white-winged dove harvest in the United States (approx. 1.3 million annually) now occurs in Texas, information on vital rates of expanding white-winged dove populations is necessary for informed management. We used band recovery and mark–recapture data to investigate variation in survival and harvest across 3 geographic strata for white-winged doves banded in the pre-hunting season in Texas during 2007–2010. We banded 60,742 white-winged doves, recovered 2,458 bands via harvest reporting, and recaptured 455 known-age birds between 2007 and 2010. The best supporting model found some evidence for geographic differences in survival rates among strata (A–C) in both hatch-year (juvenile; A = 0.205 [SE = 0.0476], B = 0.213 [SE = 0.0278], C = 0.364 [SE = 0.0254]) and after-hatch year (adult; A = 0.483 [SE = 0.0775], B = 0.465 [SE = 0.0366], C = 0.538 [SE = 0.251]) birds. White-winged doves had a low probability of moving among strata (0.009) or being recaptured (0.002) across all strata. Harvest recovery rates were concordant with estimates for other dove species, but were variable across geographic strata. Based on our results, harvest management strategies for white-winged doves in Texas and elsewhere should consider differences in population vital rates among geographic strata. © 2012 The Wildlife Society.