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A wing and a prayer : the race to save our vanishing birds
\"In the fall of 2019, headlines delivered shocking news: nearly three billion birds in North America have vanished over the past fifty years. No species has been spared, from the most delicate jeweled hummingbirds to scrappy black crows, from a rainbow of warblers to common birds such as owls and sparrows. For the past year, veteran journalists Anders and Beverly Gyllenhaal traveled more than 25,000 miles across the Americas, chronicling costly experiments, contentious politics, and new technologies to save our beloved birds from the brink of extinction. Through this compelling drama, A Wing and a Prayer offers hope and an urgent call to action: Birds are dying at an unprecedented pace. But there are encouraging breakthroughs across the hemisphere and still time to change course, if we act quickly\"-- Provided by publisher
Book
Impacts of the Northwest Forest Plan on forest composition and bird populations
The Northwest Forest Plan (NWFP) initiated one of the most sweeping changes to forest management in the world, affecting 10 million hectares of federal land. The NWFP is a science-based plan incorporating monitoring and adaptive management and provides a unique opportunity to evaluate the influence of policy. We used >25 years of region-wide bird surveys, forest data, and landownership maps to test this policy’s effect on biodiversity. Clearcutting decreased rapidly, and we expected populations of olderforest–associated birds to stabilize on federal land, but to continue declining on private industrial lands where clearcutting continued. In contrast, we expected declines in early-seral–associated species on federal land because of reduced anthropogenic disturbance since the NWFP. Bayesian hierarchical models revealed that bird species’ population trends tracked changes in forest composition. However, against our expectations, declines of birds associated with older forests accelerated. These declines are partly explained by losses of older forests due to fire on federal land and continued clearcutting elsewhere. Indeed, the NWFP anticipated that reversing declines of older forests would take time. Overall, the early-seral ecosystem area was stable, but declined in two ecoregions—the Coast Range and Cascades—along with early-seral bird populations. Although the NWFP halted clearcutting on federal land, this has so far been insufficient to reverse declines in older-forest–associated bird populations. These findings underscore the importance of continuing to prioritize older forests under the NWFP and ensuring that the recently proposed creation of early-seral ecosystems does not impede the conservation and development of older-forest structure.
Journal Article
Decomposing trends in Swedish bird populations using generalized additive mixed models
1. Estimating trends of populations distributed across wide areas is important for conservation and management of animals. Surveys in the form of annually repeated counts across a number of sites are used in many monitoring programmes, and from these, nonlinear trends may be estimated using generalized additive models (GAM). 2. I use generalized additive mixed models (GAMM) to decompose population change into a long-term, smooth, trend component and a component for short-term fluctuations. The longterm population trend is modelled as a smooth function of time and short-term fluctuations as temporal random effects. The methods are applied to analyse trends in goldcrest and greenfinch populations in Sweden using data from the Swedish Breeding Bird Survey. I use simulations to investigate statistical properties of the model. 3. The model separates short-term fluctuations from longer term population change. Depending on the amount of noise in the population fluctuations, estimated long-term trends can differ markedly from estimates based on standard GAMs. For the goldcrest with wide among-year fluctuations, trends estimated with GAMs suggest that the population has in recent years recovered from a decline. When filtering out, short-term fluctuations analyses suggest that the population has been in steady decline since the beginning of the survey. 4. Simulations suggest that trend estimation using the GAMM model reduces spurious detection of long-term population change found with estimates from a GAM model, but gives similar mean square errors. The simulations therefore suggest that the GAMM model, which decomposes population change, estimates uncertainty of long-term trends more accurately at little cost in detecting them. 5. Policy implications. Filtering out short-term fluctuations in the estimation of long-term smooth trends using temporal random effects in a generalized additive mixed model provides more robust inference about the long-term trends compared to when such random effects are not used. This can have profound effects on management decisions, as illustrated in an example for goldcrest in the Swedish breeding bird survey. In the example, if temporal random effects were not used, red listing would be highly influenced by the specific year in which it was done. When temporal random effects are used, red listing is stable over time. The methods are available in an R-package, pop trend.
Journal Article
How do en route events around the Gulf of Mexico influence migratory landbird populations?
Habitats around the Gulf of Mexico (GOM) provide critical resources for Nearctic–Neotropical migratory landbirds, the majority of which travel across or around the GOM every spring and fall as they migrate between temperate breeding grounds in North America and tropical wintering grounds in the Caribbean and Central and South America. At the same time, ecosystems in the GOM are changing rapidly, with unknown consequences for migratory landbird populations, many of which are experiencing population declines. In general, the extent to which events encountered en route limit migratory bird populations is not well understood. At the same time, information from weather surveillance radar, stable isotopes, tracking, eBird, and genetic datasets is increasingly available to address many of the unanswered questions about bird populations that migrate through stopover and airspace habitats in the GOM. We review the state of the science and identify key research needs to understand the impacts of en route events around the GOM region on populations of intercontinental landbird migrants that breed in North America, including: (1) distribution, timing, and habitat associations; (2) habitat characteristics and quality; (3) migratory connectivity; and (4) threats to and current conservation status of airspace and stopover habitats. Finally, we also call for the development of unified and comprehensive long-term monitoring guidelines and international partnerships to advance our understanding of the role of habitats around the GOM in supporting migratory landbird populations moving between temperate breeding grounds and wintering grounds in Mexico, Central and South America, and the Caribbean.
Journal Article
Finding a dove for Gramps
As a boy and his mother participate in the annual bird count, he misses his grandfather, who went south for the winter, and watches especially for Gramps' favorite bird. Includes facts about the history and purpose of the Christmas Bird Count, how to participate, and a bird checklist.
Book
The role of the North American Breeding Bird Survey in conservation
The North American Breeding Bird Survey (BBS) was established in 1966 in response to a lack of quantitative data on changes in the populations of many bird species at a continental scale, especially songbirds. The BBS now provides the most reliable regional and continental trends and annual indices of abundance available for >500 bird species. This paper reviews some of the ways in which BBS data have contributed to bird conservation in North America over the past 50 yr, and highlights future program enhancement opportunities. BBS data have contributed to the listing of species under the Canadian Species at Risk Act and, in a few cases, have informed species assessments under the U.S. Endangered Species Act. By raising awareness of population changes, the BBS has helped to motivate bird conservation efforts through the creation of Partners in Flight. BBS data have been used to determine priority species and locations for conservation action at regional and national scales through Bird Conservation Region strategies and Joint Ventures. Data from the BBS have provided the quantitative foundation for North American State of the Birds reports, and have informed the public with regard to environmental health through multiple indicators, such as the Canadian Environmental Sustainability Indicators and the U.S. Environmental Protection Agency's Report on the Environment. BBS data have been analyzed with other data (e.g., environmental, land cover, and demographic) to evaluate potential drivers of population change, which have then informed conservation actions. In a few cases, BBS data have contributed to the evaluation of management actions, including informing the management of Mourning Doves (Zenaida macroura), Wood Ducks (Aix sponsa), and Golden Eagles (Aquila chrysaetos). Improving geographic coverage in northern Canada and in Mexico, improving the analytical approaches required to integrate data from other sources and to address variation in detectability, and completing the database, by adding historical bird data at each point count location and pinpointing the current point count locations would further enhance the survey's value.
Journal Article
Ornithological characterisation of the natural habitats’s Lake Dayet Er Roumi (Khemisset, Morocco)
The permanent natural lake located in the Dayet Er-Roumi lake ecosystem (N 33°74’ - W 6°19’) is a Site of Biological and Ecological Interest (SIBE) that is unique in a semi-continental region. This site has a distinct sub-humid microclimate, in marked contrast to the vast semi-arid zone that surrounds it. Located 15 kilometres south of the town of Khémisset, the lake is subject to significant human pressure due to its ease of access, its importance to local communities and its significant biological value. The overall aim of this study is to analyse the Dayet Er-Roumi lake ecosystem, focusing on the site’s natural habitats and their interactions with the bird population. The study aims to provide an in-depth understanding of the environmental health and biodiversity of the lake, given the significant human pressure exerted on it. The research took place during the 2020-2021 campaign, with regular weekly analyses and observations. Analysis of the ecology of bird populations and their natural environments at Lake Dayet Er-Roumi revealed a gradual deterioration in the natural habitats of the lake system. The latter includes wetland habitats such as surface water, the aquatic bed, emergents, trees and shrubs, woodlands and non-vegetative areas, as well as non-wetland habitats such as agricultural fields and residential areas. This alteration has a negative impact on the distribution of bird populations, whether sedentary or migratory. A total of 45 species were recorded during the study, but it is important to note that 4 of them have a dual status, with the following numbers: sedentary breeders (n=1), sedentary non-breeders (n=19), winterers (n=17), migratory passage birds (n=10), and occasional visitors (n=3).
Journal Article