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At least 973 records · Page 54Linked to original sources

USGS2022

Estimating reproductive and juvenile survival rates when offspring ages are uncertain: A novel multievent mark-resight model with beluga whale case study

Understanding the survival and reproductive rates of a population is critical to determining its long-term dynamics and viability. Mark-resight models are often used to estimate these demographic rates, but estimation of survival and reproductive rates is challenging, especially for wide-ranging, patchily distributed, or cryptic species. In particular, existing mark-resight models cannot accommodate data from populations in which offspring remain with parents for multiple years, are not always detected, and cannot be aged with certainty. Here we describe a Bayesian multievent mark-resight modelling framework that uses all available adult and adult-offspring sightings (including sightings with older offspring of uncertain age) to estimate reproductive rates and survival rates of adults and juveniles. We extend existing multievent mark-resight models that typically only incorporate adult breeding state uncertainty by additionally accounting for age uncertainty in unmarked offspring and uncertainty in the duration of the mother-offspring association. We describe our model in general terms and with a simple illustrative example, then apply it in a more complex empirical setting using 13 years of photo-ID data from a critically endangered population of beluga whales Delphinapterus leucas . We evaluated model performance using simulated data under a range of sample sizes, and adult and offspring detection rates. Applying our model to the beluga data yielded precise estimates for all demographic rates of interest (despite substantial uncertainty in calf ages), including nonbreeder survival and reproductive rates lower than in other beluga populations. Simulations suggested our model yields asymptotically unbiased parameter estimates with good precision and low bias even with moderate sample sizes and detection rates. This work represents an important new development in multievent mark-resight modelling, allowing estimation of reproductive and juvenile survival rates for populations with extended adult—offspring associations and uncertain offspring ages (e.g. some marine mammals, elephants, bears, great apes, bats and birds). Our model facilitated estimation of robust demographic rates for an endangered beluga population that were previously inestimable (e.g. nonbreeder and juvenile survival, reproductive rate) and that will yield new insights into this population's continued decline.

Methods in Ecology and Evolution↗

USGS2018

Extinction risk and conservation options for Maui Parrotbill, an endangered Hawaiian honeycreeper

Extinction rates for island birds around the world have been historically high. For forest passerines, the Hawaiian archipelago has suffered some of the highest extinction rates and reintroduction is a conservation tool that can be used to prevent the extinction of some of the remaining endangered species. Population viability analyses can be used to assess risks to vulnerable populations and evaluate the relative benefits of conservation strategies. Here we present a population viability analysis to assess the long-term viability for Maui parrotbill(s) (Kiwikiu) Pseudonestor xanthophrys, a federally endangered passerine on the Hawaiian island of Maui. Contrary to indications from population monitoring, our results indicate Maui parrotbills may be unlikely to persist beyond 25 years. Our modeling suggests female mortality as a primary factor driving this decline. To evaluate and compare management options involving captive rearing and translocation strategies we made a female-only stage-structured, meta-population simulation model. Due to the low reproductive potential of Maui parrotbills in captivity, the number of individuals (~ 20% of the global population) needed to source a reintroduction solely from captive reared birds is unrealistic. A reintroduction strategy that incorporates a minimal contribution from captivity and instead translocates mostly wild individuals was found to be the most feasible management option. Habitat is being restored on leeward east Maui, which may provide more favorable climate and habitat conditions and promote increased reproductive output. Our model provides managers with benchmarks for fecundity and survival needed to ensure reintroduction success, and highlights the importance of establishing a new population in potentially favorable habitat to ensure long-term persistence.

Journal of Fish and Wildlife Management↗

USGS2014

Birds of a feather

Greater sage-grouse ( Centrocercus urophasiunus , hereafter sage-grouse) are broadly distributed, occupy a diversity of sagebrush habitats, and face multiple threats. As a result of these threats, sage-grouse populations are declining and are now absent from almost one-half of their estimated range prior to Euro-American settlement. The risks to sage-grouse are significant enough to merit candidate status for this species for listing under the U.S. Endangered Species Act (Federal Register Notice, March 5, 2010). According to this decision by the U.S. Fish and Wildlife Service in 2010, population and habitat fragmentation coupled with lack of regulatory mechanisms warranted listing, although implementation of actions has been precluded by other priorities. Candidate status for listing under the Endangered Species Act and possible regulatory action in the near future provide strong motivation to better understand the dynamics of sage-grouse populations and their habitat requirements. The general approach currently taken by managers focuses on maintaining or enhancing sage-grouse populations across their distribution in regions containing the highest densities of breeding birds and their important seasonal habitats, also known as priority areas for conservation (PACs). The rationale behind this approach is that it permits limited resources to be applied in regions that have the greatest potential to benefit the largest proportion of sage-grouse. Development and other forms of land use can then proceed under standard regulations in areas outside PACs. Implementation of this approach requires detailed information about habitat, connections among sage-grouse populations, and approaches to restore and maintain sagebrush. These are important topics of study by the U.S. Geological Survey (USGS) and its research partners.

California;Idaho;Nevada;Oregon;Utah;Washington↗

USGS2014

Interactive effects of climate change with nutrients, mercury, and freshwater acidification on key taxa in the North Atlantic Landscape Conservation Cooperative region

The North Atlantic Landscape Conservation Cooperative LCC (NA LCC) is a public–private partnership that provides information to support conservation decisions that may be affected by global climate change (GCC) and other threats. The NA LCC region extends from southeast Virginia to the Canadian Maritime Provinces. Within this region, the US National Climate Assessment documented increases in air temperature, total precipitation, frequency of heavy precipitation events, and rising sea level, and predicted more drastic changes. Here, we synthesize literature on the effects of GCC interacting with selected contaminant, nutrient, and environmental processes to adversely affect natural resources within this region. Using a case study approach, we focused on 3 stressors with sufficient NA LCC region-specific information for an informed discussion. We describe GCC interactions with a contaminant (Hg) and 2 complex environmental phenomena—freshwater acidification and eutrophication. We also prepared taxa case studies on GCC- and GCC-contaminant/nutrient/process effects on amphibians and freshwater mussels. Several avian species of high conservation concern have blood Hg concentrations that have been associated with reduced nesting success. Freshwater acidification has adversely affected terrestrial and aquatic ecosystems in the Adirondacks and other areas of the region that are slowly recovering due to decreased emissions of N and sulfur oxides. Eutrophication in many estuaries within the region is projected to increase from greater storm runoff and less denitrification in riparian wetlands. Estuarine hypoxia may be exacerbated by increased stratification. Elevated water temperature favors algal species that produce harmful algal blooms (HABs). In several of the region's estuaries, HABs have been associated with bird die-offs. In the NA LCC region, amphibian populations appear to be declining. Some species may be adversely affected by GCC through higher temperatures and more frequent droughts. GCC may affect freshwater mussel populations via altered stream temperatures and increased sediment loading during heavy storms. Freshwater mussels are sensitive to un-ionized ammonia that more toxic at higher temperatures. We recommend studying the interactive effects of GCC on generation and bioavailability of methylmercury and how GCC-driven shifts in bird species distributions will affect avian exposure to methylmercury. Research is needed on how decreases in acid deposition concurrent with GCC will alter the structure and function of sensitive watersheds and surface waters. Studies are needed to determine how GCC will affect HABs and avian disease, and how more severe and extensive hypoxia will affect fish and shellfish populations. Regarding amphibians, we suggest research on 1) thermal tolerance and moisture requirements of species of concern, 2) effects of multiple stressors (temperature, desiccation, contaminants, nutrients), and 3) approaches to mitigate impacts of increased temperature and seasonal drought. We recommend studies to assess which mussel species and populations are vulnerable and which are resilient to rising stream temperatures, hydrological shifts, and ionic pollutants, all of which are influenced by GCC.

Chesapeake Bay↗

USGS2005

A fresh look at the taxonomy of midcontinental sandhill cranes

The midcontinental population of sandhill crane ( Grus canadensis ) includes about 500,000 birds and provides valuable recreational crane-watching and hunting opportunities in Canada and the United States. It comprises three subspecies, one of which ( G. c. rowani ) was of uncertain taxonomic status and another of which ( G. c. tabida ) merited protection from excessive harvest due to its small population size. We obtained measurements of cranes used by Johnson and Stewart (1973) and additional crane specimens to 1) evaluate the subspecies designation of midcontinental sandhill cranes and 2) to seek improved methods for classifying cranes from selected measurements. We found that the three named subspecies are in fact morphologically distinct, although there is a general gradient of smaller birds breeding in the far north to larger birds breeding at more southerly latitudes. We were not able to find better ways of identifying subspecies; in particular we could not find a reliable method that did not require knowledge of the sex of an individual crane.

Conference Paper↗

USGS2009

Spatial and temporal variation in climate change: A bird’s eye view

Recent changes in global climate have dramatically altered worldwide temperatures and the corresponding timing of seasonal climate conditions. Recognizing the degree to which species respond to changing climates is therefore an area of increasing conservation concern as species that are unable to respond face increased risk of extinction. Here we examine spatial and temporal heterogeneity in the rate of climate change across western North America and discuss the potential for conditions to arise that may limit the ability of western migratory birds to adapt to changing climates. Based on 52 years of climate data, we show that changes in temperature and precipitation differ significantly between spring migration habitats in the desert southwest and breeding habitats throughout western North America. Such differences may ultimately increase costs to individual birds and thereby threaten the long-term population viability of many species.

Climatic Change↗

USGS2015

Range-wide wetland associations of the King Rail: A multi-scale approach

King Rail populations have declined and identifying wetland features that influence King Rail occupancy can help prevent further population declines. We integrated continent-wide marsh bird survey data with spatial wetland data from the National Wetland Inventory (NWI) to examine wetland features that influenced King Rail occupancy throughout the species’ range. We analyzed wetland data at 7 spatial scales to examine the scale(s) at which 68 wetland features were most strongly related to King Rail occupancy. Occupancy was most strongly associated with estuarine features and brackish and tidal saltwater regimes. King Rail occupancy was positively associated with emergent and scrub-shrub wetlands and negatively associated with forested wetlands. The best spatial scale for assessing King Rail occupancy differed among wetland features; we could not identify one spatial scale (among all wetland features) that best explained variation in occupancy. Future research on King Rail habitat that includes multiple spatial scales is more likely to identify the suite of features that influence occupancy. Our results indicate that NWI data may be useful for predicting occupancy based on broad habitat features across the King Rail’s range, which may help inform management decisions for this and other wetland-dependent birds.

Wetlands↗

USGS2005

A mechanistic link between chick diet and decline in seabirds?

A climatic regime shift during the mid-1970s in the North Pacific resulted in decreased availability of lipidrich fish to seabirds and was followed by a dramatic decline in number of kittiwakes breeding on the Pribilof Islands. Although production of chicks in the mid-1970s was adequate to sustain kittiwake populations in the early 1980s, the disappearance of birds from breeding colonies apparently exceeded recruitment. No mechanism has been proposed to explain why recruitment would differ among fledglings fed lipid-rich or lipid-poor fish during development. Here we show that diets low in lipids induce nutritional stress and impair cognitive abilities in young red-legged kittiwakes, Rissa brevirostris. Specifically, growth retardation, increased secretion of stress hormones and inferior ability to associate food distribution with visual cues were observed in individuals fed lipid-poor diets. We conclude that lipid-poor diets during development affect the quality of young seabirds, which is likely to result in their increased mortality and low recruitment. ?? 2005 The Royal Society.

Proceedings of the Royal Society B: Biological Sci↗

USGS2021

Global political responsibility for the conservation of albatrosses and large petrels

Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm.

Science Advances↗

USGS2014

A comprehensive analysis of small-passerine fatalities from collisions 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 39 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).

PLoS ONE↗

USGS1993

Body composition of wintering canvasbacks in Louisiana: Dominance and survival implications

I studied effects of sex, age, and month on body mass and composition of Canvasbacks ( Aythya valisineria ) at Catahoula Lake (CL) and the Mississippi River Delta (MRD), Louisiana, in winter 1987-1988. Size-adjusted body mass and fat varied by age, month, and site. Fat levels in immatures were greater at MRD than at CL, but changed similarly at both sites. Adults at MRD were also fatter than those at CL in early winter, especially in December, but fat levels of all birds increased from early to late winter and were equivalent by late winter. Body protein adjusted for structural size varied by age, month, and site, and sex, month, and site. Protein levels by site were higher in adults and males than in immatures and females, but sex- and age-related differences averaged <11 g (5%). Changes in size-adjusted leg muscle protein (index of feeding activity) and body fat were positively associated. This relation (my measure of feeding efficiency) was not affected by sex or age of Canvasbacks, implying that all birds at CL or MRD fed at similar efficiencies by month. At both sites, females were fatter than males; thus, although males were larger and potentially dominant to females, it appears that females were not disadvantaged in their acquisition of nutrients during the year of study. Body mass of CL and MRD birds in winter 1987-1988 was greater than that of Canvasbacks wintering elsewhere. If overwinter and annual survival of Canvasbacks are related to their relative body mass during winter, then survival probabilities of CL and MRD birds may be high compared to other wintering populations.

Louisiana↗

USGS1990

[Book review] Ospreys: A natural and unnatural history

The Osprey ( Pandion haliaetus ) is now arguably the world's best known bird of prey. The DDT-related Osprey population crash in the northeastern United States resulted in an unparalleled amount of research during the last 20 years. In 1969, when I published my first paper on Ospreys in The Auk, there were only three or four osprey papers of consequence in the United States, plus an important paper on Swedish Ospreys, which hardly compares to the nearly 300 papers (the great majority dealing with Ospreys) cited by Poole in his book. Based on his detailed investigations in eastern North America and the literature from throughout the world, Poole wrote a book with perfect timing. A synthesis of the massive literature on this species was needed, and judging from the bio- logical soundness, completeness, and clear writing style, Poole was the proper person to write the book. Of course it is one aim to prepare a synthesis but, in addition, Poole carefully points out potential biases in data, gaps in information, and needs for further research. The book is both informative, and points out research problems for the next generation of Osprey investigators.

The Auk↗

USGS1975

Distribution and density of bird species hazardous to aircraft

Only in the past 5 years has it become feasible to map the relative abundance of North American birds. Two programs presently under way and a third that is in the experimental phase are making possible the up-to-date mapping of abundance as well as distribution. A fourth program that has been used successfully in Europe and on a small scale in parts of North America yields detailed information on breeding distribution. The Breeding Bird Survey, sponsored by the U.S. Bureau of Sport Fisheries and Wildlife and the Canadian Wildlife Service, involves 2,000 randomly distributed roadside counts that are conducted during the height of the breeding season in all U.S. States and Canadian Provinces. Observations of approximately 1.4 million birds per year are entered on magnetic tape and subsequently used both for statistical analysis of population trends and for computer mapping of distribution and abundance. The National Audubon Society's Christmas Bird Count is conducted in about 1,000 circles, each 15 miles (24 km) in diameter, in the latter half of December. Raw data for past years have been published in voluminous reports, but not in a form for ready analysis. Under a contract between the U.S. Air Force and the U. S. Bureau of Sport Fisheries and Wildlife (in cooperation with the National Audubon Society), preliminary maps showing distribution and abundance of selected species that are potential hazards to aircraft are presently being mapped and prepared for publication. The Winter Bird Survey, which is in its fifth season of experimental study in a limited area in Central Maryland, may ultimately replace the Christmas Bird Count source. This Survey consists of a standardized 8-kilometer (5-mile) route covered uniformly once a year during midwinter. Bird Atlas programs, which map distribution but not abundance, are well established in Europe and are gaining interest in America

Book chapter↗

USGS1985

Recent changes in the ranges of North American birds

The North American Breeding Bird Survey has provided an annual index of population change since 1966. About 2400 randomly distributed roadside routes of 50 three-minute stops each provide the basic data for computer analysis. One of the reports produced shows the percentage of routes on which each species is encountered in each state and each Canadian province. This percentage is used to show expansion and contraction of breeding range and also important changes in frequency of encounter within various portions of the range of each species. Most of the recent changes in range fall in one of these 7 categories: (1) introduced species; (2) species given special protection; (3) species benefiting from artificial feeding in winter; (4) species taking advantage of shelterbelts; (5) species nesting on large highway bridges and dams; (6) species that feed on grain lost during mechanical harvesting: and (7) species losing habitat as a result of urban expansion. Examples of each category are supported by changes in the rate of encounter.

Book chapter↗

USGS1984

DDE in birds' eggs: Comparisons of two methods for estimating critical levels

The sample egg technique and eggshell thickness-residue regression analysis were comparatively evaluated as tools in estimating critical levels of DDE in birds? eggs that seriously affect reproductive successa nd population starts....In comparing critical values of DDE that were derived from the two methods, the estimates were lower using the sample egg technique for both the Brown Pelican (3 ?g/g vs 8 ?g/g) and the Black-crowned Night-Heron (12?g/g/ vs 54 ?g/g) assuming a critical value of eggshell thinning at 20%....Extension of the regression line beyond the eggshell thickness-DDE residue data base is likely to result in spurious critical values of DDE. When sufficient thickness and residue data are available for estimating critical values of DDE from the regression equation, the estimates are meaningful but are likely to be inflated because adverse effects unrelated to eggshell thinning such as parental behavior and embryotoxicity unrelated to eggshell deficiencies are not taken into account.....Establishing critical levels of pollutants in eggs and tissues is a necessary procedure in assessing effects of these chemicals on individuals and populations of sensitive species. There are inherent difficulties in quantifying the effects of any pollutant on population trends and declines in productivity. The sample egg technique is apparently a more sensitive method for estimating critical levels of DDE, but some subjective interpretation is required for results obtained by both methods.

The Wilson Bulletin↗

USGS2023

Land cover differentially affects abundance of common and rare birds

While rare species are vulnerable to global change, large declines in common species (i.e., those with large population sizes, large geographic distributions, and/or that are habitat generalists) also are of conservation concern. Understanding if and how commonness mediates species' responses to global change, including land cover change, can help guide conservation strategies. We explored avian population responses to land cover change along a gradient from common to rare species using avian data from the North American Breeding Bird Survey (BBS) and land cover data from the National Land Cover Database for the conterminous United States. Specifically, we used generalized linear mixed effects models to ask if species' commonness affected the relationship between land cover and counts, using the initial amount of and change in land cover surrounding each North American BBS route from 2001 to 2016. We quantified species' commonness as a continuous metric at the national scale using the logarithm (base 10) of each species' total count across all routes in the conterminous United States in 2001. For our focal 15-year period, we found that higher proportions of initial natural land cover favored (i.e., were correlated with higher) counts of rare but not common species. We also found that commonness mediated how change in human land cover, but not natural land cover, was associated with species' counts at the end of the study period. Increases in developed lands did not favor counts of any species. Increases in agriculture and declines in pasture favored counts of common but not rare species. Our findings show a signal of commonness in how species respond to a major dimension of global change. Evaluating how and why commonness mediates species' responses to land cover change can help managers design conservation portfolios that sustain the spectrum of common to rare species.

Global Change Biology↗

USGS2014

Survival estimates of wild and captive-bred released Puaiohi, an endangered Hawaiian thrush

Estimating and monitoring adult and juvenile survival are vital to understanding population status, informing recovery planning for endangered species, and quantifying the success of management. We used mark–recapture models to estimate apparent annual survival of the Puaiohi ( Myadestes palmeri ), an endangered thrush endemic to the Hawaiian island of Kauai, from 2005 to 2011. Our sample included 87 wild birds and 123 captive-bred birds that were released at various ages. Survival was higher for wild adult males (0.71 ± 0.09) than for wild adult females (0.46 ± 0.12). Survival of wild juveniles (0.23 ± 0.06) was lower than that of wild adults of both sexes, indicating that recruitment may limit population growth. Captive-bred birds released when <1 yr old had survival (0.26 ± 0.21) comparable with that of wild juveniles, but captive-bred birds released at 1–3 yr old had very low survival (0.05 ± 0.06). Only 8 of 123 (7%) captive birds were seen again after release. Two wild birds resighted five years after marking are the oldest known individuals, being at least six years of age. Malarial infection did not affect survival of wild Puaiohi, unlike many Hawaiian forest birds. The difference between adult male and adult female survival is consistent with rat ( Rattus spp.) predation of females on the nest as a major source of mortality. As such, attempting to reduce nest predation by controlling rats may be the best available management option. Releasing captive-bred birds has had little effect on the wild population in recent years.

The Condor↗

USGS2000

Population status of the Tinian Monarch ( Monarcha takatsukasae ) on Tinian, Commonwealth of the Northern Mariana Islands

We conducted surveys to evaluate the current population status of the Tinian Monarch ( Monarcha takatsukasae ), an insectivorous forest bird restricted to the island of Tinian, Commonwealth of the Northern Mariana Islands. In 1996, we recounted transects surveyed in 1982 and used the same analysis procedure to compare 1982 and 1996 population estimates. The 1996 population estimate was 55,721 ± 3,846 SE (48,345–63,495 95% CI), which is 57% higher than our estimate of 35,846 ± 2,211 SE (31,668–40,337 95% CI) for 1982. Vegetation density, measured by canopy cover and lateral visibility at each station, has also increased since 1982. Our data suggest that the Tinian Monarch population has increased possibly due to increased habitat availability, but remains at risk both from an accidental introduction of brown tree snakes ( Boiga irregularis ) to the island and stochastic processes.

Tinian↗