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At least 1,657 records · Page 92Linked to original sources

USGS2017

Sage grouse

Sage grouse are a group of chicken-sized birds with a unique breeding behavior and dependence on sagebrush shrubs (genus Artemisia) for food and shelter throughout their life cycle. In the last century, human population expansion throughout western North America has reduced the amount of sagebrush and degraded and fragmented the remaining areas. Vanishing sagebrush has resulted in sage grouse (genus Centrocercus) population declines and elevated conservation concern. Western Colorado is home to both species of sage grouse: greater sage grouse (Centrocercus urophasianus) and Gunnison sage grouse (Centrocercus minimus). Populations in the state, and throughout their range, have declined sufficiently to warrant consideration for federal protection for both species under the Endangered Species Act.

Book chapter↗

USGS2014

A hierarchical model combining distance sampling and time removal to estimate detection probability during avian point counts

Imperfect detection during animal surveys biases estimates of abundance and can lead to improper conclusions regarding distribution and population trends. Farnsworth et al. (2005) developed a combined distance-sampling and time-removal model for point-transect surveys that addresses both availability (the probability that an animal is available for detection; e.g., that a bird sings) and perceptibility (the probability that an observer detects an animal, given that it is available for detection). We developed a hierarchical extension of the combined model that provides an integrated analysis framework for a collection of survey points at which both distance from the observer and time of initial detection are recorded. Implemented in a Bayesian framework, this extension facilitates evaluating covariates on abundance and detection probability, incorporating excess zero counts (i.e. zero-inflation), accounting for spatial autocorrelation, and estimating population density. Species-specific characteristics, such as behavioral displays and territorial dispersion, may lead to different patterns of availability and perceptibility, which may, in turn, influence the performance of such hierarchical models. Therefore, we first test our proposed model using simulated data under different scenarios of availability and perceptibility. We then illustrate its performance with empirical point-transect data for a songbird that consistently produces loud, frequent, primarily auditory signals, the Golden-crowned Sparrow ( Zonotrichia atricapilla ); and for 2 ptarmigan species ( Lagopus spp.) that produce more intermittent, subtle, and primarily visual cues. Data were collected by multiple observers along point transects across a broad landscape in southwest Alaska, so we evaluated point-level covariates on perceptibility (observer and habitat), availability (date within season and time of day), and abundance (habitat, elevation, and slope), and included a nested point-within-transect and park-level effect. Our results suggest that this model can provide insight into the detection process during avian surveys and reduce bias in estimates of relative abundance but is best applied to surveys of species with greater availability (e.g., breeding songbirds).

The Auk↗

USGS1991

Wigeongrass ( Ruppia maritima ): a literature review

Wigeongrass (Ruppia maritima L.) is a submersed macrophyte of nearly cosmopolitan distribution and worldwide importance as a waterfowl food. Unfortunately, the plant no longer inhabits vast areas disturbed by human activities. Taxonomic status of the plant is uncertain, especially in North America. In mild climates, in habitats subject to environmental extremes, the plant behaves as an annual (vegetation perishes), or as a perennial in deeper, more stable habitats (some vegetative parts grow year round). Drupelets (seeds) provide a mechanism for wigeongrass to survive periods of drought and excessive water salinity. These sexual propagules can be washed ashore or carried by birds or fish for long distances.Wigeongrass mostly occurs in temporarily to permanently flooded mesohaline-hyperhaline estuarine wetlands, but it also occurs inland in fresh to hypersaline palustrine and lacustrine wetlands. Most populations inhabit warm, relatively unpolluted, and well lit waters <2.0 m deep where fetches and wave action are not great. The species is probably best adapted to stable water levels but can tolerate significant water level fluctuations, including periodic exposure in tidal areas. Robust growth occurs in areas of slow current. Wigeongrass is alone among the submersed North American angiosperms in tolerance to high salinity, but it is likely at a competitive disadvantage among specialist taxa in soft or acidic waters. The species grows in nearly all common bottom substrates, but growth is favored by aerobic and low H 2 S conditions. Turbidity frequently limits wigeongrass growth in waters overlying easily suspendible bottom substrates.Wigeongrass often occurs in monotypic stands, yet grows with many other submersed and emergent macrophytes. Dominance in certain wetlands sometimes alternates with dominance by other submersed macrophytes as salinities, seasonal temperature cycles, or other environmental factors change. The shading effect of metaphytic, planktonic, or epiphytic algae often reduces production.Wigeongrass and its detritus provide food and cover for a large invertebrate biota, although direct consumption of the living plants is minimal. Wigeongrass beds in coastal wetlands are heavily used by fish. The plant is recognized worldwide as an important food of migrant and wintering waterfowl, wading birds, and shorebirds. In subtropical climates, wintering waterfowl can quickly consume entire stands.Propagation and management of wigeongrass has occurred for nearly 60 years in the southern and eastern United States. During the seventies and eighties, sophisticated water level and salinity management techniques have been developed to encourage growth of the plant.Future research should concentrate on determining the means to reduce light-limiting turbidity in many wetland types; understanding the ways in which human activities on and near wetlands affect wigeongrass production; and developing reliable and predictable techniques to stimulate wigeongrass production by water level manipulations and other means in different environmental settings. Trophic interactions and the effects of biomanipulation of fish populations in managed wigeongrass habitat--now little understood--also require more study.

Fish and Wildlife Research↗

USGS2020

Heterogeneity in migration strategies of the whooping crane

Migratory birds use numerous strategies to successfully complete twice-annual movements between breeding and wintering sites. Context for conservation and management can be provided by characterizing these strategies. Variations in strategy among and within individuals support population persistence in response to changes in land use and climate. We used location data from 58 marked Whooping Cranes (Grus americana) from 2010–2016 to characterize migration strategies in the U.S. Great Plains and Canadian Prairies and southern boreal region, and to explore sources of heterogeneity in their migration strategy, including space use, timing, and performance. Whooping Cranes completed approximately 3,900-km migrations that averaged 29 days during spring and 45 days during autumn, while making 11–12 nighttime stops. At the scale of our analysis, individual Whooping Cranes showed little consistency in stopover sites used among migration seasons (i.e., low site fidelity). In contrast, individuals expressed a measure of consistency in timing, especially migration initiation date. Whooping Cranes migrated at different times based on age and reproductive status, where adults with young initiated autumn migration after other birds, and adults with and without young initiated spring migration before subadult birds. Time spent at stopover sites was associated with migration bout length and time spent at previous stopover sites, suggesting Whooping Cranes acquired energy resources at some stopover sites that they used to fuel migration. Whooping Cranes were faithful to a defined migration corridor but showed less fidelity in their selection of nighttime stopover sites; hence, spatial targeting of conservation actions may be better informed by associations with landscape and habitat features rather than documented past use at specific locations. The preservation of variation in migration strategies existing within this species that experienced a severe population bottleneck suggests that Whooping Cranes have maintained a capacity to adjust strategies when confronted with future changes in land use and climate.

Great Plains, Canadian Prairies↗

USGS2010

Baseline survey for rare plant species and native plant communities within the Kamehameha Schools 'Lupea Safe Harbor Planning Project Area, North Kona District, Island of Hawai'i

Kamehameha Schools, in conjunction with several federal, state, and private organizations, has proposed to conduct conservation management on approximately 5,340 ha (~13,200 acres) of land they own in the vicinity of Kīpukalupea in the North Kona District on the island of Hawai'i. The goal of this program is to restore and enhance the habitat to benefit native plant and animal populations that are currently, or were formerly, found in this site. The initial phase of this project has been focused on various activities including conducting baseline surveys for bird and plant species so Kamehameha Schools could develop a Safe Harbor Agreement (SHA) for the proposed project lands relative to the habitat management and species reintroduction efforts they would like to conduct in the Lupea Project area. This report summarizes methods that were used to collect field data on plant species and communities within the project area, and the results of that initial survey. The information was used to calculate baseline values for all listed threatened or endangered plant species found, or expected to be found, within the project area, and to design a monitoring program to assess changes in plant communities and rare plant species relative to management activities over the duration of the SHA. The Lupea Project area contains excellent examples of several high elevation native plant communities including montane dry forest and woodland, native subalpine shrubland, and native grassland. Between November 2003 and January 2004 we sampled plant communities and species along seven transects established through the project area. A total of 109 plant species were found during this survey, within the transect grid and in nearby areas. Forty-four of these plants are endemic species, 21 are indigenous species, 43 are introduced, and one species is believed to have been introduced to Hawai&bdquo;i by early Polynesian settlers. Only one federally listed Endangered plant, Asplenium peruvianum var. insulare , was found within the survey area. Additionally, we found one immature plant that may be Sicyos macrophyllus , a candidate species for listing. However, we were not able to make a definite determination of this species‟ identity since it did not have fruits or flowers. Finally, we documented four plant species within the survey area that have no official status designation but are considered to be rare and informally recognized as “species of concern” (SOC) as they appear to be declining in distribution and abundance statewide. These included Chamaesyce olowaluana, Eragrostis deflexa, Sisyrinchium acre, and Tetramolopium consanguineum . In addition to conducting field surveys, we performed a query on a spatial database developed by Dr. Jonathan Price of the University of Hawai&bdquo;i at Hilo which models the potential range of all native Hawaiian plant species based on historic observations and a set of environmental parameters. The potential species list for the Lupea Project area includes 47 taxa that we did not find during our surveys, as well as three other listed species that were not modeled by Price, but known from historic records in adjacent habitats. Some of these species are extremely rare or, in some cases have been locally extirpated. However, most of the plants that were predicted but not found during our surveys are expected to be located with additional searching, or may potentially recolonize the area following the elimination of ungulates and initiation of other restoration efforts. Forty-four introduced plant species were found within the survey area, seven of which are considered to be highly invasive. These include the grasses Pennisetum clandestinum and Pennisetum setaceum , vines Delairea odorata and Passiflora tarminiana , herbs Senecio madagascariensis and Verbascum thapsus , and the shrub Rubus niveus . Non-zero baseline values are proposed for the one listed plant species found within the Lupea Project area, one species that is a candidate for listing, and the four other rare species we found that may be considered for listing in the future. Additionally, a zero baseline is proposed for 23 other species that were predicted, but not found within the project area. These include 14 Endangered species, one Threatened species, two candidates for listing, and six species of concern. Subsequent monitoring of the site will be necessary to determine if the populations of these species have increased or decreased relative to their baseline values. It is presumed that the management activities Kamehameha Schools has proposed for this area, particularly removal of the ungulates and weed control, will provide a benefit to the habitat as a whole and allow for natural regeneration and maintenance of the all elements of the plant communities found there.

Hawaii↗

USGS2016

Colonial waterbird predation on Lost River and Shortnose suckers in the Upper Klamath Basin

We evaluated predation on Lost River Suckers Deltistes luxatus and Shortnose Suckers Chasmistes brevirostris by American white pelicans Pelecanus erythrorhynchos and double-crested cormorants Phalacrocorax auritus nesting at mixed-species colonies in the Upper Klamath Basin of Oregon and California during 2009–2014. Predation was evaluated by recovering (detecting) PIT tags from tagged fish on bird colonies and calculating minimum predation rates, as the percentage of available suckers consumed, adjusted for PIT tag detection probabilities but not deposition probabilities (i.e., probability an egested tag was deposited on- or off-colony). Results indicate that impacts of avian predation varied by sucker species, age-class (adult, juvenile), bird colony location, and year, demonstrating dynamic predator–prey interactions. Tagged suckers ranging in size from 72 to 730 mm were susceptible to cormorant or pelican predation; all but the largest Lost River Suckers were susceptible to bird predation. Minimum predation rate estimates ranged annually from <0.1% to 4.6% of the available PIT-tagged Lost River Suckers and from <0.1% to 4.2% of the available Shortnose Suckers, and predation rates were consistently higher on suckers in Clear Lake Reservoir, California, than on suckers in Upper Klamath Lake, Oregon. There was evidence that bird predation on juvenile suckers (species unknown) in Upper Klamath Lake was higher than on adult suckers in Upper Klamath Lake, where minimum predation rates ranged annually from 5.7% to 8.4% of available juveniles. Results suggest that avian predation is a factor limiting the recovery of populations of Lost River and Shortnose suckers, particularly juvenile suckers in Upper Klamath Lake and adult suckers in Clear Lake Reservoir. Additional research is needed to measure predator-specific PIT tag deposition probabilities (which, based on other published studies, could increase predation rates presented herein by a factor of roughly 2.0) and to better understand biotic and abiotic factors that regulate sucker susceptibility to bird predation.

California, Oregon↗

USGS2018

Public acceptability of development in the Northern Forest of Vermont, USA – the influence of wildlife information, recreation involvement, and demographic characteristics

Increasing development such as roads and houses will alter future landscapes and result in biological, social, and economic trade-offs. Managing development requires information on the public’s acceptability of development and understanding which factors shape acceptability. In this study, we examined three questions: 1) What is the public’s acceptability of development? 2) Is acceptability of development influenced by wildlife information? and 3) Is the maximum amount of acceptable development influenced by views about wildlife, involvement in outdoor recreation, and demographic factors? We conducted a visual-preference survey of 9,000 households in Vermont, USA that asked about acceptable levels of development, acceptability of wildlife, involvement in recreation, and individual and town demographics. The survey response rate was 44%. Maximum acceptable condition (MAC) for development was 41 houses/km 2 and not meaningfully influenced by broader consequences of development on seven common wildlife species. MAC was influenced by views on individual species, including bear and coyote, but not by other species such as deer, fox, and bobcat. Respondents with a positive attitude toward bear favored less development, whereas the opposite relationship existed for coyote. Similarly, MAC was negatively influenced by involvement in birding and hunting, but not by other common recreational activities. Among demographic factors, respondents that were younger and not born in Vermont were more accepting of development. Population density also positively influenced development acceptability. Results provide measures of the public’s acceptability of development that can help guide decision-making about development, wildlife, and recreation management.

Vermont↗

USGS2015

Estimating wind-turbine-caused bird and bat fatality when zero carcasses are observed

Many wind-power facilities in the United States have established effective monitoring programs to determine turbine-caused fatality rates of birds and bats, but estimating the number of fatalities of rare species poses special difficulties. The loss of even small numbers of individuals may adversely affect fragile populations, but typically, few (if any) carcasses are observed during monitoring. If monitoring design results in only a small proportion of carcasses detected, then finding zero carcasses may give little assurance that the number of actual fatalities is small. Fatality monitoring at wind-power facilities commonly involves conducting experiments to estimate the probability ( g ) an individual will be observed, accounting for the possibilities that it falls in an unsearched area, is scavenged prior to detection, or remains undetected even when present. When g < 1, the total carcass count ( X ) underestimates the total number of fatalities ( M ). Total counts can be 0 when M is small or when M is large and g ≪1. Distinguishing these two cases is critical when estimating fatality of a rare species. Observing no individuals during searches may erroneously be interpreted as evidence of absence. We present an approach that uses Bayes' theorem to construct a posterior distribution for M , i.e., P ( M | X , ĝ ), reflecting the observed carcass count and previously estimated g . From this distribution, we calculate two values important to conservation: the probability that M is below a predetermined limit and the upper bound ( M * ) of the 100(1 − α)% credible interval for M . We investigate the dependence of M * on α, g , and the prior distribution of M , asking what value of g is required to attain a desired M * for a given α. We found that when g < ~0.15, M * was clearly influenced by the mean and variance of ĝ and the choice of prior distribution for M , but the influence of these factors is minimal when g > ~0.45. Further, we develop extensions for temporal replication that can inform prior distributions of M and methods for combining information across several areas or time periods. We apply the method to data collected at a wind-power facility where scheduled searches yielded X = 0 raptor carcasses

Ecological Applications↗

USGS2013

Golden eagle records from the Midwinter Bald Eagle Survey: information for wind energy management and planning

The purpose of this Data Series report is to provide the occasions, locations, and counts when golden eagles were recorded during the annual Midwinter Bald Eagle Surveys. Golden eagles (Aquila chrysaetos) are protected by Federal statutes including the Bald and Golden Eagle Protection Act (BGEPA) (16 USC 668-668c) and the Migratory Bird Treaty Act (MBTA) (16 USC 703-12). The U.S. Fish and Wildlife Service (Service) manages golden eagles with the goal of maintaining stable or increasing breeding populations (U.S. Fish and Wildlife Service, 2009). Development for the generation of electricity from wind turbines is occurring in much of the range of the golden eagle in the western United States. Development could threaten population stability because golden eagles might be disturbed by construction and operation of facilities and they are vulnerable to mortality from collisions with wind turbines (Smallwood and Thelander, 2008). Therefore, the Service has proposed a process by which wind energy developers can collect information that could lead to Eagle Conservation Plans (ECP), mitigation, and permitting that allow for golden eagle management in areas of wind energy development (U.S. Fish and Wildlife Service, 2011). The Service recommends that ECP be developed in stages, and the first stage is to learn if golden eagles occur at the landscape level where potential wind facilities might be located. Information about where eagles occur can be obtained from technical literature, agency files, and other sources of information including on-line biological databases. The broad North American distribution of golden eagles is known, but there is a paucity of readily available information about intermediate geographic scales and site-specific scales, especially during the winter season (Kochert and others, 2002).

Data Series↗

USGS2006

Trends in Streamflow of the San Pedro River, Southeastern Arizona

Total annual streamflow of the San Pedro River at Charleston in southeastern Arizona (fig. 1) decreased by about 66 percent from 1913 to 2002 (fig. 2). The San Pedro River is one of the few remaining free-flowing perennial streams in the arid Southwestern United States, and the riparian forest along the river supports several endangered species and is an important habitat for migratory birds. The decreasing trend in streamflow has led to concerns that riparian habitat may be damaged and that overall long-term water supply for a growing population may be threatened. Resource managers and the public have an interest in learning more about the trend and the possible causes of the trend.

Fact Sheet↗

USGS2004

Effects of flow modification on a cattail wetland at the mouth of Irondequoit Creek near Rochester, New York: Water levels, wetland biota, sediment, and water quality

An 11-year (1990-2001) study of the Ellison Park wetland, a 423-acre, predominantly cattail (Typha glauca) wetland at the mouth of Irondequoit Creek, was conducted to document the effects that flow modifications, including installation of a flow-control structure (FCS) in 1997 and increased diversion of stormflows to the backwater areas of the wetland, would have on the wetland's ability to decrease chemical loads transported by Irondequoit Creek into Irondequoit Bay on Lake Ontario. The FCS was designed to raise the water-surface elevation and thereby increase the dispersal and detention of stormflows in the upstream half of the wetland; this was expected to promote sedimentation and microbial utilization of nutrients, and thereby decrease the loads of certain constituents, primarily phosphorus, that would otherwise be carried into Irondequoit Bay. An ecological monitoring program was established to document changes in the wetland's water levels, biota, sedimentation rates, and chemical quality of water and sediment that might be attributable to the flow modifications. Water-level increases during storms were mostly confined to the wetland area, within about 5,000 ft upstream from the FCS. Backwater at a point of local concern, about 13,000 ft upstream, was due to local debris jams or constriction of flow by bridges and was not attributable to the FCS. Plant surveys documented species richness, concentrations of nutrients and metals in cattail tissues, and cattail productivity. Results indicated that observed differences among survey periods and between the areas upstream and downstream from the FCS were due to seasonal changes in water levels—either during the current year or at the end of the previous year's growing season—that reflected the water-surface elevation of Lake Ontario, rather than water-level control by the FCS. Results showed no adverse effects from the naturally high water levels that prevail annually during the spring and summer in the wetland, nor from the short-duration increases in water levels that result from FCS operation. Fish surveys documented the use of the wetland by 44 species, of which 25 to 29 species were found in any given year. Community composition was relatively consistent during the study, but seasonal and year-to-year variations in dominant resident and nonresident species were noted, and probably reflected natural or regional population patterns in Lake Ontario and Irondequoit Bay. The FCS allowed fish passage at all water levels and had no discernible adverse effect on the fish community. Bird surveys documented the use of the wetland by more than 90 species for breeding, feeding, and migration. Ground-nesting birds were unaffected by the FCS. Seasonally high water levels, rather than short-duration increases caused by the FCS, might have caused the scarcity or absence of certain wetland species by limiting the extent of breeding habitat for some species and the exposure of mud flats that attracted other species. Some noticeably scarce or absent species also were rare or absent elsewhere along the south-central shore of Lake Ontario. Benthic-macroinvertebrate studies were of minimal use for evaluating the effect of the FCS because no surveys were conducted after FCS installation. The precontrol results allowed assessment of the ecological quality of the wetland on the basis of biotic indices, and generally indicated moderately to severely impaired conditions. Differences between the macroinvertebrate communities in the southern part of the wetland and those in the northern part were attributed to habitat differences, such as substrate composition, water depth, and density of submerged aquatic vegetation. Sedimentation rates in the areas upstream and downstream from the FCS increased after the flow modifications, more in the area upstream from the FCS than in the downstream area. The concurrent downstream increase and the dynamic patterns of deposition and scour indicated that although the FCS and the other flow modifications undoubtedly were major factors in the postcontrol upstream increase in sedimentation rates, other factors, such as the magnitude, frequency, and the timing (season) of peak flows, might also have contributed. Periodic analyses of sediment samples from three longterm depositional sites in the wetland documented the concentrations of major and trace elements, polycyclic aromatic hydrocarbons, and organochlorine and organophosphate compounds. The concentrations of most constituents showed no substantial fluctuation or consistent upward or downward trend during the years sampled, nor did they identify any change after FCS installation. Comparison of the measured concentrations with sediment-quality guidelines that are used to assess the ecological quality of substrate environments indicated that the wetland was moderately to severely impaired—an assessment consistent with the benthic-macroinvertebrate biotic indices. During the precontrol period (1990–96), the wetland was a sink for particulate constituents (removal efficiencies for total phosphorus and total suspended solids were 28 and 47 percent, respectively), but had little effect on conservative constituents (chloride and sulfate). The wetland was a source of orthophosphate and ammonia (removal efficiencies were -38 and -84 percent, respectively). During the postcontrol period (1997–2001), the wetland continued to be a sink for particulate constituents (removal efficiencies for total phosphorus and total suspended solids were 45 and 52 percent, respectively); the exportation of orthophosphate by the wetland decreased (by 7 percent), whereas that of ammonia increased (by about 70 percent). The outflow loads of orthophosphate and ammonia represented about 15 and 2.3 percent of total phosphorus and total nitrogen loads, respectively. Changes in the loads of conservative constituents were negligible, and the overall removal efficiencies for other constituents during the precontrol period differed from those of the postcontrol period by no more than 5.4 percent. Statistical analyses of monthly inflow and outflow loads indicated significant differences between inflow and outflow loads of most constituents during the pre- and postcontrol periods. Load data were adjusted to remove the effects of dissimilar hydrologic conditions that prevailed during the pre- and postcontrol periods, and to isolate the water-quality-improvement effect that could be attributed solely to the FCS. Results indicated that the FCS contributed significantly to the decrease in total phosphorus loads, and slightly to a decrease in ammonia-plus-organic nitrogen loads, but had little or no significant effect on loads of other constituents.

New York↗

USGS2009

Hemlock ecosystem monitoring of New River Gorge National River and Gauley River National Recreation Area vegetation and bird communities: 1998–2008

We initiated a long-term hemlock ecosystem monitoring study in 1998 on the New River Gorge National River (NERI) and Gauley River National Recreation Area (GARI), in Nicholas, Fayette, and Raleigh counties, West Virginia, to quantify the effects of hemlock woolly adelgid (HWA) on forest ecosystem dynamics. Hemlock vigor and degree of adelgid infestation were sampled in each fall 1998 through 2007 except 1999 and 2005; vegetation structure and composition were sampled in summer 1999 and 2007; and avian populations were sampled each summer 1999 through 2008. HWA was first detected on sampling plots in 2004 when it was found on eight of 36 plots and reached a high of 22 plots in 2006. Although hemlock crown vigor has declined, limited hemlock mortality has occurred. Consequently, vegetation structure and bird communities have changed little. However, because the literature suggests that tree mortality can occur within four to six years of infestation, we expect hemlock mortality to ensue.

West Virginia↗

USGS2004

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

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

The Auk↗

USGS2008

Seasonal survival of radiomarked emperor geese in western Alaska

The population of emperor geese ( Chen canagica ) in western Alaska, USA, declined by >50% from the 1960s to the mid‐1980s and has increased only slightly since. Rates of population increase among arctic geese are especially sensitive to changes in adult survival. Improving adult survival in seasons or geographic areas where survival is low may be the best means of increasing the emperor goose population. We monitored fates of 133 adult female emperor geese that were radiomarked with surgically implanted very high frequency or satellite radiotransmitters from 1999 to 2004 to assess whether monthly survival varied among years, seasons, or geographic areas. Because of uncertainties in determining whether a bird had died based on the radio signal, we analyzed 2 versions of the data. One version used conservative criteria to identify which birds had died based on radio signals and the other used more liberal criteria. In the conservative version of the data we detected 12 mortalities of emperor geese, whereas in the liberal interpretation there were 18 mortalities. In both versions, the models with greatest support indicated that monthly survival varied seasonally and that compared to most seasons estimated monthly survival was lower (φ = 0.95–0.98) in May and August when emperor geese were mainly on the Yukon‐Kuskokwim Delta. From 44% to 47% of annual mortality occurred in those months. Estimated monthly survival was higher (φ = 0.98–1.0) from September through March when emperor geese were at autumn staging or wintering areas and in June and July when birds were nesting, rearing broods, or molting. Estimated annual survival was 0.85 (95% CI = 0.77–0.92) in the best‐supported model when we used conservative criteria to identify mortalities and 0.79 (95% CI = 0.74–0.85) under the best model using liberal mortality criteria. Lower survival in August and May corresponded to periods when subsistence harvest of emperor geese was likely highest. Managers may be able to most effectively influence population growth rate of emperor geese by reducing subsistence harvest on the Yukon‐Kuskokwim Delta in May and August.

Alaska↗

USGS2015

Optimal population prediction of sandhill crane recruitment based on climate-mediated habitat limitations

Prediction is fundamental to scientific enquiry and application; however, ecologists tend to favour explanatory modelling. We discuss a predictive modelling framework to evaluate ecological hypotheses and to explore novel/unobserved environmental scenarios to assist conservation and management decision-makers. We apply this framework to develop an optimal predictive model for juvenile (<1 year old) sandhill crane Grus canadensis recruitment of the Rocky Mountain Population (RMP). We consider spatial climate predictors motivated by hypotheses of how drought across multiple time-scales and spring/summer weather affects recruitment. Our predictive modelling framework focuses on developing a single model that includes all relevant predictor variables, regardless of collinearity. This model is then optimized for prediction by controlling model complexity using a data-driven approach that marginalizes or removes irrelevant predictors from the model. Specifically, we highlight two approaches of statistical regularization, Bayesian least absolute shrinkage and selection operator (LASSO) and ridge regression. Our optimal predictive Bayesian LASSO and ridge regression models were similar and on average 37% superior in predictive accuracy to an explanatory modelling approach. Our predictive models confirmed a priori hypotheses that drought and cold summers negatively affect juvenile recruitment in the RMP. The effects of long-term drought can be alleviated by short-term wet spring–summer months; however, the alleviation of long-term drought has a much greater positive effect on juvenile recruitment. The number of freezing days and snowpack during the summer months can also negatively affect recruitment, while spring snowpack has a positive effect. Breeding habitat, mediated through climate, is a limiting factor on population growth of sandhill cranes in the RMP, which could become more limiting with a changing climate (i.e. increased drought). These effects are likely not unique to cranes. The alteration of hydrological patterns and water levels by drought may impact many migratory, wetland nesting birds in the Rocky Mountains and beyond. Generalizable predictive models (trained by out-of-sample fit and based on ecological hypotheses) are needed by conservation and management decision-makers. Statistical regularization improves predictions and provides a general framework for fitting models with a large number of predictors, even those with collinearity, to simultaneously identify an optimal predictive model while conducting rigorous Bayesian model selection. Our framework is important for understanding population dynamics under a changing climate and has direct applications for making harvest and habitat management decisions.

Journal of Animal Ecology↗

USGS2014

Distribution and prevalence of knemidokoptic mange in Hawai`i `Amakihi on the island of Hawaii

Knemidokoptic mange was first observed on two Hawai‘i ‘Amakihi (Hemignathus virens) mist netted in Manuka Natural Area Reserve (NAR) on the Island of Hawai‘i in June 2007. Microscopic examination of skin scrapings from lesions of the infested individuals revealed the scaley-leg mite, Knemidokoptes jamaicensis. Continued surveillance at Manuka NAR (2007-2009) documented a 24% (15/63) prevalence of mange among Hawai‘i ‘Amakihi distributed from coastal habitat to 1,500 m above sea level (asl). From 2012-2014, we conducted an island-wide survey of wild passerine birds from several leeward sites (Manuka NAR, Kahuku Unit of Hawai‘i Volcanoes National Park (HAVO), Pu‘u Wa‘awa‘a Forest Bird Sanctuary, and Kipahoehoe NAR) and windward sites (Hakalau Forest National Wildlife Refuge, ‘Ᾱinahou Ranch of HAVO, Malama Ki Forest Reserve, and Keauohana Forest Reserve) to determine the current distribution and host range of knemidokoptic mange. We also determined the prevalence of malaria in Hawai‘i ‘Amakihi populations where mange was present and treated a subset of infested Hawai‘i ‘Amakihi mange with a single, topical dose of moxidectin. We mist netted and examined a total of 1,734 passerines, including 738 Hawai‘i ‘Amakihi. Mange was present in Hawai‘i ‘Amakihi at Manuka NAR (595 and 305 m asl), Kahuku Ranch Unit of HAVO (Glover site: 1,201 m asl and Kipuka Akala site: 1,532 m asl), Malama Ki Forest Reserve and Keauohana Forest Reserve (293 m asl). No other passerine birds (n = 995) were infected. Mange prevalence ranged from a high of 69% (40/58) in Keauohana Forest Reserve to a low of 2% (1/65) in the Kahuku Ranch Unit of HAVO (Kipuka Akala). At Manuka NAR prevalence had decreased from 26% in 2010 to 10% (7/81) in 2012–2014. We found no significant relationship between the prevalence of mange and the prevalence of avian malaria in mesic habitats at Manuka NAR (P = 0.59 (FET, n = 81)), but there was a significant association between the prevalence of mange and the prevalence of malaria in lowland wet forests in Puna Forest Reserves (P < 0.01 (FET, n = 72)). This apparent association may be a reflection of the high prevalence of malaria (>80%) in these areas. There was no difference in the frequency of recapture of birds that were infested versus un-infested at first capture at our long-term sites (Manuka NAR and Puna sites) (χ2(1, n = 227) = 1.51, P = 0.22, but when all sites with mange present were pooled, there was a significant difference in the frequency of recaptures between infested and un-infested birds (χ2(1, n = 424) = 7.13, P = 0.01). There was a significant association between parasitemia level (per 10,000 RBCs) and the ranked stage of mange present in infested individuals. We treated 24 Hawai‘i ‘Amakihi with moxidectin and upon recapture (n = 2), found a reduction in both the size and stage of mange lesions, such that a single dose, topical treatment of moxidectin appears to be an effective treatment for knemidokoptic mange in wild populations. Our results suggest that knemidokoptic mange is currently limited to Hawai‘i ‘Amakihi and prevalent in low elevation sites on both the windward and leeward sides of the island.

Hawaii↗

USGS2002

Influence of hydrology on life-history parameters of common freshwater fishes from southern Florida

Fishes are essential to the successful functioning of wetland food webs in southern Florida through their roles as prey and predators. Any changes that reduce the population sizes, community composition, or availability of aquatic animals will affect all facets of the ecology of these wetlands. In particular, small and medium-size fishes are important food items for most wading bird species. For this reason, fishes have been recognized by the multi-agency groups responsible for guiding the Everglades restoration process as a key indicator group by which to measure restoration success. Despite the importance of fish for management, gaps in baseline knowledge remain. Basic demographic information, termed life-history parameters, is needed to make predictions about their resilience under alternative management scenarios. These parameters include growth rate, age at maturation, fecundity and life expectancy. However, basic life-history parameters remain to be characterized, even for abundant fish species. Adding to the challenge, life-history characteristics of important Everglades species are known to be plastic in response to environmental conditions and survivorship and recruitment schedules are certain to be influenced by variation in hydroperiod. We intend to study the effect of hydroperiod on recruitment, size/age structure, growth, and fecundity, which, in turn, determine fish population dynamics. At present, data on fish reproduction, age and growth, and other life history characteristics are confined to a few species from a limited area of long-hydroperiod marsh in central Shark River Slough. As we continue the analysis and synthesis of data from the long-term fish collections, life-history information will help explain patterns of fluctuations in the time series. Accurate life-history data are also very important in building credible simulation models like ATLSS. Without empirical life-history data from a range of environments, the model will be simplistic and inadequate.

Florida↗

USGS2010

A sampling plan for riparian birds of the Lower Colorado River-Final Report

A sampling plan was designed for the Bureau of Reclamation for selected riparian birds occurring along the Colorado River from Lake Mead to the southerly International Boundary with Mexico. The goals of the sampling plan were to estimate long-term trends in abundance and investigate habitat relationships especially in new habitat being created by the Bureau of Reclamation. The initial objective was to design a plan for the Gila Woodpecker (Melanerpes uropygialis), Arizona Bell's Vireo (Vireo bellii arizonae), Sonoran Yellow Warbler (Dendroica petechia sonorana), Summer Tanager (Piranga rubra), Gilded Flicker (Colaptes chrysoides), and Vermilion Flycatcher (Pyrocephalus rubinus); however, too little data were obtained for the last two species. Recommendations were therefore based on results for the first four species. The study area was partitioned into plots of 7 to 23 hectares. Plot borders were drawn to place the best habitat for the focal species in the smallest number of plots so that survey efforts could be concentrated on these habitats. Double sampling was used in the survey. In this design, a large sample of plots is surveyed a single time, yielding estimates of unknown accuracy, and a subsample is surveyed intensively to obtain accurate estimates. The subsample is used to estimate detection ratios, which are then applied to the results from the extensive survey to obtain unbiased estimates of density and population size. These estimates are then used to estimate long-term trends in abundance. Four sampling plans for selecting plots were evaluated based on a simulation using data from the Breeding Bird Survey. The design with the highest power involved selecting new plots every year. Power with 80 plots surveyed per year was more than 80 percent for three of the four species. Results from the surveys were used to provide recommendations to the Bureau of Reclamation for their surveys of new habitat being created in the study area.

Open-File Report↗