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USGS2022

How effective is the Birdsbesafe® cat collar at reducing bird mortality by domestic cats?

The global decline of songbird populations is a well-recognized conservation issue. Domestic cats kill an estimated 2.4 billion birds each year in the United States alone—more than most other anthropogenic threats combined. As many pet owners are reluctant to keep their cats inside, collar-mounted antipredation devices for domestic cats may be an important conservation tool. We examined the effectiveness of the Birdsbesafe® collar cover (BCC), a sleeve of brightly patterned fabric worn over a typical breakaway collar. The BBC's designers intend for the collar's bright colors to alert potential prey to the cat's presence. By combining data from two studies in New York (2014 and 2019) and one in Florida (2019), all of which used similar methods, we tested the hypothesis that the BCC effectively reduces avian mortality caused by cats of different ages and sexes in different hunting environments. We tested 94 cats over a 12-wk period in New York in 2014 or 8-wk periods in Florida and New York in 2019 during the bird breeding seasons; cats alternated 2-wk periods with and without the collar. Across studies, we recovered 2.7 times fewer birds per cat with the BCC than without ( P = 0.006). The BCC was more effective at a temperate latitude than a subtropical one ( P = 0.047). There was no difference in the effectiveness of the BCC for cats of varying ages, sexes, or hunting environments. Our results suggest that the BCC could be one tool within a larger effort to decrease domestic cat predation of songbirds.

Florida, New York↗

USGS2020

Drones provide a better method to find nests and estimate nest survival for colonial waterbirds: A demonstration with Western Grebes

Drone use in wildlife biology has greatly increased as they become cheaper and easier to deploy in the field. In this paper we describe a less invasive method of using drones and exploring their limitations for studying colonial nesting waterbirds. Western Grebes, like most colonial nesting waterbirds, can be very sensitive to human interaction. Using a 3DR Solo quad copter equipped with a high-resolution digital camera we were able to effectively map and monitor a Western Grebe breeding colony throughout the nesting period with a series of 6 flights. We were able to use drone collected aerial imagery to model nest survival while minimizing disturbance to the birds. However, we were not able to deploy the drone at all of our study sites. Our ability to effectively deploy the drone was hindered by the environmental and vegetation characteristics of a site. Drone technology can be a useful tool, especially when studying a species sensitive to human interaction. However, there researchers should carefully consider their species and study site to evaluate if a drone is the proper tool to meet their objectives.

Idaho↗

USGS2008

Assessment of metals exposure and sub-lethal effects in voles and small birds captured near the DeLong Mountain Regional Transportation System Road, Cape Krusenstern National Monument, Alaska, 2006

Voles (n=6) and small ground-nesting birds (n=12) were live-captured near the DeLong Mountain Regional Transportation System haul road in Cape Krusenstern National Monument in northwest Alaska in 2006 to assess metals exposure and sub-lethal biological effects. Similar numbers of animals were captured from a reference site in southern Cape Krusenstern National Monument for comparison. Histopathological examination of selected organs, blood analysis, and analysis for aluminum, barium, cadmium, lead, and zinc concentrations in liver and blood samples were performed. Voles and small birds captured from near the haul road had about 20 times greater blood and liver lead concentrations and about 3 times greater cadmium concentrations when compared to those from the reference site. Barium and zinc tissue concentrations of animals collected from different sites were not remarkably different, and aluminum concentrations were below the reporting limits in most samples. There was no clear evidence of serious sub-lethal biological effects such as lesions in internal organs or DNA damage in blood in any of the animals. Accordingly, blood and liver lead concentrations in animals captured near the haul road generally were less than tissue concentration thresholds associated with serious biological effects reported from other studies; however, subtle effects resulting from lead exposure, such as the suppression of the activity of certain enzymes, cannot be ruled out for those animals nearest the haul road. Notably, liver lead concentrations of voles and small birds at the reference location were considerably less than those previously reported for similar animals at reference sites in other parts of the United States, Canada, and Europe. Results from this reconnaissance-level study indicate that voles and small birds inhabiting this area are not suffering serious biological effects as a result of metals exposure; however, continued monitoring of lead and other metals is recommended because of uncertainties noted and because biological effects thresholds might be approached if exposure levels were to increase.

Scientific Investigations Report↗

USGS2017

CYP1A protein expression and catalytic activity in double-crested cormorants experimentally exposed to Deepwater Horizon Mississippi Canyon 252 oil

Double-crested cormorants ( Phalacrocorax auritus , DCCO) were orally exposed to Deepwater Horizon Mississippi Canyon 252 (DWH) oil to investigate oil-induced toxicological impacts. Livers were collected for multiple analyses including cytochrome P4501A (CYP1A) enzymatic activity and protein expression. CYP1A enzymatic activity was measured by alkoxyresorufin O-dealkylase (AROD) assays. Activities specific to the O-dealkylation of four resorufin ethers are reported: benzyloxyresorufin O-debenzylase (BROD), ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and pentoxyresorufin O-depentylase (PROD). CYP1A protein expression was measured by western blot analysis with a CYP1A1 mouse monoclonal antibody. In study 1, hepatic BROD, EROD, and PROD activities were significantly induced in DCCO orally exposed to 20 ml/kg body weight (bw) oil as a single dose or daily for 5 days. Western blot analysis revealed hepatic CYP1A protein induction in both treatment groups. In study 2 (5 ml/kg bw oil or 10 ml/kg bw oil, 21 day exposure), all four hepatic ARODs were significantly induced. Western blots showed an increase in hepatic CYP1A expression in both treatment groups with a significant induction in birds exposed to 10 ml/kg oil. Significant correlations were detected among all 4 AROD activities in both studies and between CYP1A protein expression and both MROD and PROD activities in study 2. EROD activity was highest for both treatment groups in both studies while BROD activity had the greatest fold-induction. While PROD activity values were consistently low, the fold-induction was high, usually 2nd highest to BROD activity. The observed induced AROD profiles detected in the present studies suggest both CYP1A4/1A5 DCCO isoforms are being induced after MC252 oil ingestion. A review of the literature on avian CYP1A AROD activity levels and protein expression after exposure to CYP1A inducers highlights the need for species-specific studies to accurately evaluate avian exposure to oil.

Ecotoxicology and Environmental Safety↗

USGS2023

Monitoring Avian Productivity and Survivorship (MAPS) 6-year summary, Naval Outlying Landing Field, Imperial Beach, southwestern San Diego County, California, 2014–20

Executive Summary From 2014 to 2020, a Monitoring Avian Productivity and Survivorship (MAPS) banding station (station) was operated at the Naval Outlying Landing Field (NOLF), Imperial Beach, in southwestern San Diego County, California. The station was established as part of a long-term monitoring program of Neotropical migratory bird populations on NOLF and helps Naval Base Coronado (NOLF is a component) meet the goals and objectives of the Department of Defense Partners in Flight program and the Birds and Migratory Birds Management Strategies of the Naval Base Coronado Integrated Natural Resources Management Plan. The station was established in 2009 and has been in operation during the spring and summer since 2009 except for 2016 when it was not funded. The station was operated by AMEC Earth and Environmental, Inc., from 2009 to 2011, by the U.S. Geological Survey from 2012 to 2015, the San Diego Natural History Museum in 2017, and the U.S. Geological Survey again from 2018 to 2023. This report synthesizes results from 2014 to 2020. A prior report presents summaries and analyses from 2009 to 2013. The banding station at NOLF was operated according to the standard MAPS protocol with some exceptions. Ten mist nets used to capture birds were erected in fixed locations that remained consistent between and within years, with few minor relocations. Nets were open for 6 hours per day, once every 10 days (a netting period) for 13 netting periods starting April 1 each year. Occasionally, poor weather conditions (for example, rain, wind, or excessive heat) prevented net operation or forced nets to be closed early (or, rarely, late). Nets were checked periodically throughout the day and birds were removed, processed (leg bands affixed, measurements recorded), and released. From 2014 to 2020, we had 3,543 captures (including initial captures and recaptures) of a maximum of 3,264 year-unique captures (543±143 year-unique captures [the total number of individual birds captured for the first time each year]). The count of year-unique captures included 2,702 newly banded birds, 258 individuals that were recaptured from previous years, and 304 birds that were released unbanded (218 hummingbirds and 86 other birds that were intentionally released unbanded [game birds, and so forth] or escaped before banding). Individuals of 68 species were captured, 39 of which breed at or in the immediate vicinity of the MAPS banding station. Bird capture rate averaged 43±30 captures per day (corrected to account for variation in effort) for all years (range 7–163 effort-corrected captures per day) and species richness per year averaged 43±4. Bushtit ( Psaltriparus minimus ) was the most abundant species captured, followed by Orange-crowned Warbler ( Leiothlypis celata ), Wilson’s Warbler ( Cardellina pusilla ), House Finch ( Haemorhous mexicanus ), Song Sparrow ( Melospiza melodia ), and Common Yellowthroat ( Geothlypis trichas ). The mean adult sex ratio of all species combined across all years was 54:46 male:female. Adults averaged 73±12 percent of known age captures per year (range 59–94 percent), and juveniles averaged 27±12 percent (range 6–41 percent). Nineteen sensitive species were detected at NOLF (12 captured and 7 observed only). During 2014–20, we captured one State and federally endangered species, Least Bell’s Vireo ( Vireo bellii pusillus ); one federally threatened species, California Gnatcatcher ( Polioptila californica ); one State endangered species, Willow Flycatcher ( Empidonax traillii ); and two State species of concern, Yellow-breasted Chat ( Icteria virens ) and Yellow Warbler ( Setophaga petechia ). One additional State species of concern, Northern Harrier ( Circus hudsonius ), was observed at the MAPS banding station but not captured. Peregrine Falcon ( Falco peregrinus ) and White-tailed Kite ( Elanus leucurus ), California State fully protected species, also were observed at the MAPS banding station. Seven federal bird species of conservation concern—Calliope Hummingbird ( Selasphorus calliope ), Rufous Hummingbird ( Selasphorus rufus ), Allen’s Hummingbird ( Selasphorus sasin ), Nuttall’s Woodpecker ( Dryobates nuttallii ), Wrentit ( Chamaea fasciata ), California Thrasher ( Toxostoma redivivum ), and Lawrence’s Goldfinch ( Spinus lawrencei )—also were captured, and four additional federal bird species of conservation concern—Willet ( Tringa semipalmata ), Western Gull ( Larus occidentalis ), California Gull ( Larus californicus ), and Bullock’s Oriole ( Icterus bullockii )—were observed but not captured. Local population trends varied among species and years. From 2012 to 2019, year-round residents Bushtit, Song Sparrow, and Common Yellowthroat significantly decreased, whereas the migrant Least Bell’s Vireo increased. The total number of captures for all species except Least Bell’s Vireo was lowest in 2017, corresponding to the habitat damage caused by Kuroshio shot hole borer beetle ( Euwallacea kuroshio ) in the Tijuana River Valley. Annual productivity and annual adult survival were calculated for seven breeding species based on criteria used by the Institute for Bird Populations (Least Bell’s Vireo, Bushtit, Wrentit, House Wren [ Troglodytes aedon ], Song Sparrow, Orange-crowned Warbler, and Common Yellowthroat). Productivity was highest for most species in 2010 and 2019, years with high precipitation, and lowest in 2014 and 2018, years with low precipitation. Song Sparrow demonstrated the highest productivity among species and Least Bell’s Vireo had the lowest productivity. Annual adult survival was generally high from 2011 to 2012 and from 2018 to 2019. Bushtit had higher annual survival with lower late winter precipitation. Either temperature or precipitation was associated with productivity for all species except Wrentit, and with survival for all species except Least Bell’s Vireo and Common Yellowthroat. For most species, productivity was positively associated with precipitation, and both productivity and survival were negatively associated with temperature. Other studies have found that higher temperatures led to increased predation by snakes and birds and also increased vector-borne disease transmission, such as West Nile virus. Predicted regional increases in temperature over the next 30 years will likely affect the demographics of these species. The Song Sparrow population increased with higher breeding productivity during the previous year, and the Bushtit population increased with higher annual survival and higher productivity during the previous year. Aside from a possible positive association between survivorship and Common Yellowthroat population growth, productivity and survival rates did not appear to influence population change for other focal species.

California↗

USGS2019

The effects of management practices on grassland birds — An introduction to North American grasslands and the practices used to manage grasslands and grassland birds

The Great Plains of North America is defined as the land mass that encompasses the entire central portion of the North American continent that, at the time of European settlement, was an unbroken expanse of primarily herbaceous vegetation. The Great Plains extend from central Saskatchewan and Alberta to central Mexico and from Indiana to the Rocky Mountains. The expanses of herbaceous vegetation are often referred to as native prairie or native grasslands. Native grasslands share the characteristics of a general uniformity in vegetation structure, dominance by grasses and forbs, a near absence of trees and shrubs, annual precipitation ranging from 25 to 100 centimeters, extreme intra-annual fluctuations in temperature and precipitation, and a flat to rolling topography over which fires can spread. To the west of the Great Plains lie the sagebrush communities of the Great Basin, which extend from British Columbia and Saskatchewan to northern Arizona and New Mexico and from the eastern slopes of the Sierra Nevada and Cascade mountain ranges to western South Dakota. Sagebrush communities share similar characteristics to native grasslands, but their location east of the Rocky Mountains creates a more moderating influence from prevailing westerly winds that affect timing of peak precipitation and growth form of dominant vegetation. Native grasslands and sagebrush communities harbor a diverse array of grassland, wetland, and woodland plant and animal communities that are uniquely adapted to the natural forces of the Great Plains and Great Basin, namely the interactive forces of climate, fire, and grazing. The arrival of European settlers to North America brought profound change to native grassland and sagebrush communities, including the establishment of permanent towns and cities, the proliferation of cropland-based agricultural systems, and the suppression of wildfires. The near extirpation of bison by the 1860s paved the way for dramatic changes in the dominant grazers and a shift in the disturbance patterns that historically influenced vegetation structure. The greatest threat to native grasslands and sagebrush communities in modern times is their loss due to conversion to rowcrop agriculture and to urbanization. Concomitant with habitat loss is a precipitous decline in populations of bird species that evolved with, and are uniquely adapted to, the native grassland and sagebrush habitats. Avian population trends are linked strongly to agricultural land use. Besides outright loss of suitable breeding habitat, agricultural practices affect birds through factors such as pesticide exposure, habitat fragmentation, shifts in predator community composition, and occurrence of brood parasites. Bird populations face other stressors, such as loss of habitat to and behavioral avoidance of urbanized areas, roads, and infrastructure associated with energy production. Despite the many anthropogenic changes to North American grassland and sagebrush communities, some bird species are adaptable and opportunistic in their habitat selection and now utilize one or more human-created habitats. Human-created habitats include pastures, hayfields, agricultural terraces, crop buffer strips, field borders, grassed waterways, fencerows, road rights-of-way, airports, reclaimed coal mines, and planted wildlife cover. Fields of seeded grasslands enrolled in Federal long-term set-aside programs, such as the Conservation Reserve Program in the United States and the Permanent Cover Program in Canada, provide important nesting habitat for grassland bird species. The array of habitats used by birds makes habitat and avian management a complex undertaking, and the scale (for example, local, regional, international) at which management actions can be implemented are such that a universal approach to managing grasslands for the conservation of the entire suite of bird species does not exist. Experienced land managers recognize that it is impossible to manage for all bird species simultaneously, and thus, prioritization is necessary towards those habitats or bird species that the manager or management agency ranks highest for a specific region or management unit. The primary tools available for management are burning, grazing, mowing, herbicide application, and idling, but before choosing a particular practice, a manager will want to consider issues of seasonality, intensity, and frequency. Despite the thousands of studies that are cited in this compendium, much remains unknown about the effects of management practices on bird species. The series of species accounts in this compendium review the current state of knowledge regarding management of grassland and sagebrush bird species and summarize information on the effects of management practices on individual species. The accounts do not give definitive statements on the effects of management practices for any particular species, primarily because there are very few replicated studies in which identical management practices have been applied in the same geographical area with consistent results, which are elements necessary to provide concrete recommendations for the management of a particular species in a particular area. Documentation of the effects of management treatments on individual species through statistically sound methods that incorporate multiple years and locations will further scientists’ and land managers’ knowledge far more than 1–2-year studies that are limited in scope as well as time, but studies of that scope and breadth are rare.

Professional Paper↗

USGS2017

A genetic signature of the evolution of loss of flight in the Galapagos cormorant

INTRODUCTION Changes in the size and proportion of limbs and other structures have played a key role in the evolution of species. One common class of limb modification is recurrent wing reduction and loss of flight in birds. Indeed, Darwin used the occurrence of flightless birds as an argument in favor of his theory of natural selection. Loss of flight has evolved repeatedly and is found among 26 families of birds in 17 different orders. Despite the frequency of these modifications, we have a limited understanding of their underpinnings at the genetic and molecular levels. RATIONALE To better understand the evolution of changes in limb size, we studied a classic case of recent loss of flight in the Galapagos cormorant ( Phalacrocorax harrisi ). Cormorants are large water birds that live in coastal areas or near lakes, and P. harrisi is the only flightless cormorant among approximately 40 extant species. The entire population is distributed along the coastlines of Isabela and Fernandina islands in the Galapagos archipelago. P. harrisi has a pair of short wings, which are smaller than those of any other cormorant. The extreme reduction of the wings and pectoral skeleton observed in P. harrisi is an attractive model for studying the evolution of loss of flight because it occurred very recently; phylogenetic evidence suggests that P. harrisi diverged from its flighted relatives within the past 2 million years. We developed a comparative and predictive genomics approach that uses the genome sequences of P. harrisi and its flighted relatives to find candidate genetic variants that likely contributed to the evolution of loss of flight. RESULTS We sequenced and de novo assembled the whole genomes of P. harrisi and three closely related flighted cormorant species. We identified thousands of coding variants exclusive to P. harrisi and classified them according to their probability of altering protein function based on conservation. Variants most likely to alter protein function were significantly enriched in genes mutated in human skeletal ciliopathies, including Ofd1 , Evc , Wdr34 , and Ift122 . We carried out experiments in Caenorhabditis elegans to confirm that a missense variant present in the Galapagos cormorant IFT122 protein is sufficient to affect ciliary function. The primary cilium is essential for Hedgehog (Hh) signaling in vertebrates, and individuals affected by ciliopathies have small limbs and ribcages, mirroring the phenotype of P. harrisi . We also identified a 4–amino acid deletion in the regulatory domain of Cux1 , a highly conserved transcription factor that has been experimentally shown to regulate limb growth in chicken. The four missing amino acids are perfectly conserved in all birds and mammals sequenced to date. We tested the consequences of this deletion in a chondrogenic cell line and showed that it impairs the ability of CUX1 to transcriptionally up-regulate cilia-related genes (some of which contain function-altering variants in P. harrisi ) and to promote chondrogenic differentiation. Finally, we show that positive selection may have played a role in the fixation of the variants associated with loss of flight in P. harrisi . CONCLUSION Our results indicate that the combined effect of variants in genes necessary for the correct transcriptional regulation and function of the primary cilium likely contributed to the evolution of highly reduced wings and other skeletal adaptations associated with loss of flight in P. harrisi . Our approach may be generally useful for identification of variants underlying evolutionary novelty from genomes of closely related species.

Science↗

USGS2004

On the use of capture-recapture models in mist-net studies

Capture-recapture models provide a statistical framework for estimating population parameters from mist-net data. Although Cormack-Jolly-Seber and related models have recently been used to estimate survival rates of birds sampled with mist nets, we believe that the full potential for use of capture-recapture models has not been realized by many researchers involved in mist-net studies. We present a brief discussion of the overall framework for estimation using capture-recapture methods, and review several areas in which recent statistical methods can be, but generally have not yet been, applied to mist-net studies. These areas include estimation of (I) rates of movement among areas; (2) survival rates in the presence of transients: (3) population sizes or migrating birds: (4) proportion of birds alive but not present at a breeding site (one definition of proportion of nonbreeding birds in a population): (5) population change and recruitment: and (6) species richness. Using these models will avoid the possible bias associated with use of indices. and provide statistically valid variance estimates and inference.

Book chapter↗

USGS2011

An individual and a sex odor signature in kittiwakes? Study of the semiochemical composition of preen secretion and preen down feathers

The importance of olfaction in birds' social behavior has long been denied. Avian chemical signaling has thus been relatively unexplored. The black-legged kittiwake provides a particularly appropriate model for investigating this topic. Kittiwakes preferentially mate with genetically dissimilar individuals, but the cues used to assess genetic characteristics remain unknown. As in other vertebrates, their body odors may carry individual and sexual signatures thus potentially reliably signaling individual genetic makeup. Here, we test whether body odors in preen gland secretion and preen down feathers in kittiwakes may provide a sex and an individual signature. Using gas chromatography and mass spectrometry, we found that male and female odors differ quantitatively, suggesting that scent may be one of the multiple cues used by birds to discriminate between sexes. We further detected an individual signature in the volatile and nonvolatile fractions of preen secretion and preen down feathers. These results suggest that kittiwake body odor may function as a signal associated with mate recognition. It further suggests that preen odor might broadcast the genetic makeup of individuals, and could be used in mate choice to assess the genetic compatibility of potential mates.

Naturwissenschaften↗

USGS2002

Double sampling to estimate density and population trends in birds

We present a method for estimating density of nesting birds based on double sampling. The approach involves surveying a large sample of plots using a rapid method such as uncorrected point counts, variable circular plot counts, or the recently suggested double-observer method. A subsample of those plots is also surveyed using intensive methods to determine actual density. The ratio of the mean count on those plots (using the rapid method) to the mean actual density (as determined by the intensive searches) is used to adjust results from the rapid method. The approach works well when results from the rapid method are highly correlated with actual density. We illustrate the method with three years of shorebird surveys from the tundra in northern Alaska. In the rapid method, surveyors covered ~10 ha h -1 and surveyed each plot a single time. The intensive surveys involved three thorough searches, required ~3 h ha -1 , and took 20% of the study effort. Surveyors using the rapid method detected an average of 79% of birds present. That detection ratio was used to convert the index obtained in the rapid method into an essentially unbiased estimate of density. Trends estimated from several years of data would also be essentially unbiased. Other advantages of double sampling are that (1) the rapid method can be changed as new methods become available, (2) domains can be compared even if detection rates differ, (3) total population size can be estimated, and (4) valuable ancillary information (e.g. nest success) can be obtained on intensive plots with little additional effort. We suggest that double sampling be used to test the assumption that rapid methods, such as variable circular plot and double-observer methods, yield density estimates that are essentially unbiased. The feasibility of implementing double sampling in a range of habitats needs to be evaluated.

The Auk↗

USGS2017

Validation of NEXRAD data and models of bird migration stopover sites in the Northeast U.S.

The national network of weather surveillance radars (NEXRAD) detects birds in flight, and has proven to be a useful remote-sensing tool for ornithological study. We used data collected during Fall 2008 to 2014 by 16 NEXRAD and four terminal Doppler weather radars (TDWR) in the northeastern U.S. to map and study the spatial distribution of landbirds shortly after they leave daytime stopover sites to embark on nocturnal migratory flights. Given observed variability in the precise timing of migratory exodus, we developed a new method to sample the onset of migration at the point of maximum rate of increase in bird densities aloft to consistently sample exodus across radars and days. The mean linear trend in aggregate stopover densities of migrants indicated a 4% decline per year from the 2008 baseline density (29% decline over the seven years). Regionally, coastal Virginia and Maine had the steepest declines. The steepest increases in migrant densities across years occurred within the Delmarva Peninsula and in coastal Connecticut. We used NEXRAD observations to develop models to predict potentially important stopover sites throughout USFWS Region 5. Observed NEXRAD data were positively correlated to observations from TDWR and NASA’s S-Band Dual-Polarimetric Radar (NPOL), though not strongly. Predicted densities increased with increasing hardwood cover across multiple scales and with vegetation productivity. Contrastingly, predicted densities decreased with increasing agricultural, emergent marsh and coniferous land cover, but did not change with fraction of urban cover. Stopover density increased closer to bright areas and the Atlantic coast. Moreover, interactive effects indicated that migrants were more concentrated in forested areas that were both brightly lit and near the Atlantic coast. Large areas of predicted regionally important stopover sites were located along the coastlines of Maine, Long Island Sound, New Jersey, the lower Delmarva Peninsula, within the Adirondack Mountains, Catskill Mountains, and eastern Virginia. We also created maps of classified stopover use during bimonthly periods and at multiple-scales. Migrant densities peaked along the Adirondack Mountains early in September, and along the Atlantic coast in late September with the passage of Neotropical migrants. Stopover densities peaked in the most northern extent of Maine and New England States in late October with the departure of temperate migrants. Ground surveys conducted at 48 forested sites within the Delmarva Peninsula and Tidewater Virginia during Fall 2013 and 2014 revealed that nocturnal migrant densities pooled across species and for 14 individual species, after accounting for temporal phenology in their passage timing, were related to factors operating at multiple scales including food resources (primarily arthropod abundance in understory) and understory shrub density at a patch scale, and latitude and proximity to the Atlantic coast at a regional scale. We integrated field survey and radar data to estimate relative stopover duration and to identify stopover functional types among 45 sites that included data from a past study near the Gulf of Mexico. We identified four functional types spanning the gradient of short rest stops to refueling stops with variable duration of stopover in relation to food abundance. The Mid-Atlantic sites were dominated by rest stops near coastal areas and lacked quick refueling stops due to low overall food abundance. The maps and ecological understanding produced can help inform conservation planning to protect and enhance stopover sites for migratory landbirds in the future.

Report↗

USGS2012

A modified night-netting technique for recapturing quail

Difficulties in recapturing radiomarked birds often prevent wildlife researchers from replacing transmitters and continuing to collect data over long time periods. We developed an effective, inexpensive capture technique for radiomarked mountain quail (Oreortyx pictus). Twenty-three of 25 mountain quail in south-central Idaho, USA, in 2006 and 2007 were recaptured for transmitter replacement. This technique will provide researchers with an opportunity to recapture relatively small birds, particularly those in dense vegetation, to help conduct long-term studies.

Wildlife Society Bulletin↗

USGS1987

Effects of oral doses of fluoride on nestling European starlings

Nestling European starlings ( Sturnus vulgaris ), raised and fed by free-living adults, were given daily oral doses of either distilled water, 193 mg sodium as Na 2 CO 3 per kg of body weight (sodium control group), or 6, 10, 13, 17, 23, 30, 40, 80, 160 mg of the fluoride ion as NaF in distilled water per kg of body weight (mg/kg). Dosing began when nestlings were 24–48 hr old and continued for 16 days. The 24-hr LD 50 of fluoride for day-old starlings was 50 mg/kg. The 16-day LD 50 was 17 mg/kg. The sodium control group did not differ from the water control group with respect to any of the measured variables. Growth rates were significantly reduced in the 13 and 17 mg of fluoride/kg groups; weights of birds given higher dose levels were omitted from growth comparisons because of high, fluoride-induced mortality. Although prefledging weights for the 10, 13, and 17 mg of fluoride/kg groups averaged 3.6 to 8.6% less than controls at 17 days, this difference was not significant. Feather and bone growth of the fluoride and control groups were not different, except for keel length measured at 17 days of age which averaged less in the fluoride groups. Liver and spleen weights were not affected by fluoride treatments. No histological damage related to fluoride treatments was found in liver, spleen, or kidney. The logarithm of bone fluoride and magnesium concentration increased with the logarithm of increasing fluoride treatment levels and were significantly correlated with each other. Fluoride treatments had no effect on percent calcium or phosphorus in bone or plasma alkaline phosphatase activity. Oral doses of fluoride appear to be more toxic than equivalent dietary levels. Most birds probably acquire fluoride through their diet. Therefore, the results of the study may overstimate the potential effects of fluorides on songbirds living in fluoride-contaminated environments.

Archives of Environmental Contamination and Toxico↗

USGS2004

Differential parasitism of seed-feeding Cydia (Lepidoptera: Tortricidae) by native and alien wasp species relative to elevation in subalpine Sophora (Fabaceae) forests on Mauna Kea, Hawaii

Alien parasitic wasps, including accidental introductions and purposefully released biological control agents, have been implicated in the decline of native Hawaiian Lepidoptera. Understanding the potential impacts of alien wasps requires knowledge of ecological parameters that influence parasitism rates for species in their new environment. Sophora seed-feeding Cydia spp. (Lepidoptera: Tortricidae) were surveyed for larval parasitoids to determine how native and alien wasps are partitioned over an elevation gradient (2200-2800 m) on Hawaii Island, Hawaii. Parasitism rate of native Euderus metallicus (Eulophidae) increased with increased elevation, while parasitism rate by immigrant Calliephialtes grapholithae (Ichneumonidae) decreased. Parasitism by Pristomerus hawaiiensis (Ichneumonidae), origins uncertain, also decreased with increased elevation. Two other species, Diadegma blackburni (Ichneumonidae), origins uncertain, and Brasema cushmani (Eupelmidae), a purposefully introduced biological control agent for pepper weevil, did not vary significantly with elevation. Results are contrasted with a previous study of this system with implications for the conservation of an endangered bird species that feed on Cydia larvae. Interpretation of results is hindered by lack of knowledge of autecology of moths and wasps, origins, phylogeny, systematics, competitive ability, and physiological limitations of each wasp species. These factors should be incorporated into risk analysis for biological control introductions and invasive species programs. ?? 2004 Kluwer Academic Publishers.

Journal of Insect Conservation↗

USGS2009

Impacts of experimentally increased foraging effort on the family: offspring sex matters

We examined how short-term impacts of experimentally increased foraging effort by one parent reverberate around the family in a monomorphic seabird (little auk, Alle alle), and whether these effects depend on offspring sex. In many species, more effort is required to rear sons successfully than daughters. However, undernourishment may have stronger adverse consequences for male offspring, which could result in a lower fitness benefit of additional parental effort when rearing a son. We tested two alternative hypotheses concerning the responses of partners to handicapping parents via feather clipping: partners rearing a son are (1) more willing or able to compensate for the reduced contribution of their mate, or (2) less willing or able to compensate, compared to those rearing a daughter. Hypothesis 1 predicts that sons will be no more adversely affected than daughters, and the impact on parents will be greater when rearing a son. Hypothesis 2 predicts that sons will be more adversely affected than daughters, and parents raising a son less affected. Although experimental chicks of both sexes fledged in poorer condition than controls, sons attained higher mass and more rapid growth than daughters in both groups. Clipped parents lost a similar proportion of their initial mass regardless of chick sex, whereas partners of clipped birds lost more mass when rearing a son. These results support hypothesis 1: impacts of increased foraging effort by one parent were felt by offspring, regardless of their sex, and by the partners of manipulated birds, particularly when the offspring was male. ?? 2009 The Association for the Study of Animal Behaviour.

Animal Behaviour↗

USGS2002

A case for using Plethodontid salamanders for monitoring biodiversity and ecosystem integrity of North American forests

Terrestrial salamanders of the family Plethodontidae have unique attributes that make them excellent indicators of biodiversity and ecosystem integrity in forested habitats. Their longevity, small territory size, site fidelity, sensitivity to natural and anthropogenic perturbations, tendency to occur in high densities, and low sampling costs mean that counts of plethodontid salamanders provide numerous advantages over counts of other North American forest organisms for indicating environmental change. Furthermore, they are tightly linked physiologically to microclimatic and successional processes that influence the distribution and abundance of numerous other hydrophilic but difficult-to-study forest-dwelling plants and animals. Ecosystem processes such as moisture cycling, food-web dynamics, and succession, with their related structural and microclimatic variability, all affect forest biodiversity and have been shown to affect salamander populations as well. We determined the variability associated with sampling for plethodontid salamanders by estimating the coefficient of variation (CV ) from available time-series data. The median coefficient of variation indicated that variation in counts of individuals among studies was much lower in plethodontids (27%) than in lepidoptera (93%), passerine birds (57%), small mammals (69%), or other amphibians (37–46%), which means plethodontid salamanders provide an important statistical advantage over other species for monitoring long-term forest health.

Conservation Biology↗

USGS2022

Demographic implications of lead poisoning for eagles across North America

Lead poisoning occurs worldwide in populations of predatory birds, but exposure rates and population impacts are known only from regional studies. We evaluated the lead exposure of 1210 bald and golden eagles from 38 US states across North America, including 620 live eagles. We detected unexpectedly high frequencies of lead poisoning of eagles, both chronic (46 to 47% of bald and golden eagles, as measured in bone) and acute (27 to 33% of bald eagles and 7 to 35% of golden eagles, as measured in liver, blood, and feathers). Frequency of lead poisoning was influenced by age and, for bald eagles, by region and season. Continent-wide demographic modeling suggests that poisoning at this level suppresses population growth rates for bald eagles by 3.8% (95% confidence interval: 2.5%, 5.4%) and for golden eagles by 0.8% (0.7%, 0.9%). Lead poisoning is an underappreciated but important constraint on continent-wide populations of these iconic protected species.

Science↗

USGS2015

Cyclic avian mass mortality in the northeastern United States is associated with a novel orthomyxovirus

Since 1998, cyclic mortality events in common eiders ( Somateria mollissima ), numbering in the hundreds to thousands of dead birds, have been documented along the coast of Cape Cod, Massachusetts, USA. Although longitudinal disease investigations have uncovered potential contributing factors responsible for these outbreaks, detecting a primary etiological agent has proven enigmatic. Here we identify a novel orthomyxovirus, tentatively named Wellfleet Bay virus (WFBV), as a potential causative agent of these outbreaks. Genomic analysis of WFBV revealed that it is most closely related to members of the Quaranjavirus genus within the family Orthomyxoviridae . Similar to other members of the genus, WFBV contains an alphabaculovirus gp64-like glycoprotein, which was demonstrated to have fusion activity, and also tentatively suggests that ticks (and/or insects) may vector the virus in nature. However, in addition to the six RNA segments encoding the prototypical structural proteins identified in other quaranjaviruses, a previously unknown RNA segment (segment 7) encoding a novel protein designated as VP7 was discovered in WFBV. Although WFBV shows low to moderate levels of sequence similarity to Quaranfil virus and Johnston Atoll virus , the original members of the Quaranjavirus genus, additional antigenic and genetic analyses demonstrated that it is closely related to the recently identified Cygnet River virus (CyRV) from South Australia, suggesting that WFBV and CyRV may be geographic variants of the same virus. Although the identification of WFBV in part may resolve the enigma of these mass mortality events, the details of the ecology and epidemiology of the virus remain to be determined. Importance The emergence or reemergence of viral pathogens resulting in large-scale outbreaks of disease in humans and/or animals is one of the most important challenges facing biomedicine. For example, understanding how orthomyxoviruses such as novel influenza A virus reassortants and/or mutants emerge to cause epidemic or pandemic disease is at the forefront of current global health concerns. Here we describe the emergence of a novel orthomyxovirus, Wellfleet Bay virus (WFBV), which has been associated with cyclic large-scale bird die-offs in the northeastern United States. This initial characterization study provides a foundation for further research into the evolution, epidemiology, and ecology of newly emerging orthomyxoviruses, such as WFBV, and their potential impacts on animal and/or human health.

Massachusets↗