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USGS2023

Site fidelity of migratory shorebirds facing habitat deterioration: Insights from satellite tracking and mark-resighting

Background Site fidelity, the tendency to return to a previously visited site, is commonly observed in migratory birds. This behaviour would be advantageous if birds returning to the same site, benefit from their previous knowledge about local resources. However, when habitat quality declines at a site over time, birds with lower site fidelity might benefit from a tendency to move to sites with better habitats. As a first step towards understanding the influence of site fidelity on how animals cope with habitat deterioration, here we describe site fidelity variation in two species of sympatric migratory shorebirds (Bar-tailed Godwits Limosa lapponica and Great Knots Calidris tenuirostris ). Both species are being impacted by the rapid loss and deterioration of intertidal habitats in the Yellow Sea where they fuel up during their annual long-distance migrations. Methods Using satellite tracking and mark-resighting data, we measured site fidelity in the non-breeding (austral summer) and migration periods, during which both species live and co-occur in Northwest Australia and the Yellow Sea, respectively. Results Site fidelity was generally high in both species, with the majority of individuals using only one site during the non-breeding season and revisiting the same sites during migration. Nevertheless, Great Knots did exhibit lower site fidelity than Bar-tailed Godwits in both Northwest Australia and the Yellow Sea across data types. Conclusions Great Knots encountered substantial habitat deterioration just before and during our study period but show the same rate of decline in population size and individual survival as the less habitat-impacted Bar-tailed Godwits. This suggests that the lower site fidelity of Great Knots might have helped them to cope with the habitat changes. Future studies on movement patterns and their consequences under different environmental conditions by individuals with different degrees of site fidelity could help broaden our understanding of how species might react to, and recover from, local habitat deterioration.

Movement Ecology↗

USGS2016

Experience drives innovation of new migration patterns of whooping cranes in response to global change

Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Spatial changes in migration have been related to long-term temperature trends, but the intrinsic mechanisms by which migratory species adapt to environmental change remain largely unexplored. We show that, for a long-lived social species, older birds with more experience are critical for innovating new migration behaviours. Groups containing older, more experienced individuals establish new overwintering sites closer to the breeding grounds, leading to a rapid population-level shift in migration patterns. Furthermore, these new overwintering sites are in areas where changes in climate have increased temperatures and where food availability from agriculture is high, creating favourable conditions for overwintering. Our results reveal that the age structure of populations is critical for the behavioural mechanisms that allow species to adapt to global change, particularly for long-lived animals, where changes in behaviour can occur faster than evolution.

Nature Communications↗

USGS2018

Evaluation of acoustic telemetry grids for determining aquatic animal movement and survival

Acoustic telemetry studies have frequently prioritized linear configurations of hydrophone receivers, such as perpendicular from shorelines or across rivers, to detect the presence of tagged aquatic animals. This approach introduces unknown bias when receivers are stationed for convenience at geographic bottlenecks (e.g., at the mouth of an embayment or between islands) as opposed to deployments following a statistical sampling design. We evaluated two-dimensional acoustic receiver arrays (grids: receivers spread uniformly across space) as an alternative approach to provide estimates of survival, movement, and habitat use. Performance of variably-spaced receiver grids (5–25 km spacing) was evaluated by simulating (1) animal tracks as correlated random walks (speed: 0.1–0.9 m/s; turning angle standard deviation: 5–30 degrees); (2) variable tag transmission intervals along each track (nominal delay: 15–300 seconds); and (3) probability of detection of each transmission based on logistic detection range curves (midpoint: 200–1500 m). From simulations, we quantified i) time between successive detections on any receiver (detection time), ii) time between successive detections on different receivers (transit time), and iii) distance between successive detections on different receivers (transit distance). In the most restrictive detection range scenario (200 m), the 95 th percentile of transit time was 3.2 days at 5 km grid spacing, 5.7 days at 7 km, and 15.2 days at 25 km; for the 1500 m detection range scenario, it was 0.1 days at 5 km, 0.5 days at 7 km, and 10.8 days at 25 km. These values represented upper bounds on the expected maximum time that an animal could go undetected. Comparison of the simulations with pilot studies on three fishes (walleye Sander vitreus , common carp Cyprinus carpio , and channel catfish Ictalurus punctatus ) from two independent large lake ecosystems (lakes Erie and Winnipeg) revealed shorter detection and transit times than what simulations predicted. By spreading effort uniformly across space, grids can improve understanding of fish migration over the commonly employed receiver line approach, but at increased time cost for maintaining grids.

Methods in Ecology and Evolution↗

USGS2021

Breeding at higher latitude is associated with higher photoperiodic threshold and delayed reproductive development in a songbird

Many seasonally breeding animals exhibit a threshold day length (critical photoperiod; CPP) for gonadal growth, and populations breeding at higher latitudes typically have a higher CPP. Much less is known about latitudinal variation in CPP in migratory population that winter away from their breeding range and must time their reproduction to match favorable conditions at their destination. To address the relationship between migration, breeding latitude, and CPP, we held two closely related songbird populations in a common environment. One population is resident ( Junco hyemalis carolinensis ), the other winters in sympatry with the residents but migrates north to breed ( Junco hyemalis hyemalis ). We gradually increased photoperiod and measured indices of readiness to migrate (fat score, body mass) and breed (cloacal protuberance volume, baseline testosterone, and gonadotropin releasing hormone challenged testosterone). To estimate breeding latitude, we measured hydrogen isotopes in feathers grown the preceding year. As we predicted, we found a higher CPP in migrants than residents, and a higher CPP among migrants deriving from higher as opposed to lower latitudes. Migrants also terminated breeding earlier than residents, indicating a shorter breeding season. To our knowledge, this is a first demonstration of latitudinal variation in CPP-dependent reproductive timing in bird populations that co-exist in the non-breeding season but breed at different latitudes. We conclude that bird populations appear to exhibit local adaptation in reproductive timing by relying on differential CPP response that is predictive of future conditions on the breeding ground.

Indiana↗

USGS2025

Not all who meander are lost: Migrating sea lamprey follow river thalwegs to facilitate safe and efficient passage upstream

Efficient navigation is crucial for the reproductive success of many migratory species, often driven by competing pressures to conserve energy and reduce predation risk. Little is known about how non-homing species achieve this balance. We show that sea lamprey ( Petromyzon marinus ), an ancient extant vertebrate, uses persistent patterns in hydro-geomorphology to quickly and efficiently navigate through complex ecosystems. Hydrodynamic flow models coupled with bathymetric mapping and fine-scale acoustic telemetry revealed movement paths that tracked thalweg scour channels, which are often the deepest and fastest-flowing sections of a river. These paths allow rapid and efficient upstream migration and suggest the existence of a bathymetric highway system. Near-substrate swimming along this path resulted in a median of 5.8% energy savings while also promoting improved safety from nocturnally active predators. We hypothesize sea lampreys use hydrostatic pressure-guided rheotaxis to achieve this navigation. It is likely this tactic relies on sensory information from the animal's primitive lateral line and perhaps the inner ear. Insights from this study can be used to redesign conservation practices to achieve improved control where the animal is invasive and improved fish passage within its native range.

Michigan↗

USGS2017

Quantifying animal movement for caching foragers: the path identification index (PII) and cougars, Puma concolor

Relocation studies of animal movement have focused on directed versus area restricted movement, which rely on correlations between step-length and turn angles, along with a degree of stationarity through time to define behavioral states. Although these approaches may work well for grazing foraging strategies in a patchy landscape, species that do not spend a significant amount of time searching out and gathering small dispersed food items, but instead feed for short periods on large, concentrated sources or cache food result in movements that maybe difficult to analyze using turning and velocity alone. We use GPS telemetry collected from a prey-caching predator, the cougar (Puma concolor), to test whether adding additional movement metrics capturing site recursion, to the more traditional velocity and turning, improve the ability to identify behaviors. We evaluated our movement index’s ability to identify behaviors using field investigations. We further tested for statistical stationarity across behaviors for use of topographic view-sheds. We found little correlation between turn angle, velocity, tortuosity, and site fidelity and combined them into a movement index used to identify movement paths (temporally autocorrelated movements) related to fast directed movements (taxis), area restricted movements (search), and prey caching (foraging). Changes in the frequency and duration of these movements were helpful for identifying seasonal activities such as migration and denning in females. Comparison of field investigations of cougar activities to behavioral classes defined using the movement index and found an overall classification accuracy of 81%. Changes in behaviors resulted in changes in how cougars used topographic view-sheds, showing statistical non-stationarity over time. The movement index shows promise for identifying behaviors in species that frequently return to specific locations such as food caches, watering holes, or dens, and highlights the role memory and cognitive abilities may play in determining animal movements. With the addition of measures capturing site recursion the temporal structure in movements of a caching forager was revealed.

Movement Ecology↗

USGS2003

Ecosystem-level consequences of migratory faunal depletion caused by dams

Humans have been damming rivers for millennia, and our more ambitious efforts over the past century have arguably altered river ecosystems more extensively than any other anthropogenic activity. Effects of damming on river biota include decimation of migratory fauna (e.g., diadromous and potamodromous fishes and crustaceans), lost fisheries, and imperilment of obligate riverine taxa. Although effects of dams on biota have been widely documented, ecosystem-level consequences of faunal depletion caused by dams are only beginning to be appreciated. We discuss consequences to river ecosystems of altering distributions and abundances of migratory fauna, which often provide trophic subsidies and may strongly influence the structure of local habitats and communities. It is well documented that anadromous fishes can provide a major input of nutrients and energy to freshwater systems when spawning adults return from the sea. Other less-studied taxa that migrate between distinct portions of riverine systems (e.g., acipencerids, catostomids, and prochilodontids) may similarly provide trophic transfers within undammed river systems, in addition to modifying local communities and habitats through feeding and spawning activities. Experimental faunal exclusions have demonstrated strong potential effects of some amphidromous shrimps and potamodromous fishes on benthic organic matter and algal and invertebrate communities. Depletion of these animals above dams is likely to significantly affect ecosystem processes such as primary production and detrital processing. The decline of freshwater mussels isolated by dams from their migratory fish hosts has likely lowered stream productivity, nutrient retention and benthic stability. Greater focus on effects of dams on ecosystem processes, as mediated by faunal change, would improve our ability to assess the costs and benefits of future river management strategies.

Book chapter↗

USGS2018

Migratory hummingbirds make their own rules: The decision to resume migration along a barrier

Knowing how naïve migrants respond to intrinsic and extrinsic factors experienced en route will allow a more thorough understanding of the endogenous migratory programme. To understand how inexperienced individuals respond to ecological features, we tracked the migratory departures of juvenile ruby-throated hummingbirds, Archilochus colubris , one of the smallest (∼ 3 g) and least-studied migrants, along the Gulf of Mexico during southbound migration using an international automated radiotelemetry system. The recent miniaturization of radiotags provides a novel method to track one of the smallest migratory birds, rendering the first information on departure decisions of known hummingbirds in relation to an ecological barrier. Using weather conditions and individual attributes, we also determined which factors influenced the time and direction of departure from a coastal stopover site. Most migrants (83%) departed in the morning, and daily departure time was only influenced by stopover duration, the amount of time spent at a stopover site. The majority (77%) of departure orientations paralleled the coastline, and we found little influence of any factor on departure direction. Our results reveal that (1) juvenile hummingbirds departing coastal Alabama move in a direction indicative of a circum-Gulf path during southbound migration and (2) departure decisions support a fly-and-forage strategy in which hummingbirds likely take advantage of resources along the coast while moving towards their destination.

Gulf of Mexico↗

USGS2023

Integrated science strategy for assessing and monitoring water availability and migratory birds for terminal lakes across the Great Basin, United States

Executive Summary In 2022, the U.S. Geological Survey (USGS) established the Saline Lake Ecosystems Integrated Water Availability Assessment (IWAAs) to monitor and assess the hydrology of terminal lakes in the Great Basin and the migratory birds and other wildlife dependent on those habitats. Scientists from across the USGS (with specialties in water quantity, water quality, limnology, avian biology, data science, landscape ecology, and science communication) formed the Saline Lake Ecosystems IWAAs Team. The team has developed this regional strategic science plan to guide data collection and assessment activities at terminal lakes in the Great Basin. The U.S. Congress requested the USGS to establish the Saline Lake Ecosystems IWAAs in response to historically low water levels at terminal lakes and associated wetlands across the Great Basin. Not all Great Basin terminal lakes have high salinity; however, all terminal lakes occur in endorheic, closed, basins with no surface-water outflow. Low lake levels across the Great Basin are the result of increased water use for agriculture and municipalities, drought conditions, and a warming climate. Great Basin terminal lake water extents have decreased by as much as 90 percent over the last 150 years, and terminal lake wetlands have decreased in area by as much as 47 percent since 1984. Lake elevations and wetland areas are primarily supported by freshwater inputs from snowmelt feeding upgradient rivers, streams, and springs. These freshwater inputs have been severely reduced because of continued and increased surface-water diversions and surface-water capture through groundwater pumping for agriculture, mining, and public supply as well as unprecedented drought conditions and warming temperatures related to climate change. Water quality, specifically salinity, is highly variable for terminal lakes of the Great Basin, and this variability is a result of the balance between freshwater inflow and evaporation. Variability of salinity at each of the terminal lakes can be affected by lake morphology, hydrogeologic features of the basin, annual variability in weather patterns, and changes in upgradient water use. Hypersaline terminal lakes provide abundant food resources such as brine shrimp and brine flies that support nesting and migrating birds. The density and composition of invertebrates are closely tied to lake salinity. Increased salinity can exceed the tolerance of invertebrates, severely limiting their biomass. In contrast, decreased salinity can lead to altered invertebrate community composition, reducing the abundance of optimal avian prey resources. Great Basin terminal lake ecosystems, including open-water and adjacent aquatic and terrestrial environments, provide resources necessary to sustain many animal populations throughout the year. Although a variety of taxa use terminal lakes, these ecosystems are of acute importance for the millions of migratory waterbirds (for example, shorebirds, wading birds, and waterfowl) dependent on the network of terminal lakes and their associated wetlands. Migratory birds transiting the Pacific and Central Flyways use Great Basin terminal lake ecosystems throughout the year to feed, nest, and transit between wintering and breeding ranges. As such, successful conservation of birds and their habitats requires coordinated management of water and habitats across the Great Basin network of terminal lakes and wetlands. The linkages between water availability and ecosystem vulnerability of terminal lakes in the Great Basin are not well understood. The vulnerability of terminal lakes is related to the factors driving change and adaptive capacity of the lake ecosystem. Saline lake ecosystems are vulnerable when changes in water quantity affect ecosystem function. Water quantity affects salinity, which affects food webs and habitat; these linkages can be investigated with water-quality and food web monitoring. Water quantity also affects inundated habitat, which can be quantified through remote sensing. It is necessary to quantify hydroclimatic and water use controls on water availability to terminal lakes to assess the response of the ecosystems. Remotely sensed data can provide a broad-scale and long-term synoptic view of terminal lake hydrologic characteristics, but ground observations are required to interpret changes in water quality and ecological functions. Some terminal lake basins have ongoing monitoring and modeling efforts within the Great Basin (for example, Great Salt Lake, Carson River Basin), yet most monitoring locations are hydrologically upgradient and too far away from lake inflows to provide an accurate assessment of hydrological trends for the lake ecosystems. Other terminal lakes have no long-term hydrological monitoring in their respective watersheds (for example, Lake Abert). Ecological data collection in the Great Basin is also insufficient to understand how many birds exist on the landscape, how birds use the mosaic of terminal-lake habitats as an interconnected system, and how Great Basin terminal lakes are linked to the larger continental system of the Pacific and Central Flyways. Across agencies and organizations, tracking bird movement, abundance, and diversity is inconsistent, with some lakes having once- or twice-a-year bird survey efforts and a few locations having more intensive ecological data-gathering efforts (for example, Great Salt Lake, Lake Abert). Bridging hydrological and ecological information gaps will improve understanding of the trends in water supply and water quality, habitat availability and usage, and impacts on vulnerable waterbird species, all of which would be used by managers in coordinated conservation of this unique network of terminal-lake habitats. The terminal lakes of the Great Basin are part of the Basin and Range physiographic province that extends from the Colorado Plateau on the east to the Sierra Nevada on the west, and from the Snake River Plain on the north to the Garlock fault and the Mojave block on the south. The Great Basin is larger than 650,000 square kilometers and encompasses most of the State of Nevada but also extends to western Utah, eastern California, southeastern Idaho, southwestern Wyoming, and southeastern Oregon. The climate is arid to semiarid with a hydrologic regime that is snowmelt dominated, providing as much as 75 percent of total annual runoff for the region. Terminal lakes of the Great Basin occupy the lowest areas of closed (endorheic) drainage basins, such that lake levels and water quality respond rapidly to surface-water inflow. Terminal lakes provide local and regional economic value to the States in the Great Basin, including mineral extraction, aquaculture, public works, and recreational uses. As an example, assessments of Great Salt Lake’s ecological health and economic impact find hemispheric importance for the former and regional importance for the latter. Great Salt Lake creates about 7,000 jobs and $2 billion of economic output per year, most of which would be lost with further declines in lake level. The objectives of this Science Strategy are threefold: (1) to identify how changing water availability affects the quality, diversity, and abundance of habitats supporting continental waterbird populations; (2) to highlight the scientific monitoring and assessment needs of Great Basin terminal lakes; and (3) to support coordinated management and conservation actions to benefit those ecosystems, migratory birds, and other wildlife. There are long-term hydrological, ecological, and societal challenges associated with terminal lakes ecosystems in the Great Basin. This Science Strategy benefits partners by providing a conceptual model, nested at different spatial extents, that identifies key scientific information needs to inform coordinated implementation of management and conservation plans within and among hydrologic basins to address these complex challenges.

California, Idaho, Nevada, Oregon, Utah, Wyoming↗

USGS2008

Trichinella murrelli in scavenging mammals from south-central Wisconsin, USA

Tissues and serum from 59 raccoons (Procyon lotor), 42 coyotes (Canis latrans), and seven Striped Skunks (Mephitis mephitis) collected in Dane and Iowa Counties, Wisconsin, USA, between October 2005 and March 2006 were microscopically and serologically examined for the presence of Trichinella spp. Encapsulated larvae were found on compression slides prepared from tongue tissues from a few animals. Complete tissue digestion of tongues revealed that 19% of the raccoons, 26% of the coyotes, and none of the seven skunks tested were infected with Trichinella spp. Cats were subsequently experimentally infected by feeding them the raccoon tissues containing muscle larvae, and muscle larvae isolated from the collected tongues were experimentally transmitted to mice. Multiplex polymerase chain reaction analysis of the isolated muscle larvae demonstrated two distinct bands migrating at 127 base pairs (bp) and 316 bp in all samples, which together are diagnostic for Trichinella murrelli; the isolates were assigned Istituto Superiore di Sanita (ISS) codes ISS1656 through ISS1667, and ISS1708 through ISS1710 by the International Trichinella Reference Centre. These findings extend the geographic range of T. murrelli into Wisconsin, USA. ?? Wildlife Disease Association 2008.

Journal of Wildlife Diseases↗

USGS2022

Using piecewise regression to identify biological phenomena in biotelemetry datasets

1. Technological advances in the field of animal tracking have greatly expanded the potential to remotely monitor animals, opening the door to exploring how animals shift their behavior over time or respond to external stimuli. A wide variety of animal-borne sensors can provide information on an animal’s location, movement characteristics, external environmental conditions, and internal physiological status. 2. Here, we demonstrate how piecewise regression can be used to identify the presence and timing of potential shifts in a variety of biological responses using GPS telemetry and other biologging data streams. Different biological latent states can be inferred by partitioning a time-series into multiple segments based on changes in modeled responses (e.g., their mean, variance, trend, degree of autocorrelation) and specifying a unique model structure for each interval. 3. We provide six example applications highlighting a variety of taxonomic species, data streams, timescales and biological phenomena. These examples include a short-term behavioural response (flee and return) by a trumpeter swan Cygnus buccinator following a GPS collar deployment; remote identification of parturition based on movements by a pregnant moose Alces alces ; a physiological response (spike in heart-rate) in a black bear Ursus americanus to a stressful stimulus(presence of a drone); a mortality event of a trumpeter swan signalled by changes in collar temperature and overall dynamic body acceleration; an unsupervised method for identifying the onset, return, duration and staging use of sandhill crane Antigone canadensis migration; and estimation of the transition between incubation and brood-rearing (i.e. hatching) for a breeding trumpeter swan. 4. We implement analyses using the MCP package in R, which provides functionality for specifying and fitting a wide variety of user-defined model structures in a Bayesian framework and methods for assessing and comparing models using information criteria and cross-validation measures.

Journal of Animal Ecology↗

USGS1965

Sex ratios and sexual dimorphism among recently transformed sea lampreys, Petromyzon marinus Linnaeus

The sex, length, and weight were determined of nearly all recently transformed sea lampreys migrating downstream in the Carp Lake River, Michigan, in the fall, winter, and spring of 1960-61. Similar data were collected from samples of an earlier run in the Carp Lake River and of runs in three other tributaries of Lakes Huron and Michigan. The sex ratio of the 1960-61 migrants in the Carp Lake River was 324 males:100 females. Sex ratios of migrants in the other runs varied from 77 to 86 males:100 females. The high proportion of males in the 1960-61 run in the Carp Lake River is attributed to the effective prevention of recruitment of sea lampreys in the river and transformation of the females at an earlier age than is characteristic of the males. A near equal sex ratio among recently transformed migrants is considered normal for the species. The sex composition of a run changed during the period of migration. The proportion of males among the migrants was greatest at the beginning of the run and declined steadily thereafter. The average size was smaller for males than for females. Differences in the mean lengths and weights of the sexes were statistically significant. The length-weight relation differed for the sexes and showed a slower rate of increase of weight with increase in length than is characteristic of other stages of the animals' life cycle. Seasonal changes in the length-weight relation had a trend toward lower weights among the migrants coming downstream in the later months of the run.

Journal of the Fisheries Research Board of Canada↗

USGS2017

Mechanisms associated with an advance in the timing of seasonal reproduction in an urban songbird

The colonization of urban environments by animals is often accompanied by earlier breeding and associated changes in seasonal schedules. Accelerated timing of seasonal reproduction in derived urban populations is a potential cause of evolutionary divergence from ancestral populations if differences in physiological processes that regulate reproductive timing become fixed over time. We compared reproductive development in free-living and captive male dark-eyed juncos deriving from a population that recently colonized a city (~35 years) and ceased migrating to that of conspecifics that live in sympatry with the urban population during winter and spring but migrate elsewhere to breed. We predicted that the earlier breeding sedentary urban birds would exhibit accelerated reproductive development in the spring along the hypothalamic-pituitary-gonadal (HPG) axis as compared to migrants. We found that free-living sedentary urban and migrant juncos differed at the level of the pituitary when measured as baseline luteinizing hormone (LH) levels, but not in increased LH when challenged with Gonadotropin-Releasing Hormone (GnRH). Among captives held in a common garden, and at the level of the gonad, we found that sedentary urban birds produced more testosterone in response to GnRH than migrants living in the same common environment, suggesting greater gonadal sensitivity in the derived urban population. Greater gonadal sensitivity could arise from greater upstream activation by LH or FSH or from reduced suppression of gonadal development by the adrenal axis. We compared abundance of gonadal transcripts for LH receptor (LHR), follicle stimulating hormone receptor (FSHR), glucocorticoid receptor (GR), and mineralocorticoid receptor (MR) in the common-garden, predicting either more abundant transcripts for LHR and FSHR or fewer transcripts for GR and MR in the earlier breeding sedentary urban breeders, as compared to the migrants. We found no difference in the expression of these genes. Together these data suggest that advanced timing of reproduction in a recently derived urban population is facilitated by earlier increase in upstream baseline activity of the HPG and earlier release from gonadal suppression by yet-to-be-discovered mechanisms. Evolutionarily, our results suggest that potential for gene flow between seasonally sympatric populations may be limited due to urban-induced advances in the timing of reproduction and resulting allochrony with ancestral forms.

California↗

USGS2008

Hydroacoustic measures of Mysis relicta abundance and distribution in Lake Ontario

Mysis relicta can be observed on echograms as a sound scattering layer when they migrate into the water column at night to feed on zooplankton. However, quantitative measures of mysid abundance with hydroacoustics requires knowledge of mysid target strength (TS), a method of removing fish echoes and contribution from noise, and an understanding of the effect of range on the ability of hydroacoustics to detect mysids (the detection limit). Comparisons of paired net data and acoustics data from July 7, 2005 yielded a mysid TS of -86.3 dB (9 mm animal) and a biomass TS of -58.4 dB (g dry wt)-1. With ambient noise levels (Sv of -125 dB at 1 m depth) and this TS, we can detect a mysid density of 1 m-3 at 60 m depth with a signal to noise ratio of 3 dB. We present a method to remove backscattering from both noise and fish and apply this method and the new TS data to whole lake acoustic data from Lake Ontario collected in July 25-31, 2005 with a 120 kHz echosounder as part of the annual standard fish survey in that lake. Mysis abundance was strongly depth dependent, with highest densities in areas with bottom depth > 100 m, and few mysids in areas with bottom depth < 50 m. With the data stratified in five bottom depth strata (> 100 m, 100-75 m, 75-50 m, 50-30 m, < 30 m), the whole-lake average mysid density was 118 m-2 (CV 21%) and the whole-lake average mysid biomass was 0.19 g dry wt m-2 (CV 22%) in July 2005. The CVs of these densities also account for uncertainty in the TS estimates. This is comparable to whole-lake density estimates using vertical net tows in November, 2005 (93 m-2, CV 16%). Copyright ?? 2008 AEHMS.

Conference Paper↗

USGS2016

Antigenic characterization of H3 subtypes of avian influenza A viruses from North America

Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

Avian Diseases↗

USGS2002

Variation in survivorship of a migratory songbird throughout its annual cycle

1. Demographic data from both breeding and non-breeding periods are needed to manage populations of migratory birds, many of which are declining in abundance and are of conservation concern. Although habitat associations, and to a lesser extent, reproductive biology, are known for many migratory species, few studies have measured survival rates of these birds at different parts of their annual cycle. 2. Cormack–Jolly–Seber models and Akaike’s information criterion model selection were used to investigate seasonal variation in survival of a Nearctic – Neotropical migrant songbird, the black-throated blue warbler, Dendroica caerulescens . Seasonal and annual survival were estimated from resightings of colour-ringed individuals on breeding grounds in New Hampshire, USA from 1986 to 2000 and on winter quarters in Jamaica, West Indies from 1986 to 1999. Warblers were studied each year during the May–August breeding period in New Hampshire and during the October–March overwinter period in Jamaica. 3. In New Hampshire, males had higher annual survival (0·51 ± 0·03) and recapture probabilities (0·93 ± 0·03) than did females (survival: 0·40 ± 0·04; recapture: 0·87 ± 0·06). In Jamaica, annual survival (0·43 ± 0·03) and recapture (0·95 ± 0·04) probabilities did not differ between sexes. Annual survival and recapture probabilities of young birds (i.e. yearlings in New Hampshire and hatch-year birds in Jamaica) did not differ from adults, indicating that from the time hatch-year individuals acquire territories on winter quarters in mid-October, they survive as well as adults within the same habitat. 4. Monthly survival probabilities during the summer (May–August) and winter (October–March) stationary periods were high: 1·0 for males in New Hampshire, and 0·99 ± 0·01 for males in Jamaica and for females in both locations. 5. These annual and seasonal survival estimates were used to calculate warbler survival for the migratory periods. Monthly survival probability during migration ranged from 0·77 to 0·81 ± 0·02. Thus, apparent mortality rates were at least 15 times higher during migration compared to that in the stationary periods, and more than 85% of apparent annual mortality of D. caerulescens occurred during migration. 6. Additional data from multiple species, especially measures of habitat-specific demography and dispersal, will improve our understanding of the relative impacts of the breeding, migratory, and winter periods on population dynamics of migratory birds and thus enhance future conservation efforts.

Journal of Animal Ecology↗

USGS2018

Infection by Nanophyetus salmincola and toxic contaminant exposure in out‐migrating steelhead from Puget Sound, Washington: Implications for early marine survival

Out‐migrating steelhead Oncorhynchus mykiss from four Puget Sound rivers and associated marine basins of Puget Sound in Washington State were examined for the parasite, Nanophyetus salmincola in 2014 to determine whether recent trends in reduced marine survival are associated with the presence of this pathogen. A subset of steelhead from three of these river–marine basin combinations was analyzed for the presence of persistent organic pollutants (POPs) to assess whether exposure to these contaminants is a contributing factor to their reduced marine survival. The prevalence and parasite load of N. salmincola were significantly higher in fish from central and southern Puget Sound than in fish from river systems in northern Puget Sound. The proportion of steelhead samples with concentrations of POPs higher than adverse effects thresholds (AETs) or concentrations known to cause adverse effects was also greater in fish from the central and southern regions of Puget Sound than in those from the northern region. Polybrominated diphenyl ether concentrations associated with increased disease susceptibility were observed in 10% and 40% of the steelhead sampled from central and southern Puget Sound regions, respectively, but in none of the fish sampled from the northern region. The AET for polychlorinated biphenyls was exceeded in steelhead collected from marine habitats: 25% of the samples from the marine basins in the central and southern regions of Puget Sound and 17% of samples from northern Puget Sound region. Both N. salmincola and POP levels suggest there are adverse health effects on out‐migrating steelhead from one southern and one central Puget Sound river that have lower early marine survival than those from a river system in northern Puget Sound.

Washington↗

USGS2011

Winter distribution of willow flycatcher subspecies

Documenting how different regions across a species' breeding and nonbreeding range are linked via migratory movements is the first step in understanding how events in one region can influence events in others and is critical to identifying conservation threats throughout a migratory animal's annual cycle. We combined two studies that evaluated migratory connectivity in the Willow Flycatcher ( Empidonax traillii ), one using mitochondrial DNA sequences from 172 flycatchers sampled throughout their winter range, and another which examined morphological characteristics of 68 museum specimens collected in the winter range. Our results indicate that the four subspecies occupy distinct but overlapping regions of the winter range. Connectivity between specific breeding and winter grounds appears to be moderate to strong, with distributions that suggest migration patterns of both the chain and leap-frog types connecting the breeding and nonbreeding grounds. The Pacific lowlands of Costa Rica appear to be a key winter location for the endangered Southwestern Willow Flycatcher ( E. t. extimus ), although other countries in Central America may also be important for the subspecies.

The Condor↗