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USGS2016

Recurrent hybridization and recent origin obscure phylogenetic relationships within the ‘white-headed’ gull (Larus sp.) complex

Species complexes that have undergone recent radiations are often characterized by extensive allele sharing due to recent ancestry and (or) introgressive hybridization. This can result in discordant evolutionary histories of genes and heterogeneous genomes, making delineating species limits difficult. Here we examine the phylogenetic relationships among a complex group of birds, the white-headed gulls (Aves: Laridae), which offer a unique window into the speciation process due to their recent evolutionary history and propensity to hybridize. Relationships were examined among 17 species (61 populations) using a multilocus approach, including mitochondrial and nuclear intron DNA sequences and microsatellite genotype information. Analyses of microsatellite and intron data resulted in some species-based groupings, although most species were not represented by a single cluster. Considerable allele and haplotype sharing among white-headed gull species was observed; no locus contained a species-specific clade. Despite this, our multilocus approach provided better resolution among some species than previous studies. Interestingly, most clades appear to correspond to geographic locality: our BEAST analysis recovered strong support for a northern European/Icelandic clade, a southern European/Russian clade, and a western North American/ canus clade, with weak evidence for a high latitude clade spanning North America and northwestern Europe. This geographical structuring is concordant with behavioral observations of pervasive hybridization in areas of secondary contact. The extent of allele and haplotype sharing indicates that ecological and sexual selection are likely not strong enough to complete reproductive isolation within several species in the white-headed gull complex. This suggests that just a few genes are driving the speciation process.

Molecular Phylogenetics and Evolution↗

USGS1986

The Breeding Bird Survey: Its first fifteen years, 1965-1979

The Breeding Bird Survey (BBS) is an ongoing cooperative program sponsored jointly by the U.S. Fish and Wildife Service and the Canadian Wildlife Service. Its main purpose is to estimate population trends of the many species of birds that nest in North America north of Mexico and that migrate across international boundaries. This survey provides information, both locally by ecological or political regions and on a continental scale, on (1) short-term population changes that can be correlated with specific weather incidents, (2) recovery periods following catastrophic declines, (3) normal year-to-year variations, (4) long-term population trends, and (5) invasions of exotics. The BBS also permits detailed computer mapping of relative abundance of each species, either year by year to show changes in distribution and relative abundance, or the average over a period of years. It provides base-line data with which more intensive local studies can be compared. For biogeographic studies it provides uniform sampling of bird populations by major physiographic regions across the continent. In conjunction with the Audubon Christmas Bird Count, it permits comparison of summer and winter distribution of species that winter in the United States. Most species of North American birds migrate across international boundaries, especially those shared with Canada, Mexico, and the Soviet Union. As part of our responsibility under treaties with these nations, the U.S. Fish and Wildlife Service has developed the BBS to monitor avian population changes so that any adverse trends can be detected early. This provides the opportunity to determine the reasons for any increase or decrease, to define geographic areas in which changes are greatest, to study correlations between avian population changes and land-use changes, and to make recommendations for controlling undesirable bird population trends. For example, the BBS can be used to detect and estimate the extent of losses resulting from widespread use of pesticides, and to reveal whether major population changes of a given species (e.g., Dickcissel) in certain States are related to a continental decline or are merely a result of population shifts within the breeding range. Effects of urban and suburban expansion are often reflected in the loss of forest interior birds. Population trends for 230 species as well as several avian genera and families are discussed and graphed in this report. For most of these species, regional and well as continental trends are shown. The three major regions discussed are the Eastern, Central, and Western, bounded by the Mississippi River and the eastern base of the Rocky Mountains. Additional graphs for certain States or physiographic regions are included for selected species of special interest. The following paragraphs summarize general trends in the major bird families. The native herons in general are maintaining their populations, whereas the exotic Cattle Egret continues its geographic spread and its steady increase. Waterfowl as a group are stable or increasing. Although most widespread species of hawks are on the increase, the rarer species show evidence of decline. Among the gallinaceous birds, the greatest change was a sharp drop in Northern Bobwhite as a result of the exceptionally cold winters of 1976-77 and 1977-78 in the Ohio Valley and the Middle Atlantic States. Killdeer populations, except for a minor decline during these two winters, showed strong increases except in the West. American Woodcock were poorly sampled by the BBS because they were relatively inactive during daylight. Common Snipe and the other common shorebirds that nest in the United States and southern Canada exhibited stable or increasing populations, especially in the Eastern and Central regions. Herring Gull counts varied dramatically and irregularly from year to year. Laughing Gulls increased along the Atlantic coast and Franklin's Gulls declined in the interior of the continen

Resource Publication↗

USGS2008

Yellow-billed Cuckoo Distribution, Abundance, and Habitat Use Along the Lower Colorado River and Its Tributaries, 2007 Annual Report

This 2007 annual report details the second season of a 2-year study documenting western yellow-billed cuckoo (Coccyzus americanus occidentalis) distribution, abundance, and habitat use throughout the Lower Colorado River Multi-Species Conservation Program boundary area. We conducted cuckoo surveys at 40 sites within 14 areas, between 11 June and 9 September 2007. The 169 surveys across all sites yielded 163 yellow-billed cuckoo detections. Cuckoos were detected at 25 of the 40 sites, primarily at the Bill Williams River National Wildlife Refuge (NWR) study area (n = 139 detections; 85 percent of all detections). Detections declined slightly through the cuckoo breeding season, with most detections occurring in the first and second survey periods (n = 92; 54 percent). We detected breeding activity only at the Bill Williams River NWR, where we confirmed 27 breeding events, including two nesting observations. However, the breeding status of most detected birds was unknown. We used playback broadcast recordings to survey for yellow-billed cuckoos. Compared to simple point counts or surveys, this method increases the number of detections of this secretive, elusive species. It has long been suspected that cuckoos have a fairly low response rate, and that the standard survey method of using broadcast recordings might fail to detect all birds present in an area. In 2007, we found that the majority (84 percent) of cuckoo detections were solicited through broadcast at all study sites. The number of solicited detections was highest during the first survey period and declined as the breeding season progressed, while the number of unsolicited detections (cuckoos heard calling before broadcast was initiated) remained fairly constant through the first, second, and third survey periods. The majority (66 percent) of cuckoo detections, solicited or unsolicited, were aural, 23 percent were both heard and seen, and 11 percent were visual detections only. We also found that 50 percent of all responses by cuckoos were evenly split between the first and second broadcasts at sites with >10 detections, while 45 percent of responses occurred after a single broadcast at the sites with <10 detections. We refined our collection of vegetation data in 2007 and found that across the entire study area the dominant tree species were tamarisk (Tamarix spp.), willow (Salix spp.), and cottonwood (Populus spp.). The smallest size class (<8 cm diameter at breast height) trees were the most common and were dominated by tamarisk, but cottonwood and willows were well represented in the larger size classes. Sites that were occupied by yellow-billed cuckoos generally had higher canopies, denser cover in the upper layers of the canopy, and sparse shrub layers compared to unoccupied sites that consistently had higher densities of woody species. As most occupied sites were within the Bill Williams River NWR and most unoccupied sites were at Grand Canyon National Park/Lake Mead National Recreation Area, vegetation characteristics at these study areas drove the cuckoo distribution patterns we observed in 2007. However, there was a range of habitat conditions in locations that were used by yellow-billed cuckoos across the entire lower Colorado River Multi-Species Conservation Program study area. We measured microclimate variables (temperature, relative humidity, soil moisture) at occupied and unoccupied sites, and found that, across the entire study area, occupied sites were consistently cooler during the day and more humid during the day and night compared to unoccupied sites, but that soil moisture did not differ between occupied and unoccupied sites. While most cuckoo detections occurred at Bill Williams River NWR, with generally cooler and more humid conditions, cuckoos were also detected at study areas that had hotter and dryer microclimate conditions. We did not find any relationship of canopy cover characteristics to temperature or soil moisture, suggesting

Open-File Report↗

USGS2002

Waterbird use of bayland wetlands in the San Francisco Bay estuary: Movements of long-billed dowitchers during the winter

The San Francisco Bay estuary is a migration and wintering area for more than 1.5 million waterbirds on the west coast of North America. Because the estuary is located in a metropolitan area, development and diking of baylands (the region between the edge of the bay and the historical high tide line) have greatly altered the wetland landscape. Recently, conservation interests have promoted restoration of diked baylands to tidal salt marshes for the benefit of endangered native species. However, effects of tidal marsh conversion on the existing community of waterbirds in the baylands are largely unknown, especially in muted tidal marshes with restricted inflows and in artificial salt evaporation ponds where high waterbird densities are found. The first radio-marking study of the Long-billed Dowitcher ( Limnodromus scolopaceus ) was conducted in November-December 2000 to examine their use of baylands. We captured 32 birds by rocket netting in a muted tidal marsh on the North Bay and radio-marked them with 1.2 g transmitters affixed with glue. Individuals were tracked for an average of 20.3 d (±8.5 SD) and obtained 217 high tide and 195 low tide locations. Movements between tides (x̄ = 1.29±1.48 SD km) and home range sizes (x̄ = 17.7±16.0 SD km 2 ) were highly variable. Long-billed Dowitchers preferred open habitats such as muted tidal marshes during the high tide, but the majority (78.5%) also remained in these wetlands during low tide rather than feeding at nearby mud flats. Their avoidance of mud flats contrasted sharply with Western Sandpipers ( Calidris mauri ) but was similar to Black-necked Stilts ( Himantopus mexicanus ). Seven Long-billed Dowitchers flew 110 km inland to Central Valley wetlands in mid-December, a regional movement documented earlier for Dunlin ( Calidris alpina ) wintering on the coast. However, unlike Dunlin, their movements were not in response to rainfall but may have been in response to a low pressure front or possibly predictable flooding of fields in the Central Valley. Although the estuary is a major wintering area supporting large numbers of waterbirds, some birds such as Long-billed Dowitchers move inland to freshwater wetlands in the Central Valley.

Waterbirds↗

USGS2012

Flow-adjusted trends in dissolved selenium load and concentration in the Gunnison and Colorado Rivers near Grand Junction, Colorado, water years 1986--2008

As a result of elevated selenium concentrations, many western Colorado rivers and streams are on the U.S. Environmental Protection Agency 2010 Colorado 303(d) list, including the main stem of the Colorado River from the Gunnison River confluence to the Utah border. Selenium is a trace metal that bioaccumulates in aquatic food chains and can cause reproductive failure, deformities, and other adverse impacts in birds and fish, including several threatened and endangered fish species. Salinity in the upper Colorado River has been the focus of source-control efforts for many years. Although salinity loads and concentrations have been previously characterized at the U.S. Geological Survey (USGS) streamflow-gaging stations at the Gunnison River near Grand Junction, Colo., and at the Colorado River near the Colorado-Utah State line, trends in selenium load and concentration at these two stations have not been studied. The USGS, in cooperation with the Bureau of Reclamation and the Colorado River Water Conservation District, evaluated dissolved selenium (herein referred to as "selenium") load and concentration trends at these two sites to inform decision makers on the status and trends of selenium. This report presents results of the evaluation of trends in selenium load and concentration for two USGS streamflow-gaging stations: the Gunnison River near Grand Junction, Colo. ("Gunnison River site"), USGS site 09152500, and the Colorado River near Colorado-Utah State line ("Colorado River site"), USGS site 09163500. Flow-adjusted selenium loads were estimated for the beginning water year (WY) of the study, 1986, and the ending WY of the study, 2008. The difference between flow-adjusted selenium loads for WY 1986 and WY 2008 was selected as the method of analysis because flow adjustment removes the natural variations in load caused by changes in mean-daily streamflow, emphasizing human-caused changes in selenium load and concentration. Overall changes in human-caused effects in selenium loads and concentrations during the period of study are of primary interest to the cooperators. Selenium loads for each of the 2 water years were calculated by using normalized mean-daily streamflow, measured selenium concentration, standard linear regression techniques, and data previously collected at the two study sites. Mean-daily streamflow was normalized for each site by averaging the daily streamflow for each day of the year over the 23-year period of record. Thus, for the beginning and ending water years, estimations could be made of loads that would have occurred without the effect of year-to-year streamflow variation. The loads thus calculated are illustrative of the change in loads between water years 1986 and 2008, and are not the actual loads that occurred in those 2 water years. The estimated 50th and 85th percentile selenium concentrations associated with the selenium loads were also calculated for WY 1986 and WY 2008 at each site. Time-trends in selenium concentration at the two sites were charted by using regression techniques for partial residuals for the entire study period (WY 1986 through WY 2008). Annual selenium load for the Gunnison River site was estimated to be 23,196 pounds for WY 1986 and 16,560 pounds for WY 2008, a 28.6 percent decrease. Lower and upper 95-percent confidence levels for WY 1986 annual load were 22,360 and 24,032 pounds. Lower and upper 95-percent confidence levels for WY 2008 annual load were 15,724 and 17,396 pounds. Estimated 50th percentile daily selenium concentrations decreased from 6.41 to 4.57 micrograms/liter from WY 1986 to WY 2008, whereas estimated 85th percentile daily selenium concentrations decreased from 7.21 to 5.13 micrograms/liter from WY 1986 to WY 2008. Annual selenium load for the Colorado River site was estimated to be 56,587 pounds for WY 1986 and 34,344 pounds for WY 2008, a 39.3 percent decrease. Lower and upper 95-percent confidence levels for WY 1986 annual load were 53,785 and 59,390 pounds. Lower and upper 95-percent confidence levels for WY 2008 annual load were 31,542 and 37,147 pounds. Estimated 50th percentile daily selenium concentrations decreased from 6.44 to 3.86 micrograms/liter from WY 1986 to WY 2008, whereas estimated 85th percentile daily selenium concentrations decreased from 7.94 to 4.72 micrograms/liter from WY 1986 to WY 2008.

Colorado↗

USGS1984

Heptachlor seed treatment contaminates hawks, owls, and eagles of Columbia Basin, Oregon

We evaluated organochlorine residues in 12 species of hawks. owls, and eagles from the Columbia Basin of Oregon between 1978 and 1981. Companion studies showed that heptachlor epoxide (HE) induced adult mortality and reduced productivity of the Canada Goose (Branta canadensis) and American Kestrel (Falco sparverius).ln this study, brain tissue from raptors found dead and sample eggs from 90 nests were analyzed for organochlorines. The primary concern was HE that entered raptor food chains through the ingestion of heptachlor-treated seed by their prey. HE residues were detected in eggs from 9 of 10 species and ranged as high as 4.75 ppm (wet wt), but no definite effects of HE on productivity were readily apparent from the limited series of nests. However, the hazard of heptachlor seed treatments to birds of prey was demonstrated by the occurrence of lethal residues of HE in brain tissue of 3 Golden Eagles (Aquila chrysaetos) and 1 Rough-legged Hawk (Buteo lagopus). Other organochlorine pesticides were present in the eggs and significant relationships were found between DDE and eggshell thickness for the Swainson's Hawk (Buteo swainsoni) and Western Screech-Owl (Otus kennicotti), although shell thinning (9.6% and 7.4%) was below the generally accepted range where reproductive problems have been known to occur.

Raptor Research↗

USGS1983

Yellow birds stand out in a crowd

Highly visible auxiliary markers, such as neck collars, nasal saddles, patagial tags, and leg streamers, are used regularly and effectively with banding in studying migration and distribution of large birds (e.g. waterfowl, birds of prey, wading birds). Simply stated, a large bird can accommodate a marker that is large enough to be seen readily by an observer but still small enough not to alter behavior or impair flight (see Marion and Shamis 1977 for review). Such is not true with smaller birds, and consequently information on their migration routes and distribution is usually poorer than for larger birds. The use of colored leg bands increases the frequency of detection of small birds that have been banded; however, a large percentage of such marked birds is usually still overlooked. Only by using highly visible techniques, such as plumage dyes and bleaches in conjunction with leg bands, can one obtain significant numbers of sightings of small birds. Here we present information from sightings of large numbers of marked Dunlins ( Calidris alpina ) and Western Sandpipers ( C. mauri ) that dramatically demonstrates this.

North American Bird Bander↗

USGS1986

Bird predation on cutworms (Lepidoptera: Noctuidae) in wheat fields and chlorpyrifos effects on brain cholinesterase activity

Horned larks, Eremophila alpestris (L.), and McCown's longspurs, Calcarius mccownii (Lawrence), were collected at intervals from two winter wheat fields in Montana after aerial application of chlorpyrifos to control cutworms. Both bird species had a high (95–100%) incidence of Lepidoptera, mostly pale western cutworms, Agrotis orthogonia Morrison, in their stomachs at 3 days postspray. Incidence of cutworms and other insects in stomachs of birds from sprayed fields was lower at 9 and 16 days postspray than in control birds, presumably due to insecticide-caused reduction of insects. Effects of birds on population dynamics of insect pests in wheat are unknown, but birds do contribute to cutworm mortality. Predation is one of the limiting factors to cutworm increase and can supplement insecticidal control. Brain cholinesterase activity in horned larks collected from the sprayed fields at 3 and 9 days postspray was significantly lower than in unexposed larks, but at 16 days the difference was not significant. Although nontarget birds clearly were exposed to chlorpyrifos and manifested a sublethal physiological response, toxic effects were lesssevere than those resulting from endrin application for cutworm control in wheat. More study is needed of larger chlorpyrifos-treated fields under a variety of conditions to fully assess effects on nontarget life.

Environmental Entomology↗

USGS2019

Eastern Pacific migration strategies of pink-footed shearwaters Ardenna creatopus: Implications for fisheries interactions and international conservation

The pink-footed shearwater Ardenna creatopus has a breeding range restricted to 3 central-Chilean islands and travels north in the eastern Pacific Ocean during the non-breeding period. Despite its Vulnerable IUCN status, the locations and relative importance of core non-breeding areas and migratory pathways of the species are not well understood. During 5 years between 2006 and 2015, we tracked the movements of 42 after-hatch-year pink-footed shearwaters in the non-breeding season using satellite tags. Tracked shearwaters exhibited 2 post-breeding-season migration strategies: 28% of individuals traveled 1600-2500 km north from their colonies to spend the entire non-breeding season off Peru, and 72% traveled 8000-11000 km north to waters off western North America (Baja California, Mexico, to southernmost Canada). Individuals that traveled to North America stopped in Peruvian waters on each leg of the migration, making this a migratory bottleneck. Core non-breeding-season areas included continental shelf and slope waters off Trujillo to Lima (Peru), central Baja California (Mexico), southern to central California (USA), and central Oregon (USA) to southern Vancouver Island (Canada). Of 12 national exclusive economic zones (EEZs) encountered north of their breeding range, birds primarily utilized the USA, Peru and Mexico, and to a lesser degree Chile, Canada, and Ecuador. Bycatch in fisheries was recently identified as a significant at-sea threat to pink-footed shearwaters, and we found evidence of pink-footed shearwater bycatch in 6 EEZs encountered by tracked birds, although quantification of bycatch magnitude is variable and not all fisheries have been studied.

Endangered Species Research↗

USGS1999

Sora rail studies on the Patuxent River, Maryland

The freshwater marshes of the tidal Patuxent River are well known for their annual fall concentration of migrant soras ( Porzana carolina ) and were formerly the most famous rail hunting grounds in the Chesapeake Bay region. Because of concern over the apparent long-term decline in number of soras and the decline in the quality of the Patuxent marshes, especially the loss of wild rice ( Zizania aquatica ), the Maryland National-Capital Park and Planning Commission (MNCPPC), co-steward of the Jug Bay National Estuarine Research Reserve, sponsored rail-related research beginning in 1987. Past efforts focused on developing efficient trapping techniques, age and sex criteria, and monitoring body mass dynamics. Noted progress was made in developing digital playback systems and trap improvements to enhance sora captures. These improvements increased capture success by over an order of magnitude and resulted in capture of 2,315 soras and 276 Virginia rails ( Rallus limicola ) in the 5 year period, 1993-97. Although these methods demonstrate the efficacy of banding large numbers of soras on migration and possibly winter concentration areas, captures at the Patuxent River site have been 70-90% hatching-year birds and recoveries and recaptures have been virtually nonexistent. With the present effort, this outcome precludes population parameter estimation using traditional capture-recapture or recovery model methodologies. In 1996, studies were initiated to employ radio telemetry methods to investigate length of stay, habitat use, survival, and migration characteristics of fall migrant soras. These studies are ongoing and will be continued through 1998 with a grant from the U.S. Fish and Wildlife Service's Webless Migratory Game Bird Research Program and support from the U.S. Geological Survey's Patuxent Wildlife Research Center. Supplemental funding has also been provided by MNCPPC, FWS Region 5, the Maryland Ornithological Society, Quail Unlimited, and Prince Georges Community College. During 1996-97 we developed a successful radio transmitter attachment technique to secure 1.8g radio transmitters over the synsacrum of migrant soras. We modified Rappole and Tipton's (1991) leg-loop attachment method by addition of a waist loop to prevent soras from slipping transmitters over their short tails. Thin gauge (0.6 mm) elastic thread proved ideal for attachment and allowed for girth expansion associated with fattening during stopover. Sixty instrumented soras have been monitored in two years of study from early September until early November. Only a single mortality was recorded and 41 (68%) were confIrmed and another 13 (total 90%) were believed to have migrated from the study area. Only a single bird slipped a radio transmitter. Most birds demonstrated a sedentary nature in the marsh throughout stopover. Average length of stay was 44 days in 1997 (n=29) with peak departure occurring 20-24 October. Departing migrants were detected using a receiver/data-logger monitoring system placed 4 miles down river from the study site. Thirty-six of 37 (97%) soras departed in a 2-hour window of time, beginning 1 hour after sunset. Departure was synchronized with cold fronts on clear, starlit nights. Twenty-five soras were monitored on migration from 8 km to as far away as 770 km. Findings indicate migration flight speeds of 40 to 50 mph and a direct southward orientation from the study site at least until contact with the Atlantic Ocean west of Cape Lookout, North Carolina. We also attempted to monitor passage of migrant soras radio tagged at Iroquois National Wildlife Refuge in western New York by biologist Soch Lor. None were recorded passing a monitoring unit at Haldeman Island in the middle of the Susquehanna River 10 miles north of Harrisburg, Pennsylvania. This further corroborates our findings that when migrating overland, soras move in a direct southward orientation and are not following land features such as major rivers

Book chapter↗

USGS1974

The literature of the California black rail

Few birds have remained so little known as the California black rail ( Laterallus jamaicensis coturniculus ). Although first collected in 1859 or before and reported in 1874 (Ridgway 1874), its life history, distribution, and status have remained so obscure that even a sight record of the bird is deemed worthy of a report in some ornithological publications. Because degradation and loss of freshwater and saltwater marshlands in California may be detrimentally affecting the black rail, both the U.S. Bureau of Sport Fisheries and Wildlife (1973) and the California Department of Fish and Game (1972) have classified it as rare and worthy of further study. The 84 papers and notes both summarized in this report and included in its bibliography include essentially all that is currently known about the California black rail. Only 11 of these papers consider the life history of this rail in any detail. The rest are distribution notes and some of the more important papers on the closely related eastern black rail ( L. j. jamaicensis ). The latter are included for comparative purposes, or because they may lend clues to currently unknown facets of the life history of the western race.

Special Scientific Report - Wildlife↗

USGS2015

Habitat manipulation influences northern bobwhite resource selection on a reclaimed surface mine

More than 600,000 ha of mine land have been reclaimed in the eastern United States, providing large contiguous tracts of early successional vegetation that can be managed for northern bobwhite ( Colinus virginianus ). However, habitat quality on reclaimed mine land can be limited by extensive coverage of non-native invasive species, which are commonly planted during reclamation. We used discrete-choice analysis to investigate bobwhite resource selection throughout the year on Peabody Wildlife Management Area, a 3,330-ha reclaimed surface mine in western Kentucky. We used a treatment-control design to study resource selection at 2 spatial scales to identify important aspects of mine land vegetation and whether resource selection differed between areas with habitat management (i.e., burning, disking, herbicide; treatment) and unmanaged units (control). Our objectives were to estimate bobwhite resource selection on reclaimed mine land and to estimate the influence of habitat management practices on resource selection. We used locations from 283 individuals during the breeding season (1 Apr–30 Sep) and 136 coveys during the non-breeding season (1 Oct–Mar 31) from August 2009 to March 2014. Individuals were located closer to shrub cover than would be expected at random throughout the year. During the breeding season, individuals on treatment units used areas with smaller contagion index values (i.e., greater interspersion) compared with individuals on control units. During the non-breeding season, birds selected areas with greater shrub-open edge density compared with random. At the microhabitat scale, individuals selected areas with increased visual obstruction >1 m aboveground. During the breeding season, birds were closer to disked areas (linear and non-linear) than would be expected at random. Individuals selected non-linear disked areas during winter but did not select linear disked areas (firebreaks) because they were planted to winter wheat each fall and lacked cover during the non-breeding season. Individuals also selected areas treated with herbicide to control sericea lespedeza ( Lespedeza cuneata ) throughout the year. During the breeding season, bobwhites avoided areas burned during the previous dormant season. Habitat quality of reclaimed mine lands may be limited by a lack of shrub cover and extensive coverage of non-native herbaceous vegetation. Managers aiming to increase bobwhite abundance should focus on increasing interspersion of shrub cover, with no area >100 m from shrub cover. We suggest disking and herbicide application to control invasive species and improve the structure and composition of vegetation for bobwhites.

Kentucky↗

USGS2000

Migration strategies and wintering areas of North American ospreys as revealed by satellite telemetry

Since 1995 we have trapped and tagged 110 Ospreys ( Pandion haliaetus ) from 12 study sites in 8 states (Fig. 1). This total includes 71 females, 32 males and 7 juveniles. Our study areas encompass the major Osprey population concentrations found in the United States including the Western States, the Great Lakes region and the Eastern Seaboard. Tagging of nesting pairs along with three complete family groups revealed that departure times from nesting areas varied by gender; with females leaving before the juveniles and the males departing last. Neither nesting pairs, nor families, migrated or wintered together (Fig. 2). Departure dates from the breeding areas ranged from 12 July to 1 October. Migration routes differed between populations but not gender (Fig. 3). Western Ospreys migrated through California and to a lesser degree other western states and then into Mexico. Minnesota Ospreys migrated along three routes; 1) through the central U.S. and then along the east coast of Mexico, 2) along the Mississippi River then across the Gulf of Mexico, or 3) through the Southeastern U.S., then across the Caribbean. East Coast birds migrated along the Eastern Seaboard of the U.S. through Florida and across the Caribbean.

Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mi↗

USGS1991

Accumulation of trace elements and organochlorines by surf scoters wintering in the Pacific northwest

Selenium, cadmium, mercury, copper, manganese, zinc, aluminum, lead, PCBs and DDE were accumulated by segments of the surf scoter (Melanitta perspicillata) population that winters in the Pacific Northwest, but whether the uptake occurred on breeding and/or wintering grounds was uncertain for some contaminants. Surf scoters collected in Puget Sound and San Francisco Bay (in another study) during the same period (January 1985) contained similar concentrations of cadmium, but Alsea Bay scoters contained more. Cadmium was inversely related to both liver and body weights of Northwest scoters in January; similar weight losses were reported in experimental laboratory studies. Northwest and north San Francisco Bay scoters contained similar mercury concentrations, but those in south San Francisco Bay contained higher concentrations. San Francisco Bay scoters contained higher arsenic and selenium concentrations than those in the Northwest; however, the 43.4 ppm (geometric mean, dry wt) selenium in livers at Commencement Bay in January was above levels associated with the reproductive problems in aquatic birds at Kesterson National Wildlife Refuge. Even higher concentrations of some elements may be found in surf scoters in March, because a later collection (March) at San Francisco Bay yielded higher concentrations than found there in January. Trace element concentrations in birds at a given wintering location are variable among species and may be influenced by diet, breeding grounds, and physiology (e.g., at Commencement Bay surf scoters with a sediment-associated diet contained 50X more cadmium in their kidneys than did fish-eating western grebes [Aechmophorus occidentalis]). The numerous wildlife species that live on estuaries require further attention.

Northwestern Naturalist↗

USGS2003

Escherichia coli and enterococci at beaches in the Grand Traverse Bay, Lake Michigan: Sources, characteristics, and environmental pathways

This study quantified Escherichia coli(EC) and enterococci (ENT) in beach waters and dominant source materials, correlated these with ambient conditions, and determined selected EC genotypes and ENT phenotypes. Bathing-water ENT criteria were exceeded more frequently than EC criteria, providing conflicting interpretations of water quality. Dominant sources of EC and ENT were bird feces (108/d/bird), storm drains (107/d), and river water (1011/d); beach sands, shallow groundwater and detritus were additional sources. Beach-water EC genotypes and ENT phenotypes formed clusters with those from all source types, reflecting diffuse inputs. Some ENT isolates had phenotypes similar to those of human pathogens and/or exhibited high-level resistance to human-use antibiotics. EC and ENT concentrations were influenced by collection time and wind direction. There was a 48-72-h lag between rainfall and elevated EC concentrations at three southern shoreline beaches, but no such lag at western and eastern shoreline beaches, reflecting the influence of beach orientation with respect to cyclic (3-5 d) summer weather patterns. In addition to local contamination sources and processes, conceptual or predictive models of Great Lakes beach water quality should consider regional weather patterns, lake hydrodynamics, and the influence of monitoring method variables (time of day, frequency).

Grand Traverse Bay↗

USGS2016

Survival and habitat use of fledgling Golden-winged Warblers in the western Great Lakes region

Postfledging habitat use and fledgling survival remain unstudied for most songbirds, but this period is critical for understanding breeding habitat associations and full-season productivity. We used radiotelemetry to study movements, cover-type selection, and survival of fledgling Golden-winged Warblers ( Vermivora chrysoptera ) during the dependent postfledging period in managed forest landscapes of the western Great Lakes region. We used logistic exposure models to determine the relative importance of various habitat characteristics for explaining fledgling survival. In addition, we used compositional analysis, corrected for age-specific fledgling movement capabilities, to test for resource selection, as use versus availability, among cover types. We estimated that 48% of fledglings were depredated before independence from adult care at 25 days after fledging. Fledgling survival was lowest immediately after fledging, and 86% of predation occurred in the first 8 days following fledging. Distance from the nest to forest-shrubland edge was the strongest predictor of young fledgling survival, as survival decreased with nest distance into shrubland cover types and increased with nest distance into forest cover types. Fledglings from nests in shrubland cover types moved toward the nearest forest-shrubland edge, whereas fledglings from nests in forest cover types did not move toward edge. Fledglings selected mature forest and sapling-dominated clear-cuts over all other cover types during the early postfledging period, and fledgling survival in mature forest and sapling-dominated clearcuts was greater than in shrub-dominated clearcuts or wetland shrublands. Fledglings that were 9–25 days postfledging experienced high survival (daily survival >0.99) that was independent of any habitat variables we measured, and birds selected mature forest and shrub-dominated clear-cuts over all other cover types during that period. We conclude that sapling-dominated clear-cuts or mature forest with dense understory and shrub layers, cover types traditionally not associated with breeding, are important for fledgling survival, and therefore full-seasonal productivity in Golden-winged Warblers

Studies in Avian Biology↗

USGS2012

Variation in migratory behavior influences regional genetic diversity and structure among American kestrel populations (Falco sparverius) in North America

Birds employ numerous strategies to cope with seasonal fluctuations in high-quality habitat availability. Long distance migration is a common tactic; however, partial migration is especially common among broadly distributed species. Under partial migration systems, a portion of a species migrates, whereas the remainder inhabits breeding grounds year round. In this study, we identified effects of migratory behavior variation on genetic structure and diversity of American Kestrels (Falco sparverius), a widespread partial migrant in North America. American Kestrels generally migrate; however, a resident group inhabits the southeastern United States year round. The southeastern group is designated as a separate subspecies (F. s. paulus) from the migratory group (F. s. sparverius). Using mitochondrial DNA and microsatellites from 183 and 211 individuals, respectively, we illustrate that genetic structure is stronger among nonmigratory populations, with differentiation measures ranging from 0.060 to 0.189 depending on genetic marker and analysis approach. In contrast, measures from western North American populations ranged from 0 to 0.032. These findings suggest that seasonal migratory behavior is also associated with natal and breeding dispersal tendencies. We likewise detected significantly lower genetic diversity within nonmigratory populations, reflecting the greater influence of genetic drift in small populations. We identified the signal of population expansion among nonmigratory populations, consistent with the recent establishment of higher latitude breeding locations following Pleistocene glacial retreat. Differentiation of F. s. paulus and F. s. sparverius reflected subtle differences in allele frequencies. Because migratory behavior can evolve quickly, our analyses suggest recent origins of migratory American Kestrel populations in North America.

Journal of Heredity↗

USGS2014

Spring migration ecology of the mid-continent sandhill crane population with an emphasis on use of the Central Platte River Valley, Nebraska

We conducted a 10-year study (1998–2007) of the Mid-Continent Population (MCP) of sandhill cranes (Grus canadensis) to identify spring-migration corridors, locations of major stopovers, and migration chronology by crane breeding affiliation (western Alaska–Siberia [WA–S], northern Canada–Nunavut [NC–N], west-central Canada–Alaska [WC–A], and east-central Canada–Minnesota [EC–M]). In the Central Platte River Valley (CPRV) of Nebraska, we evaluated factors influencing staging chronology, food habits, fat storage, and habitat use of sandhill cranes. We compared our findings to results from the Platte River Ecology Study conducted during 1978–1980. We determined spring migration corridors used by the breeding affiliations (designated subpopulations for management purposes) by monitoring 169 cranes marked with platform transmitter terminals (PTTs). We also marked and monitored 456 cranes in the CPRV with very high frequency (VHF) transmitters to evaluate length and pattern of stay, habitat use, and movements. An estimated 42% and 58% of cranes staging in the CPRV were greater sandhill cranes (G. c. tabida) and lesser sandhill cranes (G. c. canadensis), and they stayed for an average of 20 and 25 days (2000–2007), respectively. Cranes from the WA–S, NC–N, WC–A, and EC–M affiliations spent an average of 72, 77, 52, and 53 days, respectively, in spring migration of which 28, 23, 24, and 18 days occurred in the CPRV. The majority of the WA–S subpopulation settled in the CPRV apparently because of inadequate habitat to support more birds upstream, although WA–S cranes accounted for >90% of birds staging in the North Platte River Valley. Crane staging duration in the CPRV was negatively correlated with arrival dates; 92% of cranes stayed >7 days. A program of annual mechanical removal of mature stands of woody growth and seedlings that began in the early 1980s primarily in the main channel of the Platte River has allowed distribution of crane roosts to remain relatively stable over the past 2 decades. Most cranes returned to nocturnal roost sites used in previous years. Corn residues dominated the diet of sandhill cranes in the CPRV, as in the 1970s, despite a marked decline in standing crop of corn residues. Only 14% (10 of 74) of PTT-marked migrant cranes stayed at stopovers for ≥5 days before arriving in the CPRV, which limited the contribution of sites south of the CPRV for fat accumulation needed for migration and reproduction. Body masses of cranes (after adjusting for body size [an index of fat]) at arrival in the CPRV varied widely among years (1998–2006), indicating the importance of maintaining productive habitats on the wintering grounds to condition cranes for migration and reproduction. Average rates of fat gain by adult females while in the CPRV remained similar from 1978–1979 to 1998–1999 but declined among males. Distances cranes flew to feeding grounds in the CPRV increased as the percentage of cropland planted to soybeans increased and as density of cranes on nocturnal roosts increased. These results suggest that as habitats of limited or no value to cranes increase on the landscape, more flight time and higher maintenance costs may reduce fat storage. An estimated 40% of diurnal use occurred north of Interstate 80 (I-80) where ≤5% of lands dedicated to crane conservation are located. Seventy-four and 40% of PTT-marked EC–M and WC–A cranes had spring migrations that included staging in eastern South Dakota for an average of 11 and 10 days, respectively. Cranes of the NC–N, WA–S, and WC–A subpopulations staged an average of 25, 17, and 12 days in central and western Saskatchewan/eastern Alberta. Females in these affiliations increased their fat reserves after leaving Nebraska by an estimated 450, 451, and 452 g, respectively, underscoring the key role of these staging areas in preparing the 3 subpopulations for reproduction. After departing Nebraska, MCP cranes roosted primarily in basin wetlands. Most of these wetlands are in private ownership and lack adequate protection, emphasizing the need for effective laws and policies to ensure their long-term protection. The continued success of the current management goal of maintaining the MCP at approximately its current size and providing diverse recreational opportunities over a wide area of midcontinent and western North America is predicated on the ability of MCP cranes to continue to store large fat reserves in the CPRV in advance of breeding. For the CPRV to remain a key fat storage site, active channel maintenance (e.g., clearing of woody vegetation) likely will need to continue, along with establishing minimum stream flows. These actions would help ensure nocturnal roosting habitat remains sufficiently dispersed to provide cranes with daily intake of high-energy food adequate for major fat storage and limit risk of high mortality from storms and disease. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Nebraska↗