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At least 1,351 records · Page 75Linked to original sources
USGS1998

Assessing relative abundance and reproductive success of shrubsteppe raptors

From 1991-1994, we quantified relative abundance and reproductive success of the Ferruginous Hawk (Buteo regalis), Northern Harrier (Circus cyaneus), Burrowing Owl (Speotytoc unicularia), and Short-eared Owl (Asio flammeus) on the shrubsteppe plateaus (benchlands) in and near the Snake River Birds of Prey National Conservation Area in southwestern Idaho. To assess relative abundance, we searched randomly selected plots using four sampling methods: point counts, line transects, and quadrats of two sizes. On a persampling-effort basis, transects were slightly more effective than point counts and quadrats for locating raptor nests (3.4 pairs detected/100 h of effort vs. 2.2-3.1 pairs). Random sampling using quadrats failed to detect a Short-eared Owl population increase from 1993 to 1994. To evaluate nesting success, we tried to determine reproductive outcome for all nesting attempts located during random, historical, and incidental nest searches. We compared nesting success estimates based on all nesting attempts, on attempts found during incubation, and the Mayfield model. Most pairs used to evaluate success were pairs found incidentally. Visits to historical nesting areas yielded the highest number of pairs per sampling effort (14.6/100 h), but reoccupancy rates for most species decreased through time. Estimates based on all attempts had the highest sample sizes but probably overestimated success for all species except the Ferruginous Hawk. Estimates of success based on nesting attempts found during incubation had the lowest sample sizes. All three methods yielded biased nesting snccess estimates for the Northern Harrier and Short-eared Owl. The estimate based on pairs found during incubation probably provided the least biased estimate for the Burrowing Owl. Assessments of nesting success were hindered by difficulties in confirming egg laying and nesting success for all species except the Ferruginous hawk.

Journal of Field Ornithology↗
USGS2001

Influence of military activities on raptor abundance and behavior

We investigated the influence of military training on the abundance and behavior of raptors at a military training area in the Snake River Birds of Prey National Conservation Area in Idaho during the breeding seasons of 1991a??1994. Raptor counts on military training ranges did not differ when we compared all training days to all non-training days. However, during one period of intensive military training in one breeding season, raptor counts were lower during training than on non-training days. During training, Northern Harriers (Circus cyaneus) did not alter their behavior on training days. In years when prey numbers were low, falcons, hawks, and eagles perched and flew at low levels less often and flew at higher altitudes more often during training than they did when training did not occur. We observed fewer prey capture attempts on ranges on days with training than on days without training. Specific types of military training activity affected counts of raptors on ranges. The lowest raptor counts were associated with firing of artillery, small arms, and main turret guns or machine guns on tanks. Raptor counts associated with tank preparation (i.e., assembling and loading ammunition), driving, laser training, and convoy traffic were similar to non-training periods.

The Condor↗
USGS2000

Turnover and dispersal of prairie falcons in southwestern Idaho

We studied Prairie Falcon (Falco mexicanus) breeding dispersal, natal dispersal, and turnover at nesting areas in the Snake River Birds of Prey National Conservation Area (NCA) from 1971- 95. Of 61 nesting areas where falcons identified one year were known to be present or absent the following year, 57% had a different falcon. This turnover rate was 2-3 times higher than that reported elsewhere for large falcons, and may have been related to high nesting densities in the NCA. Turnover at nesting areas was independent of nesting success in the previous year, but was significantly higher for females nesting on large cliffs. Mean distance between natal and breeding locations for 26 falcons banded as nestlings and later encountered as nesting adults was 8.9 km. Natal dispersal distances were similar for males and females, but more than twice as many males marked as nestlings were later encountered nesting in the NCA. Fourteen adult falcons found on different nesting areas in successive years moved an average of 1.5 km between nesting areas; males dispersed significantly farther than females. Natal and breeding dispersal distances in the NCA were lower than those reported for Prairie Falcons in other study areas. Only four falcons banded as nestlings were found outside NCA boundaries during the breeding period, and only one of these birds was known to be occupying a nesting area. We encountered no falcons banded outside the NCA occupying nesting areas in the NCA during this study.

Journal of Raptor Research↗
USGS1999

Effects of fire on golden eagle territory occupancy and reproductive success

We examined effects of fire on golden eagle (Aquila chrysaetos) territory occupancy and reproductive success in southwestern Idaho because wildfires since 1980 have resulted in large-scale losses of shrub habitat in the Snake River Plain. Success (percentage of pairs that raised young) at burned territories declined after major fires (P = 0.004). Pairs in burned areas that could expand into adjacent vacant territories were as successful as pairs in unburned territories and more successful than pairs in burned territories that could not expand. Success at extensively burned territories was lowest 4-6 years after burning but increased 4-5 years later. The incidence and extent of fires did not help predict territories that would have low occupancy and success rates in postburn years. The presence of a vacant neighboring territory and the amount of agriculture and proportion of shrubs within 3 km of the nesting centroid best predicted probability of territory occupancy. Nesting success during preburn years best predicted the probability of a territory being successful in postburn years. Burned territories with high success rates during preburn years continued to have high success rates during postburn years, and those with low success in preburn years continued to be less successful after burning. In areas where much shrub habitat has been lost to fire, management for golden eagles should include active fire suppression and rehabilitation of burned areas.

Journal of Wildlife Management↗
USGS2005

Monitoring temporal change in riparian vegetation of Great Basin National Park

Disturbance in riparian areas of semiarid ecosystems involves complex interactions of pulsed hydrologic flows, herbivory, fire, climatic effects, and anthropogenic influences. We resampled riparian vegetation within ten 10-m × 100-m plots that were initially sampled in 1992 in 4 watersheds of the Snake Range, east central Nevada. Our finding of significantly lower coverage of grasses, forbs, and shrubs within plots in 2001 compared with 1992 was not consistent with the management decision to remove livestock grazing from the watersheds in 1999. Change over time in cover of life-forms or bare ground was not predicted by scat counts within plots in 2001. Cover results were also not well explained by variability between the 2 sampling periods in either density of native herbivores or annual precipitation. In contrast, Engelmann spruce ( Picea engelmannii ) exhibited reduced abundance at all but the highest-elevation plot in which it occurred in 1992, and the magnitude of change in abundance was strongly predicted by plot elevation. Abundance of white fir ( Abies concolor ) individuals increased while aspen ( Populus tremuloides ) individuals decreased at 4 of 5 sites where they were sympatric, and changes in abundance in the 2 species were negatively correlated across those sites. Utility of monitoring data to detect change over time and contribute to adaptive management will vary with sample size, observer bias, use of repeatable or published methods, and precision of measurements, among other factors.

Nevada↗
USGS2006

Populations and habitat relationships of Piute ground squirrels in southwest Idaho

Piute ground squirrels (Spermophilus mollis idahoensis) are normally above ground from late January until late June or early July in the Snake River Birds of Prey National Conservation Area in southwestern Idaho. In 2002 they were rarely seen above ground after early May. Because of the ecological importance of ground squirrels for nesting raptors and other species, we sought to determine the reasons for their early disappearance. We sampled 12 sites from January 2003 through March 2003 to determine if a population crash had occurred in 2002. Tests indicated that Piute ground squirrels had not been exposed to plague within the past year. The presence of yearlings in the population indicated that squirrels reproduced in 2002 and that at least some yearlings survived the winter. Both yearling and adult squirrels appeared to be reproducing at or above normal rates in 2003. The most plausible explanation for the early disappearance of Piute ground squirrels in 2002 is that squirrels entered seasonal torpor early in response to a late spring drought. In addition, the breeding chronology of squirrels may have shifted during the past 2 decades in response to climate change and/or habitat alteration. Shrub habitats provide a more favorable and stable environment for squirrels than grass habitats. Squirrel abundance was higher on live-trapping grids with sagebrush than on grids dominated by grass, and squirrel masses were higher at sites dominated by shrubs and Sandberg bluegrass (Poa secunda). Densities in big sagebrush (Artemisia tridentata) were within the ranges reported for earlier years, but densities in grass were lower than previously reported. Low densities at grassland sites in 2003 support other findings that drought affects squirrels in altered grass communities more than those in native shrub habitats. Long-term shifts in ground squirrel breeding chronology may have implications for raptors that depend on them for food.

Western North American Naturalist↗
USGS2006

Effects of radio marking on prairie falcons: Attachment failures provide insights about survival

From 1999-2002, we attached satellite-received platform transmitter terminals (PTTs) to 40 adult female prairie falcons (Falco mexicanus) on their nesting grounds in the Snake River Birds of Prey National Conservation Area (NCA) in southwest Idaho. We used 3 variations of a backpack harness design that had been used previously on raptors. Each radiomarked falcon also received a color leg band with a unique alphanumeric code. We monitored survival of birds using radiotelemetry and searched for marked birds on their nesting grounds during breeding seasons after marking. Because 6 falcons removed their harnesses during the first year, we were able to compare survival rates of birds that shed PTTs with those that retained them. We describe a harness design that failed prematurely as well as designs that proved successful for long-term PTT attachment. We resighted 21 marked individuals on nesting areas 1-5 years after they were radiomarked and documented 13 mortalities of satellite-tracked falcons. We used a Cormack-Jolly-Seber model to estimate apparent survival probability based on band resighting and telemetry data. Platform transmitter terminals had no short-term effects on falcons or their nesting success during the nesting season they were marked, but birds that shed their transmitters increased their probability of survival. Estimated annual survival for birds that shed their transmitters was 87% compared to 49% for birds wearing transmitters. We discuss possible reasons for differences in apparent survival rates and offer recommendations for future marking of falcons.

Wildlife Society Bulletin↗
USGS1995

Agricultural drainwater effects on wildlife in central California

In California's San Joaquin Valley and in numerous other agricultural areas in the western U.S., irrigation wastewater may accumulate in confined shallow aquifers, eventually rising to levels that adversely affect crops. To sustain long-term agricultural productivity in these regions, systems for the drainage and disposal of this subsurface wastewater must be installed. 1,2 the drained water may contain an array of soluble chemicals that have been applied to the crops, as well as those that have been leached from native soils. Agricultural drainwater is frequently disposed of by discharging it to surface aquatic systems where these constituents may be directly toxic to aquatic organisms, or they may bioaccumulate through the aquatic food webs upon which birds and other wildlife feed. The focus of this chapter is research conducted since 1983 to assess the effects of wildlife exposure to subsurface agricultural drainwater in the San Joaquin Valley. Agricultural drainwater is discharged primarily to tributaries and wetlands of the San Joaquin River system or, especially in the southern San Joaquin Valley, to evaporation ponds. 3 Because of high nutrient content in the drainwater, evaporation ponds have high levels of biological productivity and provide an abundant food supply for aquatic birds. Aquatic birds (primarily waterfowl and shorebirds) have been the main focus of wildlife research at the evaporation ponds, and at managed wetlands (primarily hunting clubs) within the San Joaquin River system, but mammals, snakes, and frogs have also been studied. Findings of those studies are summarized in this chapter. Other studies have been conducted on fish and aquatic invertebrates in areas receiving agricultural drainwater, but in this review those findings are described only as they relate to dietary exposure of wildlife.

Book chapter↗
USGS2000

Herpetofauna of the Beni Biological Station Biosphere Reserve, Amazonian Bolivia: Additional information, and current knowledge in context

Previous collections in the Departamento del Beni in tropical Bolivia only hinted at high levels of herpetological biodiversity (Fugler 1986, 1988; de la Riva 1990a; Fugler and de la Riva 1990). Fieldwork (totaling 48 days) in July-August 1988 and September 1987 (dry seasons) and November-December 1990 (wet season) has resulted in collection and identification of 401 amphibian and reptilian specimens from the general area of the Beni Biological Station's (EBB) headquarters at El Porvenir. These collections represent 33 amphibian and 17 reptilian species in 29 genera (14 amphibian, 15 reptilian). The inventory of herpetofauna scientifically documented to occur in the Departamento del Beni is considered to have been increased by 6 amphibian and 10 reptilian species. Specimens that could not be definitively identified (reflecting taxonomic uncertainty and/or probably species new to science) include 3 amphibian species (anurans) and 2 reptilian species (snakes). The EBB harbors the richest savanna for anuran species known in South America.

Book chapter↗
USGS1998

Breeding biology of Acadian flycatchers in a bottomland hardwood forest

From 1993-1995, we located and monitored 601 Acadian Flycatcher (Empidonax virescens) nests in a large contiguous tract of bottomland hardwood forest on the White River National Wildlife Refuge, Arkansas. Annual reproductive success was significantly different among years; ranging from 10-25% (Mayfield estimate) over the three years of the study. There was no significant difference in nest success among study plots, with nesting success showing a trend of increasing late in the breeding season. Clutch size for non-parasitized nests averaged 2.9 ? 0.02 (SE) eggs with a mode of 3. Rates of Brown-headed Cowbird (Molothrus ater) parasitism were low (21%), accounting for 7% of all nest failures. However, parasitism by cowbirds resulted in a reduction of clutch size for nests initiated early (i.e., first nests and replacements) in the breeding season. Predation was the leading cause of nest failures, accounting for 75% of all failures. Snakes and avian predators were thought to be the leading cause of nest failures. Although additional factors must be investigated, preliminary results indicate that nest predation is a major influence on this population, despite the size of the forest tract.

The Wilson Bulletin↗
USGS2002

Invasive plant species: Inventory, mapping, and monitoring - A national strategy

America is under siege by invasive species of plants and animals, and by diseases. The current environmental, economic, and health-related costs of invasive species could exceed $138 billion per year-more than all other natural disasters combined. Notorious examples include West Nile virus, Dutch elm disease, chestnut blight, and purple loose- strife in the Northeast; kudzu, Brazilian peppertree, water hyacinth, nutria, and fire ants in the Southeast; zebra mussels, leafy spurge, and Asian long-horn beetles in the Midwest; salt cedar, Russian olive, and Africanized bees in the Southwest; yellow star thistle, European wild oats, oak wilt disease, Asian clams, and white pine blister rust in California; cheatgrass, various knapweeds, and thistles in the Great Basin; whirling disease of salmonids in the Northwest; hundreds of invasive species from microbes to mammals in Hawaii; and the brown tree snake in Guam. Thousands of species from other countries are introduced intentionally or accidentally into the United States each year. Based on past experience, 10-15 percent can be expected to establish free-living populations and about 1 percent can be expected to cause significant impacts to ecosystems, native species, economic productivity, and (or) human health.

Information and Technology Report↗
USGS2011

Boa constrictor (Boa constrictor): foraging behavior

Boa constrictor is often referred to as a sit-and-wait or ambush forager that chooses locations to maximize the likelihood of prey encounters (Greene 1983. In Janzen [ed.], Costa Rica Natural History, pp. 380-382. Univ. Chicago Press, Illinois). However, as more is learned about the natural history of snakes in general, the dichotomy between active versus ambush foraging is becoming blurred. Herein, we describe an instance of diurnal active foraging by a B. constrictor, illustrating that this species exhibits a range of foraging behaviors.

Herpetological Review↗
USGS2009

Mine spoil prairies expand critical habitat for endangered and threatened amphibian and reptile species

Coal extraction has been occurring in the Midwestern United States for over a century. Despite the pre-mining history of the landscape as woodlands, spent surface coalfields are often reclaimed to grasslands. We assessed amphibian and reptile species on a large tract of coal spoil prairie and found 13 species of amphibians (nine frog and four salamander species) and 19 species of reptiles (one lizard, five turtle, and 13 snake species). Two state-endangered and three state species of special concern were documented. The amphibian diversity at our study site was comparable to the diversity found at a large restored prairie situated 175 km north, within the historic prairie peninsula.

Diversity↗
USGS2011

Habits and Habitats of Fishes in the Upper Mississippi River

The Upper Mississippi River consists of 26 navigation pools that provide abundant habitat for a host of natural resources, such as fish, migratory waterfowl, non-game birds, deer, beaver, muskrats, snakes, reptiles, frogs, toads, salamanders, and many others. Of all the many different types of animals that depend on the river, fish are the most diverse with over 140 different species. The sport fishery is very diverse with at least 25 species commonly harvested. Fish species, such as walleyes, largemouth bass, bluegills, and crappies are favorites of sport anglers. Others such as common carp, buffalos, and channel catfish, are harvested by commercial anglers and end up on the tables of families all over the country. Still other fishes are important because they provide food for sport or commercial species. The fishery resources in these waters contribute millions of dollars to the economy annually. Overall, the estimate impact of anglers and other recreational users exceeds $1.2 billion on the Upper Mississippi River. The fisheries in the various reaches of the river of often are adversely affected by pollution, urbanization, non-native fishes, navigation, recreational boating, fishing, dredging, and siltation. However, state and federal agencies expend considerable effort and resources to manage fisheries and restore river habitats. This pamphlet was prepared to help you better understand what fishery resources exist, what the requirements of each pecies are, and how man-induced changes that are roposed or might occur could affect them.

Illinois;Iowa;Minnesota;Missouri;Wisconsin↗
USGS1985

Chloride flux out of Yellowstone National Park

Monitoring of the chloride concentration, electrical conductivity, and discharge was carried out for the four major rivers of Yellowstone National Park from September 1982 to January 1984. Chloride flux out of the Park was determined from the measured values of chloride concentration and discharge. The annual chloride flux from the Park was 5.86 ?? 1010 g. Of this amount 45% was from the Madison River drainage basin, 32% from the Yellowstone River basin, 12% from the Snake River basin, and 11% from the Falls River basin. Of the annual chloride flux from the Yellowstone River drainage basin 36% was attributed to the Yellowstone Lake drainage basin. The geothermal contribution to the chloride flux was determined by subtracting the chloride contribution from rock weathering and atmospheric precipitation and is 94% of the total chloride flux. Calculations of the geothermal chloride flux for each river are given and the implications of an additional chloride flux out of the western Park boundary discussed. An anomalous increase in chloride flux out of the Park was observed for several weeks prior to the Mt. Borah earthquake in Central Idaho on October 28, 1983, reaching a peak value shortly thereafter. It is suggested that the rise in flux was a precursor of the earthquake. The information in this paper provides baseline data against which future changes in the hydrothermal systems can be measured. It also provides measurements related to the thermal contributions from the different drainage basins of the Park. ?? 1985.

Journal of Volcanology and Geothermal Research↗
USGS1986

Tectonic and magmatic development of the Great Basin of western United States during the late Cenozoic time.

In the later Cainozoic, approx 18 m.y. ago, the first basin and range faulting developed in the central part of the Great Basin, this extensional tectonic system resulting from drag on the North American plate as the Pacific plate moved obliquely to the NW along the San Andreas fault. The northern boundary of the Great Basin at the Snake River plain and W across SE Oregon is the tectonic zone along which the E-W extending Basin and Range province has been moving for the past 18 m.y. In the Great Basin axis a narrow N-trending zone of basalt intruded the crust at the same time that basin and range faulting developed; this belt widens northwards as it approaches the N edge of the Great Basin and becomes diffuse and widespread in SE Oregon and SW Idaho, reaching enormous dimensions in the Columbia Plateau farther N. The basalt, which replaced andesitic igneous activity in the mid-Cainozoic, was produced by widespread partial melting in the upper mantle when the tectonic regime changed from a convergent- and subduction-related system to the extensional basin and range system. The locus of magma generated migration to the E and W margins of the Great Basin simultaneously and, as it migrated, it produced a series of eruptive centres along the N boundary of the Great Basin.-R.A.H.

Modern Geology↗
USGS1997

Soil development on a Pleistocene terrace sequence, Boise Valley, Idaho

Study of a sequence of terraces in the western Snake River Plain of Idaho reveals a record of at least seven terraces, the ages of which span the Pleistocene. In the Boise Valley, the youngest terraces are less than -14,500 yr and the oldest terraces are -1.7 Ma. Within this sequence, several relationships exist between soil morphology and terrace chronology. On terraces older than -14,500 yr, argillic horizon development generally increases with terrace age with maximum development occurring in soils of the oldest terraces. CaCO3- and SiO2-cemented duripans are found in soils on terraces that are late middle Pleistocene and older. By virtue of their physical and chemical properties, duripans are very resistant to erosion, and therefore provide stable records of CaCO3 and SiO2 accumulation throughout multiple cycles of loess deposition onto the terrace treads, pedogenesis, and partial erosion. Mean duripan thickness increases with age to a maximum of 0.66 m on the oldest terraces. Our results suggest that a geomorphic surface age of approximately 130,000 yr is required to form the initial plugged horizon that is characteristic of a duripan. CaCO3 and SiO2 accumulation is most rapid in duripans occupying geomorphic surfaces with ages ranging from 130,000 to 300,000 yr. After this, apparent accumulation rates decrease and little additional accumulation of these cementing agents occurs with time.

Northwest Science↗
USGS2000

Diet of first-feeding larval and young-of-the-year white sturgeon in the lower Columbia River

In some Snake and Columbia River reservoirs, adult white sturgeon (Acipenser transmontanus) are common but few juvenile fish are found, indicating a lack of spawning success or poor survival of larvae. In contrast, recruitment of young-of-the-year white sturgeon to juvenile and adult stages is successful in the unimpounded Columbia River downstream of Bonneville Dam. The availability and size of preferred prey during the period when white sturgeon larvae begin exogenous feeding could be an important determinant of year-class strength. To explore this issue, we examined the diet composition of 352 larval and young-of-the year white sturgeon collected from 1989 through 1991 in the lower Columbia River. Samples were collected downstream from Bonneville Dam and upstream from the dam in Bonneville and The Dalles Reservoirs. Fish that ranged in size from 15 to 290 mm in total length fed primarily on gammarid amphipods (Corophium spp.) during all months. This diet item became increasingly important to all sizes of white sturgeon examined as they grew. The length of Corophium spp. eaten by larval and young-of-the-year white sturgeon increased with increasing fish length (r2 = 45.6%, P < 0.0001). Copepods (Cyclopoida), Ceratopogonidae larvae, and Diptera pupae and larvae (primarily chironomids) were also consumed, especially at the onset of exogenous feeding. A small percentage of white sturgeon were found with empty stomachs during June (1.6% downstream from Bonneville Dam) and July (4.5% downstream and 2.6% in the reservoirs). Diets of larval and young-of-the year white sturgeon from both impounded and free-flowing sections of the Columbia River were similar and we found no evidence of larval starvation in the areas investigated, areas currently supporting healthy white sturgeon populations.

Northwest Science↗