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At least 1,315 records · Page 73Linked to original sources
USGS1992

Effects of aerial applications of esfenvalerate on small mammals and birds in Douglas-fir seed orchards

Although no adverse effects were documented, this study did not provide data sufficient to adequately test for effects of aerial spraying of esfenvalerate on small mammal populations or nesting of birds in Douglas-fir seed orchards. Small mammal trapping data were too sparse to provide statistical testing with reasonable power. Residues of the R and S forms of fenvalerate were low with maxima of 0.56 and 1.72 ?g/g, respectively in pelage of a deer mouse. No diagnostic residue data are available to interpret our results.

Report↗
USGS1996

Atlas of the Breeding Birds of Maryland and the District of Columbia

This was the result of a 5-year cooperative study with the Maryland Ornithological Society and the Maryland Department of Natural Resources. Each of Maryland's 1,256 5-km (25 sq km) blocks was surveyed for breeding birds using the standard categories of Possible, Probable, and Confirmed breeding. Special features include: (1) coverage of all blocks instead of a random sample; (2) one-third of the state (including the most rapidly changing counties) was covered in quarterblocks (2.5 km on each side) to facilitate detecting future changes; (3) quantitative sampling (miniroutes) was completed in more than half the blocks; (4) a 2 percent statewide random sample of blocks was searched for about 30 hours each by Patuxent professionals to evaluate efficiency of coverage by the volunteers; (5) besides species maps for 1983-87, the atlas also includes distribution maps from the 1950s; (6) life history data are based largely on unpublished Maryland information.

Book↗
USGS2002

Exposure of free-flying birds to anticholinesterase insecticides in two conventionally managed fruit orchards

Conventionally managed orchards receive extensive applications of anticholinesterase (anti-ChE) insecticides throughout the growing season. Because many avian species make use of these environments for nesting and foraging, they may receive substantial exposure to anti-ChEs. The model used to assess avian risk in these environments is highly simplified, and indicator species used in risk studies may misrepresent the risk of the species in the field. A better understanding of avian risk is needed, and should begin with a closer examination o# their exposure in these environments. Exposure of free-flying birds was examined in two conventional orchards during the nesting seasons of 1999 and 2000. Our goal was to demonstrate the influences of species and chemical differences on the exposure we observed. Plasma ChE activity and ChE reactivation were used to identify exposure in multiple species following anti-ChE applications (applied singly and in mixtures). Chipping sparrows (Spizella passerina), American goldfinches (Carduelis tristis), and American robins (Turdus migratorius) demonstrated significant ChE activity depression in 1999 (p 0.005), and only chipping sparrows demonstrated significant depression in 2000 (p = 0.0002). These three species demonstrated the highest proportion of exposed individuals among all species examined in both years. Because many chemicals were simultaneously present in each orchard, chemical influences on the exposure we observed could not be discerned. This work does demonstrate, however, that avian species differ significantly in their exposure, and that chipping sparrows demonstrated the greatest exposure among the species analyzed. These results underscore the need for multiple species studies and for choosing indicator species on a biologically relevant basis.

Book↗
USGS1985

Recent changes in the ranges of North American birds

The North American Breeding Bird Survey has provided an annual index of population change since 1966. About 2400 randomly distributed roadside routes of 50 three-minute stops each provide the basic data for computer analysis. One of the reports produced shows the percentage of routes on which each species is encountered in each state and each Canadian province. This percentage is used to show expansion and contraction of breeding range and also important changes in frequency of encounter within various portions of the range of each species. Most of the recent changes in range fall in one of these 7 categories: (1) introduced species; (2) species given special protection; (3) species benefiting from artificial feeding in winter; (4) species taking advantage of shelterbelts; (5) species nesting on large highway bridges and dams; (6) species that feed on grain lost during mechanical harvesting: and (7) species losing habitat as a result of urban expansion. Examples of each category are supported by changes in the rate of encounter.

Book chapter↗
USGS1970

DDE and DDD residues correlated with mortality of experimental birds

Nearly everywhere in nature are found DDE and DDD, which are metabolites of DDT, and they often become concentrated through food chains. DDD is also a commercial insecticide. large amounts of both are frequently found in birds, but the significance of these amounts has puzzled many owrkers. Studies at Clear Lake, California 1 gave some data on DDD danger levels, but less is known of DDE, the member of the DDT group that is most frequent and most abundant in nature. Although DDE is toxic, relatively alrge residues are found in apparently healthy animals. As one step in untanglig the problem, it seemed important to determine the residue levels that indicate danger to life. earlier work with DDR and dieldrin has shown the value of this approach. 2-5, 1 2

Conference Paper↗
USGS1980

Techniques and results of nongame bird monitoring in North America

Long-term bird population trends based on accumulated ratios (proportional change) sometimes give a very misleading view of population change. Alternate methods of representing population change, based on the weighted means for the individual years, avoid the dangers of using ratios. Some advantages and disadvantages of various weighting techniques are discussed.

Book chapter↗
USGS1981

Reappraisal of the Winter Bird-Population Study technique

Standardized morning and afternoon counts were conducted in two deciduous forest plots during seven winters. Morning counts yielded more species than afternoon counts, as well as higher counts of most species. A minimum of eight visits is recommended. Six visits yielded 2% to 5% fewer species, depending on the size and bird population of the study plot. Cumulative means for individual species varied erratically for most species when the number of visits was less than seven.

Book chapter↗
USGS1981

Effect of time of day on bird activity

Breeding season activity, based on detections recorded on more than a million 3. minute Breeding Bird Survey stops, reaches a peak for most species during the hour centered at sunrise or in the following hour. Activity of most species then declines gradually as the morning progresses. When large samples are considered, activity patterns for a given species are quite constant from year to year; but each species has its own characteristic pattern and there is much similarity among members of the same genus. Activity reaches a low point in midday, and may almost cease in some habitats (e. g. deserts); but in deciduous forests, activity of many species continues at a reduced rate. By reducing walking rate or lengthening listening periods, productive censusing of many species could be extended into midday. Winter activity is even more strongly oriented toward the early morning.

Book chapter↗
USGS1985

Maximum likelihood methods for investigating reporting rates of rings on hunter-shot birds

It is well known that hunters do not report 100% of the rings that they find on shot birds. Reward studies can be used to estimate what this reporting rate is, by comparison of recoveries of rings offering a monetary reward, to ordinary rings. A reward study of American Black Ducks (Anas rubripes) is used to illustrate the design, and to motivate the development of statistical models for estimation and for testing hypotheses of temporal and geographic variation in reporting rates. The method involves indexing the data (recoveries) and parameters (reporting, harvest, and solicitation rates) by geographic and temporal strata. Estimates are obtained under unconstrained (e.g., allowing temporal variability in reporting rates) and constrained (e.g., constant reporting rates) models, and hypotheses are tested by likelihood ratio. A FORTRAN program, available from the author, is used to perform the computations.

Book chapter↗
USGS1987

Relationships between nesting populations of wading birds and habitat features along the Atlantic Coast

Using previously published atlas data for 122 mixed-species wading bird colonies on islands along the Atlantic coast (Maine to Florida, 1976-77), we examined relationships between population sizes of 11 species of egrets, herons, ibises, and wood storks (Mycteria americana) and nine habitat variables. On nautical charts, we measured four island characteristics (area, length, width, shape), three isolation factors (distances to nearest island, mainland, and a water barrier),, and two variables related to potential feeding habitat within 5 km of the center of the colony (wetland area and land-water interface, i.e., the linear distance between the marsh/upland and all water bodies within the same 5-km radius). One univariable and five multivariable .procedures were used to determine which habitat features were best related to population size .(all species combined). Multicollinearity problems among the variables limited interpretation for most procedures. Both univariable and the multivariable procedures indicated that land-water interface was the most important of the nine variables, but for all models, less than 10% of the total variance was explained (rz is less than 0.10). The size of the colony was not related to the amount of wetland area (within 5-km).per se. Colony data showed better 'structure' when examined on the basis of geographic and disturbance gradients. Population sizes of colonies near man-altered habitats were compared with those surrounded by relatively natural habitats in three geographic zones: north, middle, and south. Significant differences were found in colony size among the three zones (south largest) and between disturbance types. Surprisingly, in all three zones, colonies near man-altered areas were larger on average than those near more natural habitats in this region. A possible reason for this difference is suggested.

Book chapter↗
USGS1995

Mapping of bird distributions from point count surveys

Maps generated from bird survey data are used for a variety of scientific purposes, but little is known about their bias and precision. We review methods for preparing maps from point count data and appropriate sampling methods for maps based on point counts. Maps based on point counts can be affected by bias associated with incomplete counts, primarily due to changes in proportion counted as a function of observer or habitat differences. Large-scale surveys also generally suffer from regional and temporal variation in sampling intensity. A simulated surface is used to demonstrate sampling principles for maps.

Book chapter↗
USGS1990

Northern bobwhite, gray partridge, and ring-necked pheasant population trends (1966-1988) from the North American Breeding Bird Survey

We use North American Breeding Bird Survey data to estimate population trends for 1966-1988 for northern bobwhite (Colinus virginianus), ring-necked pheasant (Phasianus colchicus), and gray partridge (Perdix perdix). Bobwhite populations have undergone widespread declines, pheasant have undergone major declines in eastern North America with mixed trends elsewhere, gray partridge have undergone primarily population increases. We present suggestions for further uses of these data.

Book chapter↗
USGS1995

Population trends of the loggerhead shrike from the North American Breeding Bird Survey

North American Breeding Bird Survey data indicated a general decline in Loggerhead Shrike (Lanius ludovicianus) populations during 1966-1993. At the continental level, shrikes declined at an average rate of 2.9% per year. Average rates of regional declines varied from 2.5-3.4% annually. These declines were prevalent in most states, provinces, and physiographic strata. Only the Edwards Plateau, High Plains, and Great Plains Roughlands strata, and Colorado, Louisiana, Montana, and South Dakota apparently have stable breeding populations. Severe winter weather during 1976-1979 may have contributed to this decline in the eastern half of the continent, combining with other factors during the winter and breeding seasons that have been implicated in the rangewide decline of this species.

Book chapter↗
USGS1995

Estimating bird species richness from capture and count data

We used capture-recapture methods to estimate bird species richness from mist-net and point-count data from a study area in Campeche, Mexico. We estimated species richness separately for each survey technique for two habitats, forest and pasture, in six sampling periods. We then estimated richness based on species' detections by either technique, and estimated the proportion of species detected by each technique that are not part of the population sampled by the other technique. No consistent differences existed between richness estimates from count data and from capture data in the two habitats. In some sampling periods, over 50% of the richness estimate from one survey technique may be species that are not sampled by the other technique, suggesting that one technique may not be adequate to estimate total species richness and that comparing estimates from areas sampled by different techniques may not be valid.

Book chapter↗
USGS1993

Overview of national bird population monitoring programs and databases

A number of programs have been set up to monitor populations of nongame migratory birds. We review these programs and their purposes and provide information on obtaining data or results from these programs. In addition, we review recommendations for improving these programs.

Book chapter↗
USGS1993

Sampling bird communities in bottomland hardwood forests of the Mississippi Alluvial Valley: Number of points visited versus number of visits to a point

Within each of 4 forest stands on Delta Experimental Forest (DEF), 25 points were visited 5 to 7 times from 8 May to 21 May 1991, and 6 times from 30 May to 12 June 1992. During each visit to a point, all birds detected, visuallyor aurally, at any distance were recorded during a 4-minute interval. Using these data, our objectives were to recommend the number of point counts and the number of visits to a point which provide the greatest efficiency for estimating the cumulative number of species in bottomland hardwood forest stands within the Mississippi Alluvial Valley, and to ascertain if increasing the number of visits to points is equivalent to adding more points. Because the total number of species detected in DEF were different between years, 39 species in 1991 and 55 species in 1992, we considered each year independently. Within each stand, we obtained bootstrap estimates of the mean cumulative number of species obtained from all possible combinations of six points and six visits (i.e., 36 means/stand). These bootstrap estimates were subjected to ANOVA; we modelled cumulative number of species as a function of the number of points visited, the number of visits to each point, and their interaction. As part of the same ANOVA we made an a priori, simultaneous comparison of the 15 possible reciprocal treatments (i.e., 1 point-2 visits vs. 2 points-1 visit, etc.). Results of analyses for each year were similar. Although no interaction was detected between the number of points and the number of visits, when reciprocals were compared, more points visited yielded significantly greater cumulative number of species than more visits to each point. Significant differences were detected among both the number of points visited and among the number of visits to a point. Scheffe's test of differences among means indicated that the cumulative number of species increased significantly with each added point, through five points, but six points did not differ from five points in 1991. Similarly, the cumulative number of species increased significantlywith each revisit, up to four visits, but four visits did not differ significantly from five visits. Starting with one point, which yielded about 33 percent of the total species pool when averaged among one through six points, each subsequent point resulted in an increase of about 9 percent, 5 percent, 3 percent, and 3 percent, respectively. Each sequential increase in the number of visits, however, only resulted in increases of 7 percent, 4 percent, 2 percent, and 2 percent of the total species pool.

Book chapter↗