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At least 541 records · Page 30Linked to original sources
USGS2024

Sod farms drive habitat selection of a migratory grassland shorebird during a critical stopover period

Migratory shorebirds are one of the fastest declining groups of North American avifauna. Yet, relatively little is known about how these species select habitat during migration. We explored the habitat selection of Buff-breasted Sandpipers ( Calidris subruficollis ) during spring and fall migration through the Texas Coastal Plain, a major stopover region for this species. Using tracking data from 118 birds compiled over 4 years, we found Buff-breasted Sandpipers selected intensively managed crops such as sod and short-stature crop fields, but generally avoided rangeland and areas near trees and shrubs. This work supports prior studies that also indicate the importance of short-stature vegetation for this species. Use of sod and corn varied by season, with birds preferring sod in spring, and avoiding corn when it is tall, but selecting for corn in fall after harvest. This dependence on cropland in the Texas Coastal Plain is contrary to habitat use observed in other parts of their non-breeding range, where rangelands are used extensively. The species' almost complete reliance on a highly specialized crop, sod, at this critical stopover site raises concerns about potential exposure to contaminants as well as questions about whether current management practices are providing suitable conditions for migratory grassland birds.

Texas↗
USGS1977

Fall migration of woodcock at Cape May, New Jersey

From 1968 to 1973, 2,337 American woodcock ( Philohela minor ) were banded during late fall on the Cape May Peninsula of southern New Jersey. Direct recovery rates averaged 3.6 percent for hatching-year birds and 1.7 percent for adults. Distribution of recoveries indicated that Cape May migrants wintered on the coastal plain of Virginia and North Carolina. Indirect recoveries showed that Peninsula woodcock originated from as far north as New England and eastern Canada. The percentage of woodcock seen which were caught by night-lighting averaged 2.5 times greater from a truck than on foot. Age-sex structure of ban dings was similar each year with the overall composition as follows: immaturemales, 57 percent; immature females, 28 percent; adult males, 10 percent; and adult females, 5 percent. Compared to the continental population, there was an unusually high proportion of immature woodcock at Cape May during late fall.

New Jersey↗
USGS1987

Breeding birds and vegetation structure in western North Dakota wooded draws

Populations and distribution of breeding birds occupying wooded draws were studied in a five-county region of western North Dakota during June 1982. Wooded draw vegetation was dominated by green ash, which occurred in 96% of the draws sampled. Chokecherry and juneberry were the most frequent shrub species. I recorded 49 bird species in the 30 draws censused. Rufous-sided towhee, brown-headed cowbird, house wren, and American goldfinch were the most numerous bird species present. Significant correlations were found between (1) the number of live trees and bird species evenness, (2) density of dead trees and bird species diversity and richness, (3) density of shrubs with bird species evenness, and (4) foliage volume in the high ground layer and bird species evenness.

Prairie Naturalist↗
USGS2015

Science foundation Chapter 5 Appendix 5.1: Case study shore birds: Western sandpipers ( Calidris mauri ) and American avocets ( Recurvirostra Americana )

Western sandpipers ( Calidris mauri ) are small (22-35 g) sexually dimorphic sandpipers, with males typically smaller than females. Western sandpipers frequently occur in mixed species flocks along with other Calidris species, including least sandpipers ( Calidris minutilla ) and dunlin ( Calidris alpina ), in the San Francisco Bay Estuary (SFBE) and are the most abundant shorebird species found from fall to spring. Western sandpipers are one of the most common shorebird species in SFBE, the Pacific Flyway, and North America overall. The largest concentrations of western sandpipers, and of most shorebirds, are found in the South Bay where large expanses of mudflats are exposed at low tide and managed and/or salt ponds are available for high tide roosting and feeding habitat (Warnock et al 2002, Warnock and Takekawa 1995). In recent years, there is some evidence that there has been a shift in shorebird numbers towards the North Bay, perhaps as large salt pond restoration projects provide interim mud flat habitat during the evolution towards tidal marsh habitat (Pitkin and Wood, 2011).

California↗
USGS1960

The trumpeter swan: its history, habits, and population in the U.S

This report on the trumpeter evolved from studies made from 1948 to 1957 when I served first as an assistant and later as manager, of the Red Rock Lakes Refuge. I have also drawn extensively on the records of the National Park Service, the U. S. Fish and Wildlife Service, and the National Museum in Washington, D. C. Other pertinent information bearing on the life history of the trumpeter swan in the United States has been extracted from published articles, unpublished reports and records, firsthand accounts and correspondence. This account includes a historical record of this bird in the United States and Alaska, an outline of its habits and characteristics in its native Rocky Mountain environment, and furnishes information necessary to guide its future.

North American Fauna↗
USGS2021

Implications of historical and contemporary processes on genetic differentiation of a declining boreal songbird: The rusty blackbird

The arrangement of habitat features via historical or contemporary events can strongly influence genomic and demographic connectivity, and in turn affect levels of genetic diversity and resilience of populations to environmental perturbation. The rusty blackbird ( Euphagus carolinus ) is a forested wetland habitat specialist whose population size has declined sharply (78%) over recent decades. The species breeds across the expansive North American boreal forest region, which contains a mosaic of habitat conditions resulting from active natural disturbance regimes and glacial history. We used landscape genomics to evaluate how past and present landscape features have shaped patterns of genetic diversity and connectivity across the species’ breeding range. Based on reduced-representation genomic and mitochondrial DNA, genetic structure followed four broad patterns influenced by both historical and contemporary forces: (1) an east–west partition consistent with vicariance during the last glacial maximum; (2) a potential secondary contact zone between eastern and western lineages at James Bay, Ontario; (3) insular differentiation of birds on Newfoundland; and (4) restricted regional gene flow among locales within western and eastern North America. The presence of genomic structure and therefore restricted dispersal among populations may limit the species’ capacity to respond to rapid environmental change.

Diversity↗
USGS2004

Estimating the use of morphometric measurements from museum specimens for sex determination in Mountain Plovers (Charadrius montanus)

The Mountain Plover ( Charadrius montanus ) is a shorebird species endemic to the dry, terrestrial ecosystems of the Great Plains and southwestern United States. Breeding Bird Survey data suggest that Mountain Plover populations have declined by >60% in the last 30 years. A better understanding of the population dynamics of the Mountain Plover is important in determining future management goals for this species. However, this effort is hampered by the inability to determine the sex of Mountain Plovers accurately under field conditions. In an effort to develop a simple method for sexing plovers in the hand, we measured external morphometric characteristics from 190 museum specimens of adult Mountain Plovers in alternate (breeding) plumage. Logistic regression and discriminant function analyses were performed on 10 external morphometric measurements (lengths of unflattened wing chord, 10th primary, central rectrix, outer rectrix, total head length, exposed culmen, culmen, bill depth, bill width, and tarsus). The results of these analyses indicated that Mountain Plover sexes were similar for all measures except culmen length. However, further analysis determined that culmen length accurately predicted sex in less than two-thirds of the specimens, suggesting that this measure is a poor predictor of sex in Mountain Plovers. Structurally, Mountain Plovers appear to be nearly identical between the sexes, and other methods of sexing birds (e.g., plumage characteristics, behavioral observations, or molecular markers) should be further assessed for devising a simple method for sexing Mountain Plovers under field conditions.

Western North American Naturalist↗
USGS1978

The California condor, 1966-1976: A Look at its Past and Future

The California condor (Gymnogyps californianus) was studied on about 900 field days between 1966 and 1976. In addition, some 1,000 items of literature, specimen records from 56 museums, and 3,500 reports of condor sitings by cooperators were analyzed. Distribution does not appear to have changed significantly since the 1930's, although there are some areas within the. species' range that have become unusable. Two subpopulations of condors exist, one occupying the Coast Range Mountains, and the other found in the Transverse Ranges, Tehachapi Mountains, and Sierra Nevadas. There are well-defined seasonal movements within each subpopulation area. The surviving, wild population was estimated to be 45 condors in 1976, a decline of about 20% since 1965 and probably over 50% since 1940. No reliable population estimates are available before the 1940's, but it appears that a major decline occurred between 1880 and 1920. Shooting and specimen collecting were the primary causes of the early decline, and shooting continued as a major problem into the 1960's. Recent declines are a result of inadequate production; annual surveys indicate that only 16 young have been produced since 1968. Causes of low production are unknown but inadequate food supply, environmental contaminants, and disturbance from air traffic and petroleum extraction are implicated. A recovery plan for the condor is in operation; steps have been taken to supplement food supplies, preserve nesting and roosting habitat, and protect surviving birds from man-caused mortality or disturbance. The condor's prospects of recovery in its natural habitat seem bleak; a captive propagation program is proposed to supplement wild production.

North American Fauna↗
USGS2022

Nest remains are insufficient to identify predators of waterfowl nests

Context: Nest predation is a leading cause of nest failure for most ground-nesting birds. Methods that allow for accurate classification of fate and identification of predators are important for understanding productivity and conservation strategies. Past studies have used a visual inspection of nest remains to determine nest fate and predict predator identity. Most formal assessments of these methods have addressed small-bodied birds nesting in trees or shrubs, and have revealed that use of evidence at nests can be relatively accurate for determining nest fate but may lead to incorrect conclusions regarding predator identity. However, few have tested the latter hypothesis for larger ground-nesting birds with precocial young. Aim: We aimed to evaluate a classification system developed for determining nest fate and identifying predators of waterfowl nests, at both the scale of individual nests and across the study area. Methods: From 2016 to 2020, we located 989 blue-winged teal ( Spatula discors ), mallard ( Anas platyrhynchos ) and gadwall ( Mareca strepera ) nests in central North Dakota. We placed cameras at a subset of 249 nests and recorded evidence of nest remains at depredated nests. Key results: The most common predators were American badgers ( Taxidea taxus ), followed by striped skunks ( Mephitis mephitis ), raccoons ( Procyon lotor ) and red foxes ( Vulpes vulpes ). Using evidence of nest remains, we determined nest fates with high accuracy (98.0%). However, evidence of nest remains was only sufficient for identifying predators at 50% of nests, and the classification system was correct only 69.7% of the time. The predicted proportion of predators across the study area differed between the classification system and our video evidence as well. Conclusions: The accuracy of predator identifications based upon the classification system that we evaluated was not supported at any scale. Implications: Our results suggest that evidence of nest remains can be used to determine nest fate for large-bodied precocial, ground-nesting birds, but accurate identification of nest predators will require alternative methods such as nest cameras.

Wildlife Research↗
USGS1976

Report of the American Ornithologists' Union Committee on Conservation 1975-76

This Committee's report for 1974-75 (Marshall et al. 1975, Auk 92 (4, Suppl.): lB-16B) summarized activities affecting bird conservation in the United States and Canada since 1973, including new legislation, international activities, avian conflicts with industrial and population growth, and habitat preservation. It also summarized the status of many of the endangered birds of North America, and a few critically endangered species elsewhere. The concern expressed in the report for greater participation of scientists outside government in the affairs of government has led to the formation of an AOU Committee on Public Responsibility. This report focuses on avian conservation problems in two areas, Puerto Rico and the islands of the Bering Sea. Both areas have conservation problems that are significant to ornithologists, there have been major new developments in the status of the birds and their habitats in these areas in the last few years, yet neither area has received the attention this committee feels it deserves. The Committee thanks Noel Snyder and George Gee for their contributions to this report.

The Auk↗
USGS1983

Impacts of forest herbicides on wildlife: Toxicity and habitat alteration

This paper begins with a review of both laboratory and field studies on tbe possible direct toxic effects of herbicides on terrestrial vertebrates, primarily birds and mammals. Alteration of the palatability of forage and changes in reproductive success are also discussed. Emphasis is placed on the use of herbicides in forestry; studies dealing with agricultural systems are referenced where appropriate. The indirect effects of herbicides on wildlife-habitat are then conceptualized and quantified using data from a 3-year study on effects of phenoxy and glyphosate herbicides on bird and small mammal communities in western Oregon. Data on density and habitat use are presented and compared with data available from other geographic regions.

Transactions of the North American Wildlife and Na↗
USGS1991

Wigeongrass ( Ruppia maritima ): a literature review

Wigeongrass (Ruppia maritima L.) is a submersed macrophyte of nearly cosmopolitan distribution and worldwide importance as a waterfowl food. Unfortunately, the plant no longer inhabits vast areas disturbed by human activities. Taxonomic status of the plant is uncertain, especially in North America. In mild climates, in habitats subject to environmental extremes, the plant behaves as an annual (vegetation perishes), or as a perennial in deeper, more stable habitats (some vegetative parts grow year round). Drupelets (seeds) provide a mechanism for wigeongrass to survive periods of drought and excessive water salinity. These sexual propagules can be washed ashore or carried by birds or fish for long distances.Wigeongrass mostly occurs in temporarily to permanently flooded mesohaline-hyperhaline estuarine wetlands, but it also occurs inland in fresh to hypersaline palustrine and lacustrine wetlands. Most populations inhabit warm, relatively unpolluted, and well lit waters <2.0 m deep where fetches and wave action are not great. The species is probably best adapted to stable water levels but can tolerate significant water level fluctuations, including periodic exposure in tidal areas. Robust growth occurs in areas of slow current. Wigeongrass is alone among the submersed North American angiosperms in tolerance to high salinity, but it is likely at a competitive disadvantage among specialist taxa in soft or acidic waters. The species grows in nearly all common bottom substrates, but growth is favored by aerobic and low H 2 S conditions. Turbidity frequently limits wigeongrass growth in waters overlying easily suspendible bottom substrates.Wigeongrass often occurs in monotypic stands, yet grows with many other submersed and emergent macrophytes. Dominance in certain wetlands sometimes alternates with dominance by other submersed macrophytes as salinities, seasonal temperature cycles, or other environmental factors change. The shading effect of metaphytic, planktonic, or epiphytic algae often reduces production.Wigeongrass and its detritus provide food and cover for a large invertebrate biota, although direct consumption of the living plants is minimal. Wigeongrass beds in coastal wetlands are heavily used by fish. The plant is recognized worldwide as an important food of migrant and wintering waterfowl, wading birds, and shorebirds. In subtropical climates, wintering waterfowl can quickly consume entire stands.Propagation and management of wigeongrass has occurred for nearly 60 years in the southern and eastern United States. During the seventies and eighties, sophisticated water level and salinity management techniques have been developed to encourage growth of the plant.Future research should concentrate on determining the means to reduce light-limiting turbidity in many wetland types; understanding the ways in which human activities on and near wetlands affect wigeongrass production; and developing reliable and predictable techniques to stimulate wigeongrass production by water level manipulations and other means in different environmental settings. Trophic interactions and the effects of biomanipulation of fish populations in managed wigeongrass habitat--now little understood--also require more study.

Fish and Wildlife Research↗
USGS2016

Range expansion by Passer montanus in North America

Passer montanus became established in a small area of central North America following its introduction in 1870. P. montanus underwent minimal range expansion in the first 100 years following introduction. However, the North American population of P. montanus is now growing in size and expanding in geographic distribution, having expanded approximately 125 km to the north by 1970. We quantify the distance of spread by P. montanus from its introduction site in the greater St. Louis, Missouri-Illinois, USA area, using distributional (presence) data from the National Audubon Society Christmas Bird Count surveys for the period of 1951 to 2014. Linear regressions of the average annual range center of P. montanus confirmed significant shifts to the north at a rate of 3.3 km/year ( P < 0.001) km/year. Linear regressions of the linear and angular distance of range center indicates significant northern movement (change in angle of mean range center; P < 0.001) since 1951. Our results quantify the extent of a northward range expansion, and suggesting a probable spread of this species northward.

Biological Invasions↗
USGS2011

Phylogeography of a vanishing North American songbird: The Painted Bunting (Passerina ciris)

The breeding distribution of Painted Buntings ( Passerina ciris ) is comprised of two allopatric populations separated by a 550-km distributional gap in the southeastern United States. Curiously, the boundary between the two recognized P. ciris subspecies does not separate the two allopatric breeding populations but instead runs roughly through the center of the interior population. Genetic relationships among these subspecies, and the allopatric breeding populations of Painted Bunting, have not been assessed. Given the recent decline in overall abundance of this species, such an assessment is warranted. We sampled birds from 15 localities (138 individuals) and identified 35 distinct haplotypes, six belonging to the Atlantic Coast population and 26 to the interior population, with three shared by both populations. AMOVA results showed that a significantly greater portion of the total genetic variance is explained when grouping birds by the interior and Atlantic Coast populations rather than by subspecies. Furthermore, our data indicate that the Atlantic Coast and interior populations represent independently evolving taxa, with no measureable gene flow between them. Although recently diverged (26,000–115,000 years ago), these isolated bunting populations represent incipient species. For development of conservation strategies, we suggest that the Atlantic Coast and interior populations be recognized as separate management units.

Conservation Genetics↗
USGS1998

Waterfowl in the prairie pothole region

The prairie pothole region of the northern Great Plains is one of the most important areas for duck reproduction in North America. The region produces, on average, 50% of the primary species of game ducks on the continent (Smith 1995), yet accounts for only 10% of the waterfowl breeding habitat in North America (Smith et al. 1964). Twelve of the 34 species of North American ducks are common breeders in the region. For seven species—mallard, gadwall, blue-winged teal, northern shoveler, northern pintail, redhead, and canvasback—the prairie pothole region accounts for more than 60% of the breeding population (Smith 1995). The region is also a major migration corridor during fall and spring for other ducks, geese, and other water birds.

Book chapter↗
USGS2002

Morphometric changes in Yellow-headed Blackbirds during summer in central North Dakota

Temporal stability of morphometric measurements is desirable when using avian morphology as a predictor of geographic origin. Therefore, to assess their temporal stability, we examined changes in morphology of Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) from central North Dakota during summer. Measurements differed among age classes and between sexes. As expected, due to growth and maturation, measurements on hatching-year birds increased over summer. Measurements of adult plumage fluctuated with prebasic molt and exhibited age-specific discontinuities. Body mass of adult birds increased over summer, whereas both culmen length and skull length decreased. Only body length and length of internal skeletal elements were temporally stable in adult Yellow-headed Blackbirds.

Western North American Naturalist↗
USGS2021

Revealing migratory path, important stopovers and non-breeding areas of a boreal songbird in steep decline

The Olive-sided Flycatcher (Contopus cooperi) is a steeply declining aerial insectivore with one of the longest migrations of any North American passerine. We deployed light-level geolocators and archival GPS tags on breeders in boreal Alaska to determine migratory routes, important stopovers and non-breeding locations. Data from 16 individuals revealed a median 23,555 km annual journey (range: 19,387, 27,292 km) over 95 days (range: 83, 139 days) with wintering occurring in three regions of South America (NW Colombia/Ecuador, central Peru and W Brazil/S Peru). We developed a new method to identify “Important Stopovers” by quantifying intensity of use (a function of bird numbers and stop durations) along migratory routes. We identified 13 Important Stopovers that accounted for ~66% of the annual migratory period, suggestive of refueling activities. Some sites coincided with key areas previously identified for other Neotropi- cal-Nearctic migrants. Percent land “protected” at Impor- tant Stopovers, as defined by IUCN, ranged from 3.8% to 49.3% (mean [95% CI]: 17.3% [9.6, 25.0]). Total migration speed did not differ by season (median: 255 km day-1, range: 182, 295km day-1), despite greater spring travel dis- tances. Birds with longer non-breeding periods, however, migrated north faster. Climate-driven mismatches in migratory timing may be less of a concern for western than for eastern flycatcher populations, given recent con- generic analyses (C. sordidulus, C. virens). However, accel- erated high-latitude changes, may nonetheless impact boreal breeders.

Alaska↗