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At least 631 records · Page 35Linked to original sources

USGS2008

A double-observer method to estimate detection rate during aerial waterfowl surveys

We evaluated double-observer methods for aerial surveys as a means to adjust counts of waterfowl for incomplete detection. We conducted our study in eastern Canada and the northeast United States utilizing 3 aerial-survey crews flying 3 different types of fixed-wing aircraft. We reconciled counts of front- and rear-seat observers immediately following an observation by the rear-seat observer (i.e., on-the-fly reconciliation). We evaluated 6 a priori models containing a combination of several factors thought to influence detection probability including observer, seat position, aircraft type, and group size. We analyzed data for American black ducks (Anas rubripes) and mallards (A. platyrhynchos), which are among the most abundant duck species in this region. The best-supported model for both black ducks and mallards included observer effects. Sample sizes of black ducks were sufficient to estimate observer-specific detection rates for each crew. Estimated detection rates for black ducks were 0.62 (SE = 0.10), 0.63 (SE = 0.06), and 0.74 (SE = 0.07) for pilot-observers, 0.61 (SE = 0.08), 0.62 (SE = 0.06), and 0.81 (SE = 0.07) for other front-seat observers, and 0.43 (SE = 0.05), 0.58 (SE = 0.06), and 0.73 (SE = 0.04) for rear-seat observers. For mallards, sample sizes were adequate to generate stable maximum-likelihood estimates of observer-specific detection rates for only one aerial crew. Estimated observer-specific detection rates for that crew were 0.84 (SE = 0.04) for the pilot-observer, 0.74 (SE = 0.05) for the other front-seat observer, and 0.47 (SE = 0.03) for the rear-seat observer. Estimated observer detection rates were confounded by the position of the seat occupied by an observer, because observers did not switch seats, and by land-cover because vegetation and landform varied among crew areas. Double-observer methods with on-the-fly reconciliation, although not without challenges, offer one viable option to account for detection bias in aerial waterfowl surveys where birds are distributed at low density in remote areas that are inaccessible by ground crews. Double-observer methods, however, estimate only detection rate of animals that are potentially observable given the survey method applied. Auxiliary data and methods must be considered to estimate overall detection rate.

Journal of Wildlife Management↗

USGS2009

Paraphyly of Cinclodes fuscus (Aves: Passeriformes: Furnariidae): Implications for taxonomy and biogeography

The Andes are a hotspot of global avian diversity, but studies on the historical diversification of Andean birds remain relatively scarce. Evolutionary studies on avian lineages with Andean–Patagonian distributions have focused on reconstructing species-level phylogenies, whereas no detailed phylogeographic studies on widespread species have been conducted. Here, we describe phylogeographic patterns in the Bar-winged Cinclodes ( Cinclodes fuscus ), a widespread and common species of ovenbird (Furnariidae) that breeds from Tierra del Fuego to the northern Andes. Traditionally, C. fuscus has been considered a single species composed of nine subspecies, but its long and narrow range suggests the possibility of considerable genetic variation among populations. Sequences of two mitochondrial genes revealed three discrete and geographically coherent groups of C. fuscus , occupying the southern, central, and northern Andes. Surprisingly, phylogenetic analyses indicated that these groups were more closely related to other species of Cinclodes than to each other. Relationships of the southern and northern C. fuscus clades to other species of Cinclodes were straightforward; in combination with available information on plumage, behavioral, and vocal variation, this suggests that each should be recognized as a distinct biological species. The central Andean group was paraphyletic with respect to C. oustaleti , and relationships among these taxa and C. olrogi were poorly resolved. We suggest that the central Andean C. fuscus should also be considered a different species, pending new information to clarify species limits in this group. These new phylogenetic data, along with recently developed methods, allowed us to review the biogeography of the genus, confirming southern South America and the central Andes as important areas for the diversification of these birds.

Molecular Phylogenetics and Evolution↗

USGS1995

Northern Pintail ( Anas acuta )

The Northern Pintail is a medium-sized dabbling duck of slender, elegant lines and conservative plumage coloration. It is circumpolar in distribution and abundant in North America, with core nesting habitat in Alaska and the Prairie Pothole Region of southern Canada and the northern Great Plains. Breeders favor shallow wetlands interspersed throughout prairie grasslands or arctic tundra. An early fall migrant, the species arrives on wintering areas beginning in August, after wing molt, often forming large roosting and feeding flocks on open, shallow wetlands and flooded agricultural fields. The birds consume grains, marsh plant seeds, and aquatic invertebrates throughout the fall and winter. Northern Pintails are among the earliest nesting ducks in North America, beginning shortly after ice-out in many northern areas. Individuals form new pair bonds each winter but are highly promiscuous during the nesting season, with mated and unmated males often involved in vigorous, acrobatic Pursuit Flights. Annual nest success and productivity vary with water conditions, predation, and weather. Females build nests on the ground, often long distances from water. Only the female incubates; her mate leaves shortly after incubation begins. Ducklings hatch together in one day, follow the female to water after a day in the nest, and fledge by July or August. Adults and ducklings consume mainly aquatic invertebrates during the breeding season. Predators and farming operations destroy many thousands of Northern Pintail nests annually; farming has also greatly reduced the amount of quality nesting cover available. Winter habitats are threatened by water shortages, agricultural development, contamination, and urbanization. Periods of extended drought in prairie nesting regions have caused dramatic population declines, usually followed by periods of recovery. Over the long term, however, the continental population of Northern Pintails has declined significantly from 6 million birds in the early 1970s to less than 3 million in the late 1980s and early 1990s. However, new conservation measures, such as habitat restoration and enhancement of agricultural lands, as well as prudent harvest restrictions, suggest that Northern Pintails should have a secure future in North America.

Book chapter↗

USGS2011

Developing Gyrfalcon surveys and monitoring for Alaska

We developed methods to monitor the status of Gyrfalcons in Alaska. Results of surveys and monitoring will be informative for resource managers and will be useful for studying potential changes in ecological communities of the high latitudes. We estimated that the probability of detecting a Gyrfalcon at an occupied nest site was between 64% and 87% depending on observer experience and aircraft type (fixed-wing or helicopter). The probability of detection is an important factor for estimating occupancy of nesting areas, and occupancy can be used as a metric for monitoring species' status. We conclude that surveys of nesting habitat to monitor occupancy during the breeding season are practical because of the high probability of seeing a Gyrfalcon from aircraft. Aerial surveys are effective for searching sample plots or index areas in the expanse of the Alaskan terrain. Furthermore, several species of cliff-nesting birds can be surveyed concurrently from aircraft. Occupancy estimation also can be applied using data from other field search methods (e.g., from boats) that have proven useful in Alaska. We believe a coordinated broad-scale, inter-agency, collaborative approach is necessary in Alaska. Monitoring can be facilitated by collating and archiving each set of results in a secure universal repository to allow for statewide meta-analysis.

Alaska↗

USGS1982

Simulations of seabird damage and recovery from oilspills in the northern Gulf of Alaska.

If an oilspill contacts a colony of glaucous-winged gulls Larus hyperboreus, reducing the population by 50%, the population is expected to recover to its pre-spill level in c.20 yr. For common murres Uria aalge, this same situation yields a recovery time of c.70 yr. Assuming that oil is found in the study area, and based on the expected number of oilspills to occur and contact these colonies during the lease lifetime, and assuming that each oilspill contact causes a fractional population loss of 0.95, the probability of reducing the population to some fraction of its initial level was calculated. For gulls, only a 10% change of population reduction to less than one-half the pre-spill level was calculated for the lease lifetime. For murres, only a 4% change of similar reduction was calculated.-from Authors

Journal of Environmental Management↗

USGS1992

The structure, dynamics, and chemical composition of noneruptive plumes from Mount St. Helens, 1980-1988

From May 1980 to September 1988, more than 1000 fixed-wing aircraft flights were made with a correlation spectrometer to measure the sulfur dioxide flux from Mount St. Helens volcano. These flights also provided valuable data on the structure and dynamics of noneruptive plumes emanating from Mount St. Helens. During 1980 and part of 1981, an infrared spectrometer was also used to measure carbon dioxide emission rates. At distances up to 25 km from Mount St. Helens, plume widths can range up to 20 km or more, with width/thickness ratios from 3 to about 30. Maximum sulfur dioxide concentrations in these plumes depend on wind speed and are typically under 5 ppm and usually 1 ppm or less. Close examination of the plume data reveals that the characteristics of quiescent plumes from Mount St. Helens are strongly affected by certain meteorological conditions such as thermal and wind stratification in the troposphere, as well as by the topography of the volcano. ?? 1992.

Journal of Volcanology and Geothermal Research↗

USGS1998

Status of the White-faced Ibis: Breeding colony dynamics of the Great Basin population, 1985-1997

The status of the White-faced Ibis (Plegadis chihi) in the Great Basin is of concern because of its small population size and the limited and dynamic nature of its breeding habitat. We analyzed existing annual survey data for the White-faced Ibis breeding in the Great Basin and surrounding area for 1985-1997. Methods varied among colonies and included flight-line counts and fixed-wing aircraft and helicopter surveys. The number of White-faced Ibis breeding pairs in the Great Basin area has nearly tripled since 1985, despite years of severe flooding and drought at major breeding areas. This growth is reflected in both peripheral (i.e., Oregon, California, Idaho) and core (i.e., Nevada and Utah) components of the population. Our data on colony dynamics in Oregon and Nevada illustrate the ability of the highly nomadic White-faced Ibis to compensate for poor conditions at traditional colony sites by moving among colonies and rapidly colonizing newly available wetlands. We suggest that the White-faced Ibis would benefit from a landscape mosaic of well-distributed peripheral wetlands and persistent colony sites. The nomadic nature of the White-faced Ibis and the dynamic nature of their breeding habitat necessitates that wetland management decisions and population monitoring be conducted in a regional context.

Waterbirds↗

USGS1999

Loss from harlequin ducks of abdominally implanted radio transmitters equipped with percutaneous antennas

We documented extrusion and loss of abdominally implanted radio transmitters with percutaneous antennas from adult female Harlequin Ducks (Histrionicus histrionicus). Birds were captured during wing molt (late August to mid-September) in 1995-1997. Of 44 Harlequin Ducks implanted with radios and recaptured, 7 (16%) had lost their transmitters and 5 (11%) had radios in the process of extruding. Most (11 of 12) extrusions and losses occurred in birds implanted with radios in 1996 and recaptured in 1997. We suggest that transmitter extrusions and losses were due largely to changes in transmitter design made between 1095 and 1996. Transmitters implanted in 1996 were cylindrical rather than spherical, had a flat end with an abrupt edge, and the lower portion of the antenna was reinforced. Radio losses occurred after the 7-mo monitoring period and caused no apparent harm to the birds. Investigators using implanted radios with percutaneous antennas for long-term projects should be aware of the potential for radio extrusion and should minimize the problem by using transmitters that have no sharp edges and that are wide, rather than narrow.

Journal of Field Ornithology↗

USGS2004

Composition of breeding bird communities in Gulf Coast Chenier Plain marshes: Effects of winter burning

Marsh managers along the Gulf Coast Chenier Plain frequently use winter burns to alter marsh vegetation and improve habitat quality for wintering waterfowl. However, effects of these burns on marsh avifauna are not well documented. We recorded abundances of breeding bird species and vegetation structure in burned and unburned control marshes during one breeding season before (1996) and two breeding seasons after (1997, 1998) experimental winter burns. We used non-metric multidimensional scaling analysis to assess the extent and direction of changes in bird community compositions of burned and unburned control marshes and to investigate the influence of vegetation structure on bird community composition. Overall, we found that Seaside Sparrows (Emberizidae: Ammodramus maritimus [Wilson]) and Red-winged Blackbirds and Boat-tailed Grackles (Icteridae: Agelaius phoeniceus [L.] and Quiscalus major Vieillot, respectively) comprised > 85% of observed birds. In burned marshes during the first breeding season following experimental burns (1997), icterid abundance increased while Seaside Sparrow abundance decreased relative to pre-burn (1996) conditions. This pattern was reversed during the second breeding season post-burn. No obvious patterns of change in avian abundance were detected in unburned control marshes over the 3-year period. Qualitative changes in breeding bird community composition were related to effects of winter burning on percent cover of dead vegetation and Spartina patens (Aiton) Muhl.

Southeastern Naturalist↗

USGS2006

Proximate and landscape factors influence grassland bird distributions

Ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. We examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of high conservation concern, in the Sheyenne National Grassland in North Dakota, USA. The Grassland contains a diverse array of grassland and woodland habitats. We surveyed breeding birds on 2015 100 m long transect segments during 2002 and 2003. We modeled the occurrence of 19 species in relation to habitat features (percentages of grassland, woodland, shrubland, and wetland) within each 100-m segment and to tree cover within 200-1600 m of the segment. We used information-theoretic statistical methods to compare models and variables. At the proximate scales, tree cover was the most important variable, having negative influences on 13 species and positive influences on two species. In a comparison of multiple scales, models with only proximate variables were adequate for some species, but models combining proximate with landscape information were best for 17 of 19 species. Landscape-only models were rarely competitive. Combined models at the largest scales (800-1600 m) were best for 12 of 19 species. Seven species had best models including 1600-m landscapes plus proximate factors in at least one year. These were Wilson's Phalarope (Phalaropus tricolor), Sedge Wren (Cistothorus platensis), Field Sparrow (Spizella pusilla), Grasshopper Sparrow (Ammodramus savannarum), Bobolink (Dolychonix oryzivorus), Red-winged Blackbird (Agelaius phoeniceus), and Brown-headed Cowbird (Molothrus ater). These seven are small-bodied species; thus larger-bodied species do not necessarily respond most to the largest landscapes. Our findings suggest that birds respond to habitat features at a variety of scales. Models with only landscape-scale tree cover were rarely competitive, indicating that broad-scale modeling alone, such as that based solely on remotely sensed data, is likely to be inadequate in explaining species distributions. ?? 2006 by the Ecological Society of America.

Ecological Applications↗

USGS2000

Macromoths of northwest forests and woodlands

The macromoths are a group of families within the order Lepidoptera. The macromoths in the woodlands and forests of the Pacific Northwest are represented by 1,200 species in 12 families: Arctiidae, Dioptidae, Drepanidae, Epiplemidae, Geometridae, Lasiocampidae, Lymantriidae, Noctuidae, Notodontidae, Saturniidae, Sphingidae, and Thyatiridae. In addition to the macromoths, the Lepidoptera are represented by the butterflies and skippers, and the micromoths. Butterflies possess a knob at the tip of the antennae while the tip of the antennae in skippers is typically hooked. The tip of the antennae in macromoths and micromoths is tapered. The differences between macromoths and micromoths is not literally based on size as the names suggest but rather in details of the female reproductive tract and wing venation. These details are discussed and illustrated in most texts on general entomology (Borror et al. 1989) and in books about Lepidoptera (Covell 1984).

California;Oregon;Washington;Idaho;Montana;British↗

USGS2011

Notes on the geology and meteorology of sites infected with white-nose syndrome before July 2010 in Southeastern United States

Since 2006, numerous bat colonies in North America have experienced unusually high incidences of mortality. In these colonies, bats are infected by a white fungus named Geomyces destructans, which has been observed on bat muzzles, noses, ears, and (or) wings. Although it is not exactly certain how and why these bats are dying, this condition has been named white-nose syndrome (WNS). WNS appears to have spread from an initial infection site at a cave in New York, and was first identified south of Pennsylvania during January 2009. By the end of June 2010, 41 infected sites had identified in the states of West Virginia, Maryland, Delaware, Virginia, and Tennessee. Most of these sites are natural caves in limestone of either Cambrian-Ordovician age or Silurian-Devonian age. Published air temperature values in these WNS-infected caves range from -3.3 to 15.6 °C, and humidity measurements range from 68 to 100 %.

Indiana;Kentucky;Maryl;North Carolina;Ohio;Pennsyl↗

USGS2013

Endozoochory of seeds and invertebrates by migratory waterbirds in Oklahoma, USA

Given their abundance and migratory behavior, waterbirds have major potential for dispersing plants and invertebrates within North America, yet their role as vectors remains poorly understood. We investigated the numbers and types of invertebrates and seeds within freshly collected faecal samples (n = 22) of migratory dabbling ducks and shorebirds in November 2008 in two parts of Lake Texoma in southern Oklahoma. Killdeer Charadrius vociferus were transporting a higher number and diversity of both plants and invertebrates than the green-winged teal Anas carolinensis. Ten plant taxa and six invertebrate taxa were identified to at least genus level, although viability was not confirmed for most of these taxa. Bryozoan statoblasts (from four species not previously recorded from Oklahoma) were especially abundant in killdeer faeces, while the ostracod Candona simpsoni was detected as a live adult in torpor in the teal faeces. Cyperaceae and Juncaceae were the most abundant plant families represented and Cyperus strigosus seeds germinated after extraction from killdeer faeces. This snapshot study underlines the importance of waterbirds as vectors of passive dispersal of many organisms and the need for more research in this discipline.

Oklahoma↗

USGS2014

Pacific Continental Shelf Environmental Assessment (PaCSEA): aerial seabird and marine mammal surveys off northern California, Oregon, and Washington, 2011-2012

Marine birds and mammals comprise an important community of meso- and upper-trophic-level predators within the northern California Current System (NCCS). The NCCS is located within one of the world’s four major eastern boundary currents and is characterized by an abundant and diverse marine ecosystem fuelled seasonally by wind-driven upwelling which supplies nutrient-rich water to abundant phytoplankton inhabiting the surface euphotic zone. The oceanographic conditions throughout the NCCS fluctuate according to well-described seasonal, inter-annual, and decadal cycles. Such oceanographic variability can influence patterns in the distribution, abundance, and habitat use among marine birds and mammals. Although there are an increasing number of studies documenting distributions and abundances among birds and mammals in various portions of the NCCS, there have been no comprehensive, large-scale, multi-seasonal surveys completed throughout this region since the early 1980s (off northern California; Briggs et al. 1987) and early 1990s (off Oregon and Washington; Bonnell et al. 1992, Briggs et al. 1992, Green et al. 1992). During 2011 and 2012, we completed the Pacific Continental Shelf Environmental Assessment (PaCSEA) which included replicated surveys over the continental shelfslope from shore to the 2000-meter (m) isobath along 32 broad-scale transects from Fort Bragg, California (39° N) through Grays Harbor, Washington (47° N). Additionally, surveys at a finer scale were conducted over the continental shelf within six designated Focal Areas: Fort Bragg, CA; Eureka, CA; Siltcoos Bank, OR; Newport, OR; Nehalem Bank, OR; and Grays Harbor, WA. We completed a total of 26,752 km of standardized, low-elevation aerial survey effort across three bathymetric domains: inner-shelf waters (<100-m depth), outer shelf waters (100 – 200-m depth) and continental slope waters (200 – 2000-m depth). Survey effort was similar among seasons (winter, summer, and fall) and between years and varied according to the three bathymetric domains: 47% (12,646 km) covered the continental slope, 33% (8887 km) covered the inner-shelf (0 – 100-m depth), and 20% (5,219 km) covered the outer-shelf. Overall, we recorded 15,403 sightings of 59,466 individual marine birds (12 families, 54 species). During winter, seven species groupings comprised >90% of the total number of birds counted (19,033) with Common Murres (Uria aalge) representing the majority of individuals counted (70.4% of total). The remaining six most abundant taxa included: Surf/White-winged Scoters (Melanitta perspicillata/M. fusca; 4.8% of total), Herring/Thayer’s Gulls (Larus argentatus/L. thayeri; 3.8% of total), Cassin’s Auklets (Ptychoramphus aleuticus; 3.8% of total), Glaucous-winged Gulls (Larus glaucescens; 3.7% of total), Black-legged Kittiwakes (Rissa tridactyla; 2.0% of total), and Western Gulls (Larus occidentalis; 1.9% of total). During summer, five species comprised >95% of the total number of birds counted (17,063) with the majority comprised of Common Murres (54.1% of total) and Sooty Shearwaters (Puffinus griseus; 34.4% of total). The remaining most abundant three taxa included: Fork-tailed Storm-Petrels (Oceanodroma furcata; 3.3% of total), Western Gulls (2.1% of total), and Leach’s Storm-Petrels (Oceanodroma leucorhoa; 1.1% of total). During fall, nine species comprised >85% of the total number of birds counted (23,376) with the majority comprised of Common Murres (50.0% of total) and Sooty Shearwaters (10.5% of total). The remaining seven taxa included Cassin’s Auklets (5.2% of total), Surf/White-winged Scoters (5.1% of total), Fork-tailed Storm-Petrels (3.8% of total), Red/Red-necked Phalaropes (Phalaropus fulicarius/P. lobatus; 3.2% of total), California Gulls (Larus californicus; 3.1% of total), Northern Fulmars (Fulmarus glacialis; 2.7% of total), and Sabine’s Gulls (Xema sabini; 2.2% of total). Throughout the entire PaCSEA survey area, average densities (± SE) at sea for all marine birds combined were similar between fall (23.7 ± 1.9 birds km -2 ) and winter (24.0 ± 1.9 birds km -2 ) and least during summer (16.3 ± 2.2 birds km -2 ). Marine bird densities at sea varied according to bathymetric domain and season. Throughout the entire PaCSEA study area average densities (± SE) for all marine birds combined were greatest over the inner-shelf domain (<100-m depth) during fall (49.4 ± 5.0 birds km -2 ) and similar during winter (37.4 ± 4.6 birds km -2 ) and summer (37.5 ± 6.4 birds km -2 ). Within the outer-shelf domain (100 – 200-m depth), average densities for all marine birds combined were greatest during winter (34.6 ± 4.2 birds km-2), lesser during fall (16.2 ± 1.7 birds km-2), and least during summer (6.9 ± 1.1 birds km-2). Within the farthest offshore waters over the continental slope domain (200 – 2000-m depth) average densities for all marine birds combined were greatest during fall (10.0 ± 2.2 birds km -2 ) and winter (9.3 ± 1.5 birds km -2 ), and lesser during summer (6.2 ± 1.4 birds km -2 ). We observed 16 cetacean species and five pinniped species. Among the Mysticeti (baleen whales), humpback whales (Megaptera novaeangliae) were most frequently observed (114 sightings of 264 individuals) during summer and fall mostly over the outer-shelf and slope waters, however, individuals were also seen within the Siltcoos, Nehalem, Fort Bragg, and Eureka Focal Areas. We recorded 11 Odontoceti (toothed whale) species. Harbor porpoises (Phocoena phocoena) were the most frequently sighted (164 sightings of 270 individuals). Harbor porpoises were present year-round and most frequently sighted within the inner-shelf domain throughout the entire study area in all seasons. Harbor porpoises occurred in all six Focal Areas, with noteworthy aggregations within the Eureka, Siltcoos, and Grays Harbor Focal Areas. We recorded 246 sightings of 375 individual pinnipeds (5 species). California sea lions (Zalophus californianus) were the most frequently sighted and were present year-round with slightly more sightings recorded during the fall. California sea lions showed a decreasing frequency of sightings and relative abundance with distance from shore across the bathymetric domains surveyed, being most frequently observed over the inner-shelf. Northern elephant seals (Mirounga angustirostris), harbor seals (Phoca vitulina), and northern fur seals (Callorhinus ursinus) were observed occasionally during all seasons with harbor seals occurring nearshore (usually within 10 km of the coast) and northern fur seals almost exclusively beyond the shelf break (> 200-m depth), especially during winter off Oregon and Washington. Northern (Steller’s) sea lions (Eumetopias jubatus) were uncommonly sighted during winter and fall.

California;Oregon;Washington↗

USGS1980

Airborne-biogeochemical survey test-case results

Airborne spectroradiometer surveys over several forest-covered sulfide bodies indicate that mineralization has affected the overlying vegetation; anomalous spectral reflectivity properties can be detected in the vegetation using appropriate remote-sensing interments and data-reduction techniques. Mineralization induces subtle changes in the shape of the chlorophyll a and b absorption spectrum between 550 and 750 nm. The observed spectral variations appear specifically to be on the wings of the broad red chlorophyll bars, centered at about 680 nm.

Sixth Annual Pecora Symposium and Exposition↗

USGS1992

Geographic Variation in Hirundo pyrrhonota (Cliff Swallow) from Northern North America

The number of subspecies recognized in Hirundo pyrrhonota Vieillot (Cliff Swallow) from Alaska, Canada, and the northern contiguous United States ranges from one (Peters 1960) to three (e.g., Jewett et al. 1953, Oberholser, 1920, breeding from central Alaska to the central Great Basin, and two disjunct populations of nominate pyrrhonota , breeding on the west coast and east of the Rocky Mountains. Although various authors have reported measurements of wing chord, they have not provided quantitative data for other plumage characters, and they disagree in the characterizations and ranges of the subspecies they recognize. Because of this, I reviewed the geographic variation among the northern populations. My study is confined to specimens from Alaska, Canada, and the contigeous United States south to Merced County in California, both slopes of the Rocky Mountains from Montana and Colorado, and northern half of the eastern United States from Kansas east to Virginia (Figure 1). The A.O.U. (1957) gave the breeding range of hypopolia as extending from Alaska and Mackenzie to southeastern British Columbia, the eastern parts of Washington, Oregon, and central-eastern California, central Nevada, northern Utah, Montana, and northwestern Wyoming, and the range of nominate pyrhonota as from southwestern British Columbia, western Oregon and Washington to southern California, southern Nevada, southern and eastern Utag, and east of the Rocky Mountains. I excluded specimens of H. p. ganieri Phillips, 1986, a subspecies (Browning 1990) that breeds from at least west-central Tennessee to Texas, and H. p. tachina Oberholser, 1903 (sensu Phillips 1986), which breeds north to central California, Utah, Arizona, and new Mexico. I follow Phillips (1973) for the use of the generic name Hirundo for the Cliff Swallow, Hellmayr (1935) for the use of the specific name pyrrhonota .

Western Birds↗

USGS2011

Distribution and density of marine birds and mammals along the Kenai Fjords National Park coastline - March 2010

From March 21, 2010 to March 24, 2010, a winter marine bird and mammal skiff-based survey along the coast of Kenai Fjords National Park (KEFJ) was completed. This was the second winter survey completed for KEFJ since 2008. The primary objectives of the SWAN winter surveys are to characterize the species composition, density and distribution of the overwintering marine ducks prior to their migration to breeding grounds. Seasonal differences in species composition, distribution and density of other marine birds and mammals are also documented. The overall design calls for the sampling of the same transects during both the winter and summer surveys if safe and appropriate conditions allow. The 2010 survey took approximately four days to complete with a crew of six. The most common birds observed on the nearshore transects were the Barrow’s goldeneye (29.35/km2 , SE=9.24) and harlequin duck (29.30/km2 , SE=4.72). Harlequin ducks tended to be more evenly distributed along the coastline while Barrow’s goldeneye tended to be observed in less exposed areas along the coast and in larger groups. In contrast, the most abundant marine bird in KEFJ summer surveys is the Glaucous-winged gull, while Barrow’s goldeneye are nearly absent along the KEFJ coast. The most common marine mammal was the harbor seal (6.75/km2 , se=2.93) followed by the sea otter (3.59/km2 , se=0.90, adults and pups). Densities of harbor seals and sea otters in the summer were similar to the winter estimates.

Alaska↗

USGS2011

Use of large-scale, multi-species surveys to monitor gyrfalcon and ptarmigan populations

We evaluated the ability of three large-scale, multi-species surveys in the Arctic to provide information on abundance and habitat relationships of Gyrfalcons ( Falco rusticolus ) and ptarmigan. The Program for Regional and International Shorebird Monitoring (PRISM) has surveyed birds widely across the arctic regions of Canada and Alaska since 2001. The Arctic Coastal Plain survey has collected abundance information on the North Slope of Alaska using fixed-wing aircraft since 1992. The Northwest Territories-Nunavut Bird Checklist has collected presence-absence information from little-known locations in northern Canada since 1995. All three surveys provide extensive information on Willow Ptarmigan (Lagopus lagopus) and Rock Ptarmigan (L. muta). For example, they show that ptarmigan are most abundant in western Alaska, next most abundant in northern Alaska and northwest Canada, and least abundant in the Canadian Archipelago. PRISM surveys were less successful in detecting Gyrfalcons, and the Arctic Coastal Plain Survey is largely outside the Gyrfalcon's breeding range. The Checklist Survey, however, reflects the expansive Gyrfalcon range in Canada. We suggest that collaboration by Gyrfalcon and ptarmigan biologists with the organizers of large scale surveys like the ones we investigated provides an opportunity for obtaining useful information on these species and their environment across large areas.

Alaska, Northern Canada↗