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160 records · Page 9Linked to original sources
USGS1989

Louisiana's statewide beach cleanup

Litter along Lousiana's beaches has become a well-recognized problem. In September 1987, Louisiana's first statewide beach cleanup attracted about 3300 volunteers who filled 16,000 bags with trash collected along 15 beaches. An estimated 800,173 items were gathered. Forty percent of the items were made of plastic and 11% were of polystyrene. Of all the litter collected, 37% was beverage-related. Litter from the oil and gas, commercial fishing, and maritime shipping industries was found, as well as that left by recreational users. Although beach cleanups temporarily rid Louisiana beaches of litter, the real value of the effort is in public participation and education. Civic groups, school children, and individuals have benefited by increasing their awareness of the problems of trash disposal.

Conference Paper↗
USGS2012

History and progress of the North American Soil Geochemical Landscapes Project, 2001-2010

In 2007, the U.S. Geological Survey, the Geological Survey of Canada, and the Mexican Geological Survey initiated a low-density (1 site per 1600 km 2 , 13323 sites) geochemical and mineralogical survey of North American soils (North American Soil Geochemical Landscapes Project). Sampling and analytical protocols were developed at a series of workshops in 20032004 and pilot studies were conducted from 20042007. The ideal sampling protocol at each site includes a sample from 05 cm depth, a composite of the soil A horizon, and a sample from the soil C horizon. The <2-mm fraction of each sample is analyzed for Al, Ca, Fe, K, Mg, Na, S, Ti, Ag, Ba, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Ga, In, La, Li, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Sn, Sr, Te, Th, Tl, U, V, W, Y, and Zn by inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry following a near-total digestion in a mixture of HCl, HNO 3 , HClO 4 , and HF. Separate methods are used for As, Hg, Se, and total C on this same size fraction. The major mineralogical components are determined by a quantitative X-ray diffraction method. Sampling in the conterminous U.S. was completed in 2010 (c. 4800 sites) with chemical and mineralogical analysis currently underway. In Mexico, approximately 66% of the sampling (871 sites) had been done by the end of 2010 with completion expected in 2012. After completing sampling in the Maritime provinces and portions of other provinces (472 sites, 7.6% of the total), Canada withdrew from the project in 2010. Preliminary results for a swath from the central U.S. to Florida clearly show the effects of soil parent material and climate on the chemical and mineralogical composition of soils. A sample archive will be established and made available for future investigations.

Earth Science Frontiers↗
USGS1995

Seabirds in Alaska

About 100 million seabirds reside in marine waters of Alaska during some part of the year. Perhaps half this population is composed of 50 species of nonbreeding residents, visitors, and breeding species that use marine habitats only seasonally (Gould et al. 1982). Another 30 species include 40-60 million individuals that breed in Alaska and spend most of their lives in U.S. territorial waters (Sowls et al. 1978). Alaskan populations account for more than 95% of the breeding seabirds in the continental United States, and eight species nest nowhere else in North America (USFWS 1992). Seabird nest sites include rock ledges, open ground, underground burrows, and crevices in cliffs or talus. Seabirds take a variety of prey from the ocean, including krill, small fish, and squid. Suitable nest sites and oceanic prey are the most important factors controlling the natural distribution and abundance of seabirds. The impetus for seabird monitoring is based partly on public concern for the welfare of these birds, which are affected by a variety of human activities like oil pollution and commercial fishing. Equally important is the role seabirds serve as indicators of ecological change in the marine environment. Seabirds are long-lived and slow to mature, so parameters such as breeding success, diet, or survival rates often give earlier signals of changing environmental conditions that population size itself. Seabird survival data are of interest because they reflect conditions affecting seabirds in the nonbreeding season, when most annual mortality occurs. Techniques for monitoring seabird populations vary according to habitat types and the breeding behavior of individual species (Hatch and Hatch 1978, 1989; Byrd et al. 1983). An affordable monitoring program can include but a few of the 1,300 seabird colonies identified in Alaska, and since the mid-1970's, monitoring effotrts have emphasized a small selection of surface-feeding and diving species, primarily kittiwakes ( Rissa spp.) and murres ( Uria spp.). Little or no information on trends is available for other seabirds (Hatch 1993a). The existing monitoring program occurs largely on sites within the Alaska Maritime National Wildlife Refuge, which was established primarily for the conservation of marine birds. Data are collected by refuge staff, other state and federal agencies, private organizations, university faculty, and students.

Alaska↗
USGS2009

Movement and habitat use of sika and white-tailed deer on Assateague Island National Seashore, Maryland

This research project was conducted to describe habitat use of sika deer ( Cervus nippon ) and white-tailed deer ( Odocoileus virginianus ) and possibly attribute the effects of ungulate herbivory to specific deer species, if spatial separation in habitat use could be identified. Sturm (2007) conducted an exclosure study to document the effect of feral horse ( Equus caballus ) herbivory, deer herbivory, and horse and deer herbivory combined on plant communities. Sturm (2007) found that ungulate herbivory reduced plant species richness, evenness, and diversity in the maritime forest and affected species composition in all habitats studied. Sturm (2007) also found that herbivory on some species could be directly attributable to either horse or deer. However, the effects of sika and white-tailed deer herbivory could not be separated via an exclosure study design because of the difficulty of passively excluding one deer species but not the other. We captured white-tailed deer and sika deer in January–March of 2006 and 2007 throughout the Maryland portion of Assateague Island. Deer were fitted with radio-collars and their survival and locations monitored via ground telemetry. Up to four locations were acquired per deer each week during early (May–June) and late (August–September) growth periods for vegetation on the island. Also, we estimated deer locations during a dormant vegetation period (November– December 2006). We used these data to estimate survival and harvest rates, document movements, and model habitat use. We captured and fitted 50 deer with radio-collars over the course of the study. Of these 50 deer, 36 were sika and 14 were white-tailed deer. Of the 36 sika deer, 10 were harvested, three were likely killed by hunters but not recovered, and one died of natural causes while giving birth. Of the 14 white-tailed deer, three were harvested, one was illegally killed, and two were censored because of study-related mortality. Annual survival was 0.48 (95% CI = 0.16–0.82) for male white-tailed deer, 0.74 (95% CI = 0.44–0.91) for female white-tailed deer, 0.56 (95% CI = 0.35–0.75) for male sika deer, and 0.86 (95% CI = 0.70–0.94) for female sika deer. The harvest rate was 0.12 (95% CI = 0.04–0.27) for female sika deer, 0.44 (95% CI = 0.25–0.65) for male sika deer, 0.18 (95% CI = 0.05–0.51) for female white-tailed deer, and 0.38 (95% CI = 0.10–0.78) for male white-tailed deer. Annual survival rates for both species were similar to what has been observed in other populations. Unfortunately, small sample sizes for male white-tailed deer limited inferences about harvest and survival rates, but harvest rates of females for both species were similar to other published studies. Hunting was the primary cause of mortality, and outside the hunting season survival was 0.98–1.00 for all species and sexes. We found that the home range area of sika deer was much greater than the home range area of white-tailed deer, but failed to detect any difference between sexes or among seasons. Sika deer also made long-distance movements and left the Maryland portion of Assateague Island. No sika deer left Assateague island during our study, but we did document the dispersal of a male whitetailed deer to the mainland. In their native range, sika deer have been able to readily expand populations and occupy vacant habitat (Kaji et al. 2000; Kaji et al. 2004). The long distance movements we observed on Assateague Island, especially relative to white-tailed deer, may reflect the ability of this species to exploit food resources that may be limited in quality or quantity, or both. However, we did not collect data to assess use of food resources by sika deer and whether this may have influenced long distance movements. We found both species of deer were less likely to use a habitat the further it was located from cover, which was defined as tall shrub or forest vegetation. For every 10 m (32 ft) from cover each species of deer was 1.23–1.38 times less likely to use any given habitat. Patterns in use of vegetation classes were similar across species and seasons. Relative to forest habitat, both species avoided dune herbaceous, disturbed lands, sand, and water categories. Both species neither avoided nor preferred developed herbaceous, low shrub, marsh herbaceous, and tall shrub categories compared to the forest category. However, there were consistent differences between the two species. During spring, white-tailed deer were more likely than sika deer to use forested, tall shrub, disturbed herbaceous, and sand areas, but were less likely to use all other habitats. During summer, habitat use was similar between the two species except that white-tailed deer tended to use forested habitat more. During winter, white-tailed deer were less likely to use dune herbaceous, low shrub, and forested habitats than sika deer. Sturm (2007) identified differential browsing on plant species between horses and deer, but his experimental design did not permit detection of differential browsing between sika and whitetailed deer. Our study of habitat use did not provide information to identify plant species that may be differentially consumed by sika and white-tailed deer based on differences in habitat use. We envision two approaches to addressing the effects of deer browsing. One approach would be further research that identifies the food habits of both deer species at the plant species level. This would be similar to food habits research conducted by Keiper (1985) and others or could involve direct observation of food consumption by both species. However, both fecal analysis and direct observation would be time-consuming and not guaranteed to identify differences. If the goal of ungulate population management is to protect the island ecosystem, another approach involving manipulation of deer abundance and monitoring the response of plant species known to be preferentially consumed by deer would be a more direct method of assessing effects of deer herbivory (Sturm 2007). Moreover, such an approach is not predicated on detecting differences between deer species. Direct manipulation of deer abundance could be incorporated into an adaptive management program (Williams et al. 2007) and may provide greater benefits to the management of ASIS in the long term. Harvest management decisions for white-tailed deer and sika deer are made on an ongoing basis and by coupling these decisions with a vegetative monitoring program it may be possible to reduce or minimize adverse effects of ungulate herbivory. Furthermore, management of feral horses could be incorporated into the decision process.

Maryland, Virginia↗
USGS1998

An overview of San Francisco Bay PORTS

The Physical Oceanographic Real-Time System (PORTS) provides observations of tides, tidal currents, and meteorological conditions in real-time. The San Francisco Bay PORTS (SFPORTS) is a decision support system to facilitate safe and efficient maritime commerce. In addition to real-time observations, SFPORTS includes a nowcast numerical model forming a San Francisco Bay marine nowcast system. SFPORTS data and nowcast numerical model results are made available to users through the World Wide Web (WWW). A brief overview of SFPORTS is presented, from the data flow originated at instrument sensors to final results delivered to end users on the WWW. A user-friendly interface for SFPORTS has been designed and implemented. Appropriate field data analysis, nowcast procedures, design and generation of graphics for WWW display of field data and nowcast results are presented and discussed. Furthermore, SFPORTS is designed to support hazardous materials spill prevention and response, and to serve as resources to scientists studying the health of San Francisco Bay ecosystem. The success (or failure) of the SFPORTS to serve the intended user community is determined by the effectiveness of the user interface.

California↗
USGS2011

Northwestern forested mountains: Chapter 8

Th e Northwestern Forested Mountains are ecologically diverse and geographically widespread, encompassing the mountain ecosystems of central and northwestern North America (CEC 1997; Figure 2.2). Th e ecoregion description is adapted from CEC (1997). Geographically, they extend from the Rocky Mountains and the Sierra Nevada north through the Siskiyous, the east side of the Cascade Range, and then east of the Coast Ranges to interior Alaska. Climatically, the region is characterized by a transition from a moist, maritime climate in the northwest, to a continental and drier climate in the Rockies in the southeast. Orographically generated rainfall creates both rain shadows and wet belts, often in close proximity.

General Technical Report↗
USGS2005

Seabird, fish, marine mammal, and oceanography coordinated investigations (SMMOCI) in Sitka Sound, Alaska, July 2000

Surveys for seabirds and marine mammals were conducted in and near Sitka Sound, Alaska (Fig. 1) from the M/V Tiĝlax̂ during 12-16 July 2000 (Table 1, Fig. 1). The objective was to characterize the marine environment in the vicinity of St. Lazaria Island, one of ten seabird colonies monitored annually by the Alaska Maritime National Wildlife Refuge (See Dragoo et al. 2003). In addition to censusing seabirds and mammals encountered on line transects, local oceanography was characterized by measuring water temperature and salinity continuously at the sea surface, and by taking profiles of the water column on a series of CTD transects. The relative abundance of zooplankton and fish biomass was measured using a dual -frequency echosounder. Significant acoustic targets were sampled with a m id-water trawl net. Long-lines were se t twice to catch and characterize diets of large demersal fish species. Rosenthal et al. (1981 and 1982) studied the bottomfish component of the nearshore habitats in southeastern Alaska including the Sitka Sound area during the summers of 1980 and 1981, allowing comparisons of our findings to those from the earlier works. There are no previous surveys for seabirds or marine mammals in this area with which we can compare our surveys.

Alaska↗
USGS2003

Seabird, fisheries, marine mammal, and oceanographic investigations around Kasatochi, Koniuji, and Ulak Islands, August 1996 (SMMOCI 96-3)

Although islands in the Aleutians are known to support some of the highest densities of seabirds in the world, their remoteness has limited systematic research on the at-sea distribution of seabirds near these colonies. Kasatochi, Koniuji, and Ulak islands, in the central Aleutian Islands, together comprise one of nine ecological sites monitored once every 5 years on an annual rotation since 1996 by the Alaska Maritime National Wildlife Refuge (AMNWR). To supplement annual colony monitoring and examine seabird distribution away from colony sites, the AMNWR personnel in conjunction with U.S. Geological Survey (USGS) researchers, conducted a pelagic survey of the waters around these 3 islands in 1996. Previous research in this area has focused on the seabird colony sites located on Kasatochi, Koniuji, and Ulak islands. Although boat-based circumnavigations have been used to evaluate colony populations (Early et al. 1981; Bailey and Trapp 1986; Byrd and Williams 1994; Byrd 1995a, 1995b), wide ranging pelagic surveys to examine foraging patterns had not previously been conducted near the islands. The goal of this survey was to examine foraging patterns of the seabirds nesting in the study area and identify factors that may explain seabird distribution patterns.

Alaska↗
USGS2003

Seabird tissue archival and monitoring project: Egg collections and analytical results 1999-2002

In 1998, the U.S. Geological Survey Biological Resources Division (USGS-BRD), the U.S. Fish and Wildlife Service (USFWS) Alaska Maritime National Wildlife Refuge (AMNWR), and the National Institute of Standards and Technology (NIST) began the Seabird Tissue Archival and Monitoring Project (STAMP) to collect and cryogenically bank tissues from seabirds in Alaska for future retrospective analysis of anthropogenic contaminants. The approach of STAMP was similar to that of the Alaska Marine Mammal Tissue Archival Project (AMMTAP). AMMTAP was started in 1987 by NIST and the National Oceanic and Atmospheric Administration (NOAA) as part of the Outer Continental Shelf Environmental Assessment Program sponsored by the Minerals Management Service. Presently sponsored by the USGS-BRD, AMMTAP continues its work as part of a larger national program, the Marine Mammal Health and Stranding Response Program. AMMTAP developed carefully designed sampling and specimen banking protocols. Since 1987, AMMTAP has collected tissues from marine mammals taken in Alaska Native subsistence hunts and has cryogenically banked these tissues at the NIST National Biomonitoring Specimen Bank (NBSB). Through its own analytical work and working in partnership with other researchers both within and outside Alaska, AMMTAP has helped to develop a substantial database on contaminants in Alaska marine mammals. In contrast, data and information is limited on contaminants in Alaska seabirds, which are similar to marine mammals in that they feed near the top of the food chain and have the potential for accumulating anthropogenic contaminants. During its early planning stages, STAMP managers identified the seabird egg as the first tissue of choice for study by the project. There is a relatively long history of using bird eggs for environmental monitoring and for investigating the health status of bird populations. Since 1998, protocols for collecting and processing eggs, and cryogenically banking egg samples have been developed by STAMP (see York et al. 2001). Eggs are being collected on an annual basis for several species at nesting colonies throughout Alaska. Aliquots of these egg samples are being analyzed on a regular basis for persistent organic pollutants and mercury. Results of this work have been published in scientific journals (Christopher et al. 2002) and in conference proceedings (Kucklick et al. 2002; Vander Pol et al. 2002a, 2002b). The intent of this report is to provide an up-to-date description of STAMP. The report contains the most recent egg collection inventory, analytical data, preliminary interpretations based on these data, and a discussion of possible future directions of the project.

Report↗
USGS2004

Ecological overview of Kenai Fjords National Park

The major drivers of Kenai Fjords ecosystems are tectonics and climate. In this overview, we describe how these forces have contributed to the shaping of the lands and ecosystems of Kenai Fjords. Physically, the park is comprised of several distinct components, set within a broader ecophysical framework that includes the Kenai Peninsula and coastal marine waters and islands. Squeezed between the Gulf of Alaska and the Kenai Mountains, the coastal zone of the park is a narrow band of exposed headlands and deep fjords. The Harding Icefield caps the Kenai Mountains above the fjords with ice estimated to be 3,000 feet (1,000 m) thick (Figure 1). Although not included in the National Park Service jurisdiction, the park is ecologically linked to the offshore marine ecosystem, and the embedded offshore islands, most of which are part of the Alaska Maritime National Wildlife Refuge, managed by the U.S. Fish and Wildlife Service.

Alaska↗
USGS2003

USGS Alaska Tissue Archival Projects: An update on FY02 activities

The banking of environmental specimens under cryogenic conditions for future retrospective analysis has been recognized for many years as an important part of environmental monitoring programs. Since 1987, the Alaska Marine Mammal Tissue Archival Project (AMMTAP) has been collecting tissue samples from marine mammals for archival in the National Biomonitoring Specimen Bank (NBSB) at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, USA. The USGS, Alaska Biological Science Center (ABSC), the NOAA Fisheries, Office of Protected Resources (NMFS), and the NIST conduct this partnership project, which began under the Mineral Management Service (MMS) Outer Continental Shelf Environmental Assessment Program. MMS remains the primary client agency for the AMMTAP providing programmatic guidance and review. The purpose of the project is to collect tissue samples from Alaska marine mammals and to store these specimens under the best conditions so that they can be analyzed for environmental contaminants and other constituents. A substantial part of the sample collection is from Arctic species and, since most of the animals sampled are from Alaska Native subsistence harvests, the project relies on cooperation and collaboration with several Alaska Native organizations and local governmental agencies. Although a substantial amount of recent research has been conducted on contaminants in Alaskan marine mammals, few data exists on colonial seabirds nesting in Alaska. Like marine mammals, seabirds are an important group of upper trophic level marine organisms with a potential for accumulating lipophilic contaminants and are identified by MMS as species of interest for monitoring activities. More than 95% of the seabirds breeding in the continental United States nest at colonies in the Bering and Chukchi seas and Gulf of Alaska (see USFWS 1992). Realizing the value of colonial seabirds in environmental monitoring and the lack of recent data from Alaskan seabird colonies, the U.S. Fish and Wildlife Service Alaska Maritime National Wildlife Refuge (USFWS-AMNWR), the U.S. Geological Survey Biological Resources Division (USGS-BRD), and the National Institute of Standards and Technology (NIST) initiated the Seabird Tissue Archival and Monitoring Project (STAMP) in 1998. The project was designed as a 100-year-long program to monitor long-term trends in environmental quality by collecting eggs at nesting colonies using standardized protocols, banking the egg contents under conditions that ensure chemical stability during long-term (decadal) storage, and analyzing subsamples of the stored material to establish baseline levels for persistent bioaccumulative contaminants (e.g., chlorinated pesticides, PCBs, mercury).

Conference Paper↗
USGS2009

18. Arctostaphylos Adanson, Fam. Pl. 2: 165. 1763.

Arctostaphylos is richly diverse and taxonomically challenging. Unequivocal fossils appear as far back as the middle Miocene. Many pulses of diversification and decimation may have taken place in the genus since then; evidence suggests that there has been a rapid radiation in the last 1.5 million years. Some morphological features are not clearly differentiated among taxa and appear to be mosaically distributed. Multiple lines of evidence suggest that Arctostaphylos is a terminal branch within Arbutoideae. Arctous is treated here as a separate genus, as it is likely sister to Arctostaphylos . Only one species of Arctostaphylos, A. uva-ursi , is found outside of western North America, Mexico, and Guatemala. Taxa are concentrated within the California Floristic Province (southern Oregon to northern Baja California, Mexico) with the greatest diversity along the central California coast, where over half of the taxa are found. Along the immediate California coastline, most Arctostaphylos species are found within vegetation strongly influenced by summer fog, either within maritime chaparral, as a forest-edge species, or as part of a closed-cone conifer woodland and forest. Away from the coast, Arctostaphylos species are distributed to the desert edge in chaparral woodlands and forests.

Book chapter↗
USGS2009

IPANE: Could New England's Early Detection Network benefit eastern Canada?

The Invasive Plant Analysis of New England (IPANE: ipane.org) is a multifaceted approach to regional early detection of invasive plants. IPANE, was founded in 2001 to create a comprehensive six state New England regional partnership to: minimize the ecological damage caused by invasive plants; provide reliable and accessible educational material; maintain a network of professional and trained volunteers to gather information and to locate new incursions; provide a web-accessible database and maps of invasive and potentially invasive plants; conduct and encourage research on the biology and ecology of invasive plants; and, use program-generated data to develop predictive distribution models for the region. This program uses the synergy of all the components to create a regional early detection and rapid assessment network to curtail new invasions before they become widespread on the regional landscape. IPANE is a model for the United States Geological Survey National Early Detection Network Toolbox, a compendium of information developed for use by Network partners. In addition, an Early Detection Alert system has been developed to inform key federal and state agency staff, conservation organizations, and those with vegetation management responsibilities about new or potential invaders to the region. These include current and anticipated distribution, diagnostic characters, images, pertinent biological and control information, and key contacts. Most of the non-native species currently considered invasive by IPANE appear to be spreading into New England from the south or west. IPANE is strategically placed to act as an advanced warning system for the 5 provinces of Eastern and Maritime Canada. At the meeting held in Nova Scotia in September 2007, this idea was suggested to attendees from 4 of these 5 provinces and the Canadian government. By expanding its alert systems, IPANE could serve as a focal point for Early Detection information moving in any direction and tie Eastern Canada into the National Early Detection Network of the United States.

Conference Paper↗
USGS2020

Seabird synthesis

Overall, the status of seabirds was fair to good in the WGOA in 2020, with limited data available from Middleton Island, Cook Inlet, and the Kodiak Archipelago (Figure 63). Colony attendance remains low in some populations compared to historic levels, and some colonies were newly abandoned. However, when birds did arrive to breed, reproductive success generally appeared fair to good for fish-eating, surface-feeding birds and fish-eating, diving birds. There was spatial variability in colony attendance and reproductive success, with Middleton Island birds performing more strongly than Kodiak Island or Cook Inlet. Middleton Island populations from both these groups experienced their strongest breeding seasons since the marine heatwave began in 2014, suggesting an increase in the availability of small schooling fish in that region of WGOA. No large-scale mortality event was recorded based on monthly beach surveys in the WGOA. This year’s integrated approach to reporting seabird status is less comparable to previous Ecosystem Status Reports, as the Alaska Maritime National Wildlife Refuge’s seabird reproductive success time series were not updated, due to COVID-19 related survey cancellations.

Alaska↗
USGS2001

Biology and conservation of the common murre in California, Oregon, Washington, and British Columbia: Vol. 1, Natural history and population trends

Over the past 30 years, the common murre ( Uria aalge californica ) has been recognized as a prominent indicator of marine conservation issues in California, Oregon, Washington, and British Columbia, especially regarding oil pollution, certain fisheries, and human disturbance. To assist the effective management of the common murre and the marine environments in which they live, this summary of available information on the biology and regional status of the common murre has been sponsored by the U.S. Fish and Wildlife Service (Division of Migratory Bird Management). In Volume 1 (Chapter 1), the natural history of the common murre is summarized, drawing heavily on breeding studies from the South Farallon Islands, California, plus a host of detailed breeding studies from the North Atlantic Ocean. Population trends of the common murre are summarized in Volume 1 (Chapter 2), focusing on changes in whole-colony counts determined from aerial photographs between the late 1970s and 1995 in California, Oregon and Washington. Historical data and human impacts to murre colonies since the early nineteenth century are also summarized. Volume 2 will summarize population threats, conservation, and management. Information presented in Volume 1 has been obtained and recorded by a large number of researchers and natural historians over two centuries. From the 1960s to 1995, most work in California, Oregon, and Washington was sponsored by the U.S. Fish and Wildlife Service, Minerals Management Service, and California Department of Fish and Game. Important breeding biology studies were conducted at the South Farallon Islands (Farallon National Wildlife Refuge) by the Point Reyes Bird Observatory, in coordination with the U.S. Fish and Wildlife Service (San Francisco Bay National Wildlife Refuge). Colony surveys in California were conducted mainly by the U.S. Fish and Wildlife Service (San Francisco Bay National Wildlife Refuge), U.S. Geological Survey (Western Ecological Research Center, Dixon Field Station), Humboldt State University, and University of California (Santa Cruz). Colony surveys in Oregon and Washington were conducted mainly by the U.S. Fish and Wildlife Service (Oregon Coast National Wildlife Refuge and Washington Maritime National Wildlife Refuges). In British Columbia, most work from the 1960s to 1995 was sponsored and conducted by the Canadian Wildlife Service and Royal British Columbia Museum.

British Columbia, California, Oregon, Washington↗