Evolutionary and behavioral ecology, waterfowl and wetlands, reproduction and energetics.
Professional Experience
1988 - Present Research Wildlife Biologist, USGS, Alaska Science Center, Anchorage, Alaska
1985 - 1988 Research Associate, Alaska Cooperative Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska (stationed in Anchorage, AK)
Education and Certifications
Ph.D. 1992 University of California Davis, Davis, CA Ecology
M.S. 1979 University of California Davis, Davis, CA Ecology
B.S. 1976 University of California Davis, Davis, CA Wildlife and Fisheries Biology
Affiliations and Memberships*
American Association for the Advancement of Science
American Ornithologists Union
American Society of Naturalists
Animal Behavior Society
Cooper Ornithological Society
The Wildlife Society
The Wildfowl Trust
American Society of Field Ornithologists
International Society of Behavioral Ecology
Science and Products
Swan Research
Satellite Tracking of Birds in Alaska Points to Distant Sources of Lead and Mercury Exposure
Body condition of wintering Pacific greater white-fronted geese
Exploring overlap of feather molting and migration in Tundra Swans using δ2H analysis
Conservation status of the world’s swan populations, Cygnus sp. and Coscoroba sp.: a review of current trends and gaps in knowledge
Identification of single nucleotide polymorphisms for use in a genetic stock identification system for greater white-fronted goose (Anser albifrons) subspecies wintering in California
Current trends and future directions in swan research: Insights from the 6th International Swan Symposium
Shorebirds adjust spring arrival schedules with variable environmental conditions: Four decades of assessment on the Yukon–Kuskokwim Delta, Alaska
Flyway structure in the circumpolar greater white‐fronted goose
Variation in age ratio of midcontinent greater white-fronted geese during fall migration
Genetic structure among greater white-fronted goose populations of the Pacific Flyway
Chewing lice of swan geese (Anser cygnoides): New host-parasite associations
Low survival rates of Swan Geese (Anser cygnoides) estimated from neck-collar resighting and telemetry
Demographic outcomes of diverse migration strategies assessed in a metapopulation of tundra swans
Tracking Data for Greater White-fronted Geese (Anser albifrons)
Tracking Data for Emperor Geese (Anser canagicus)
Stable Isotope Data from Tundra Swan (Cygnus columbianus) Feathers, Alaska, 2008 and 2010
Tracking Data for Tundra Swan (Cygnus columbianus)
Development of Single Nucleotide Polymorphisms (SNPs) in Greater-White Fronted Geese (Anser albifrons) for genetic stock identification on wintering grounds, 2019
Science and Products
- Science
Swan Research
USGS research on swans in Alaska has focused on pathogens, contaminants, and demographic rates in each of the different breeding areas of Alaska. The vastly different migration patterns of swans in Alaska means that there are multiple factors on the wintering grounds and during migration that may influence population size and trends.Satellite Tracking of Birds in Alaska Points to Distant Sources of Lead and Mercury Exposure
U.S. Geological Survey (USGS) scientists measured lead in blood from tundra swans that nest in Alaska and then followed the migration of these birds using satellite telemetry. Levels of lead in blood were higher in adults than young swans,suggesting exposure to lead occurs on wintering areas and/or during migration, rather than on the summer breeding grounds in Alaska. The lowest blood levels were... - Publications
Filter Total Items: 63
Body condition of wintering Pacific greater white-fronted geese
Extreme changes to key waterfowl habitats in the Klamath Basin (KB) on the Oregon–California border and the Sacramento Valley (SV) in California, USA, have occurred since 1980. The spatial distribution of Pacific greater white‐fronted geese (Anser albifrons sponsa; geese) has likewise changed among these areas and population size has grown from 79,000 to >600,000 geese during the same period. To aExploring overlap of feather molting and migration in Tundra Swans using δ2H analysis
Determining the processes that shape the relative timing of energetically-costly events in the annual cycle of migrating birds is important to our understanding of avian phenology and ecology. We paired satellite tracking and hydrogen stable isotope analysis (δ2H) to examine the relative timing of two such events – migration and feather molting – in tundra swans from four breeding areas in Alaska,Conservation status of the world’s swan populations, Cygnus sp. and Coscoroba sp.: a review of current trends and gaps in knowledge
Recent estimates of the world’s swan Cygnus sp. populations indicate that there are currently between 1.5–1.6 million birds in 8 species, including the Coscoroba Swan Coscoroba coscoroba as an honorary swan. Monitoring programmes in Europe and North America indicate that most populations increased following the introduction of national and international legislation to protect the species during thIdentification of single nucleotide polymorphisms for use in a genetic stock identification system for greater white-fronted goose (Anser albifrons) subspecies wintering in California
California provides wintering habitat for most greater white-fronted geese (Anser albifrons [GWFG]) in the Pacific Flyway and this population has rapidly increased since the 1980s. Increased harvest of GWFG wintering in California may prevent agricultural depredation while providing increased hunting opportunities. However, changes in harvest levels are unlikely to be uniform across the species beCurrent trends and future directions in swan research: Insights from the 6th International Swan Symposium
Given their popularity with researchers and public alike, together with their welldocumented importance in aquatic and terrestrial ecosystems, fundamental and applied research on swans continues to develop in the 21st century. The 6th International Swan Symposium (6th ISS), was held at the Estonian University of Life Sciences in Tartu, Estonia, in October 2018. The symposium brought together 101 dShorebirds adjust spring arrival schedules with variable environmental conditions: Four decades of assessment on the Yukon–Kuskokwim Delta, Alaska
Arctic summers are brief, and there has been strong selection for migratory birds to arrive in Arctic nesting areas as early as possible to time breeding with peak food availability and complete reproduction. The timing of emergence of nesting habitat in spring is, however, extremely variable in the Arctic, and few long-term studies have examined the ability of avian migrants to track spring condiFlyway structure in the circumpolar greater white‐fronted goose
Dispersal and migratory behavior are influential factors in determining how genetic diversity is distributed across the landscape. In migratory species, genetic structure can be promoted via several mechanisms including fidelity to distinct migratory routes. Particularly within North America, waterfowl management units have been delineated according to distinct longitudinal migratory flyways suppoVariation in age ratio of midcontinent greater white-fronted geese during fall migration
Annual productivity is an important parameter for the management of waterfowl populations. Fall age ratio (juveniles:total birds) is an index of productivity of the preceding breeding season. However, differences in the timing of migration between family groups and nonbreeding birds may bias age-ratio estimates. We examined temporal variation in age ratios of midcontinent greater white-fronted geeGenetic structure among greater white-fronted goose populations of the Pacific Flyway
An understanding of the genetic structure of populations in the wild is essential for long-term conservation and stewardship in the face of environmental change. Knowledge of the present-day distribution of genetic lineages (phylogeography) of a species is especially important for organisms that are exploited or utilize habitats that may be jeopardized by human intervention, including climate chanChewing lice of swan geese (Anser cygnoides): New host-parasite associations
Chewing lice (Phthiraptera) that parasitize the globally threatened swan goose Anser cygnoides have been long recognized since the early 19th century, but those records were probably biased towards sampling of captive or domestic geese due to the small population size and limited distribution of its wild hosts. To better understand the lice species parasitizing swan geese that are endemic to EastLow survival rates of Swan Geese (Anser cygnoides) estimated from neck-collar resighting and telemetry
Waterbird survival rates are a key component of demographic modeling used for effective conservation of long-lived threatened species. The Swan Goose (Anser cygnoides) is globally threatened and the most vulnerable goose species endemic to East Asia due to its small and rapidly declining population. To address a current knowledge gap in demographic parameters of the Swan Goose, available datasetsDemographic outcomes of diverse migration strategies assessed in a metapopulation of tundra swans
Background Migration is a prominent aspect of the life history of many avian species, but the demographic consequences of variable migration strategies have only infrequently been investigated, and rarely when using modern technological and analytical methods for assessing survival, movement patterns, and long-term productivity in the context of life history theory. We monitored the fates of 50 sa - News
- Data
Tracking Data for Greater White-fronted Geese (Anser albifrons)
This metadata document describes VHF tracking data for Greater White-fronted Geese (Anser albifrons) that were marked annually from 1987 to 1991 in Alaska and the Klamath Basin (Oregon and California) and subsequently tracked through the Pacific Flyway (primarily in Alaska, California, and Mexico). Only tracking data for geese marked or located, at least once, in Alaska are included in this data pTracking Data for Emperor Geese (Anser canagicus)
This metadata document describes the data contained in the "rawData" folder of this data package. This data package contains all data collected by the Argos System from 53 satellite transmitters attached to Emperor geese on their breeding range in western Alaska, 1999-2003. Five data files are included in the "rawData" folder of this data package. Two data files (with identical content) contain thStable Isotope Data from Tundra Swan (Cygnus columbianus) Feathers, Alaska, 2008 and 2010
These data are in a single table that provides date and location information of Tundra Swans (Cygnus columbianus) that were sampled in Alaska for feathers that were subsequently used in a stable isotope analysis. Results of deuterium, nitrogen, and carbon stable isotope analysis of feathers are provided.Tracking Data for Tundra Swan (Cygnus columbianus)
This metadata document describes the data contained in the "rawData" folder of this data package. This data package contains all data collected by the Argos System from 50 satellite transmitters attached to Tundra Swans on their breeding range in arctic and western Alaska, 2008. Five data files are included in the "rawData" folder of this data package. Two data files (with identical content) contaDevelopment of Single Nucleotide Polymorphisms (SNPs) in Greater-White Fronted Geese (Anser albifrons) for genetic stock identification on wintering grounds, 2019
This data set contains a description of 3 mitochondrial DNA and 93 nuclear DNA Single Nucleotide Polymorphism (SNP) loci and sequence information developed through double digest restriction-site associated DNA sequencing (ddRADseq) techniques for Greater White-Fronted Goose (Anser albifrons) that winter in California. - Multimedia
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government