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Publications

USGS research activities relevant to Alaska have yielded more than 9400 historical publications. This page features some of the most recent newsworthy research findings.

Filter Total Items: 3079

Ecology and conservation of North American sea ducks Ecology and conservation of North American sea ducks

The past decade has seen a huge increase in the interest and attention directed toward sea ducks, the Mergini tribe. This has been inspired, in large part, by the conservation concerns associated with numerical declines in several sea duck species and populations, as well as a growing appreciation for their interesting ecological attributes. Reflecting the considerable research recently...

Identifying a reliable blubber measurement site to assess body condition in a marine mammal with topographically variable blubber, the Pacific walrus Identifying a reliable blubber measurement site to assess body condition in a marine mammal with topographically variable blubber, the Pacific walrus

Pacific walruses may be unable to meet caloric requirements in the changing Arctic ecosystem, which could affect body condition and have population-level consequences. Body condition has historically been monitored by measuring blubber thickness over the xiphoid process (sternum). This may be an unreliable condition index because blubber at other sites along the body may be...
Authors
Shawn R. Noren, Mark S. Udevitz, Lisa Triggs, Jessa Paschke, Lisa Oland, Chadwick V. Jay

Phylogenetics, phylogeography and population genetics of North American sea ducks (tribe: Mergini) Phylogenetics, phylogeography and population genetics of North American sea ducks (tribe: Mergini)

Many environments occupied by North American sea ducks are remote and difficult to access, and as a result, detailed information about life history characteristics that drive population dynamics within and across species is limited. Nevertheless, progress on this front during the past several decades has benefited by the application of genetic technologies, and for several species, these
Authors
Sandra L. Talbot, Sarah A. Sonsthagen, John M. Pearce, Kim T. Scribner

Remigial molt of sea ducks Remigial molt of sea ducks

Molt is a dynamic process occurring throughout much of the year in waterfowl. The molt of flight feathers by waterfowl, especially sea ducks, however, occurs over a compressed period of time and in spcific areas used each year. We provide an overview of the flight feather molt of sea ducks. We focus on the need to molt and why, the timing and duration of flight feather mot, and the...
Authors
Margaret R. Petersen, Jean-Pierre L. Savard

Conclusions, synthesis, and future directions: understanding sources of population change Conclusions, synthesis, and future directions: understanding sources of population change

The material in this volume reflects the burgeoning interest in sea ducks, both as study species with compelling and unique ecological attributes and as taxa of conservation concern. In this review, we provide perspective on the current state of sea duck knowledge by highlighting key findings in the preceding chapters that are of particular value for understanding or influencing...
Authors
Daniel Esler, Paul L. Flint, Dirk V. Derksen, Jean-Pierre L. Savard, John M. Eadie

Population dynamics of sea ducks: using models to understand the causes, consequences, evolution, and management of variation in life history characteristics Population dynamics of sea ducks: using models to understand the causes, consequences, evolution, and management of variation in life history characteristics

In this chapter, I explore population dynamics of sea ducks by developing population models. In determining which life history characteristics had the greatest influence on future population dynamics, adult female survival consistently had the highest sensitivity and elasticity and this result was robust across a wide range of life history parameter values. Conversely, retrospective...
Authors
Paul L. Flint

Habitats of North American sea ducks. Habitats of North American sea ducks.

Breeding, molting, fall and spring staging, and wintering habitats of the sea duck tribe Mergini are described based on geographic locations and distribution in North America, geomorphology, vegetation and soil types, and fresh water and marine characteristics. The dynamics of habitats are discussed in light of natural and anthropogenic events that shape areas important to sea ducks...
Authors
Dirk V. Derksen, Margaret R. Petersen, Jean-Pierre L. Savard

Variation in migration strategies of North American sea ducks Variation in migration strategies of North American sea ducks

Migration exerts strong effects on population dynamics, so consideration of migration as a driver of population change is an important area of inquiry. Sea ducks (Mergini) exemplify the wide range in types of migration strategies, which become more variable with the addition of a third migration to distinct molting areas. We discuss the three migrations, summer, fall, and molt, and...
Authors
Margaret R. Petersen, Jean-Pierre L. Savard

Diet of yellow-billed loons (Gavia adamsii) in Arctic lakes during the nesting season inferred from fatty acid analysis Diet of yellow-billed loons (Gavia adamsii) in Arctic lakes during the nesting season inferred from fatty acid analysis

Understanding the dietary habits of yellow-billed loons (Gavia adamsii) can give important insights into their ecology, however, studying the diet of loons is difficult when direct observation or specimen collection is impractical. We investigate the diet of yellow-billed loons nesting on the Arctic Coastal Plain of Alaska using quantitative fatty acid signature analysis. Tissue analysis...
Authors
T B Haynes, Joel A. Schmutz, Jeffrey F. Bromaghin, S J Iverson, V. M. Padula, A E Rosenberger

Can polar bears use terrestrial foods to offset lost ice-based hunting opportunities? Can polar bears use terrestrial foods to offset lost ice-based hunting opportunities?

Increased land use by polar bears (Ursus maritimus) due to climate-change-induced reduction of their sea-ice habitat illustrates the impact of climate change on species distributions and the difficulty of conserving a large, highly specialized carnivore in the face of this global threat. Some authors have suggested that terrestrial food consumption by polar bears will help them withstand...
Authors
Karyn D. Rode, Charles T. Robbins, Lynne Nelson, Steven C. Amstrup

Prevalence and genetic diversity of haematozoa in South American waterfowl and evidence for intercontinental redistribution of parasites by migratory birds Prevalence and genetic diversity of haematozoa in South American waterfowl and evidence for intercontinental redistribution of parasites by migratory birds

To understand the role of migratory birds in the movement and transmission of haematozoa within and between continental regions, we examined 804 blood samples collected from eleven endemic species of South American waterfowl in Peru and Argentina for infection by Haemoproteus, Plasmodium, and/or Leucocytozono blood parasites. Infections were detected in 25 individuals of six species for...
Authors
Matthew M. Smith, Andrew M. Ramey

A real-time, quantitative PCR protocol for assessing the relative parasitemia of Leucocytozoon in waterfowl A real-time, quantitative PCR protocol for assessing the relative parasitemia of Leucocytozoon in waterfowl

Microscopic examination of blood smears can be effective at diagnosing and quantifying hematozoa infections. However, this method requires highly trained observers, is time consuming, and may be inaccurate for detection of infections at low levels of parasitemia. To develop a molecular methodology for identifying and quantifying Leucocytozoon parasite infection in wild waterfowl...
Authors
Matthew M. Smith, Joel A. Schmutz, Chloe Apelgren, Andrew M. Ramey
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