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: 2892
Antipredator strategies in breeding Bristle-thighed Curlews
Each fall the world’s breeding population of Bristle-thighed Curlews (Numenius tahitiensis) arrives on the central Pacific wintering grounds following a migration that entails a non- stop flight of over 5000 kilometers. Sun-drenched, palm-shrouded atolls will be their home for the ensuing eight months. Even in the avian world, however, such apparent luxury is not without costs. For the Bristle-thi
Authors
Brian J. McCaffery, Robert E. Gill
Change-in-ratio methods for estimating population size
Change-in-ratio (CIR) methods can provide an effective, low cost approach for estimating the size of wildlife populations. They rely on being able to observe changes in proportions of population subclasses that result from the removal of a known number of individuals from the population. These methods were first introduced in the 1940’s to estimate the size of populations with 2 subclasses under t
Authors
Mark S. Udevitz, Kenneth H. Pollock
Reproductive implications of egg-size variation in Black Brant
We analyzed variation in egg size of Black Brant (Branta bernicla nigricans) in relation to clutch size, laying date, female age, year, and position in the laying sequence. A total of 3,478 eggs was measured over three years. Egg size increased with clutch size and female age, and decreased with laying date, year, and position in the laying sequence. We did not detect a negative phenotypic correla
Authors
Paul L. Flint, James S. Sedinger
Roosting behavior of premigratory Dunlins (Calidris alpina)
We studied roosting behavior of Dunlins (Calidris alpina) during late summer along the coast of the Yukon-Kuskokwim Delta, Alaska, in relation to tidal cycle, time of day, time of season, and occurrence of predators. Within Angyoyaravak Bay, peak populations of 70,000-100,000 Dunlins occur each year. The major diurnal roost sites were adjacent to intertidal feeding areas, provided an unobstructed
Authors
Colleen M. Handel, Robert E. Gill
Structural evolution of an arc-basin: The Gravina Belt in central southeastern Alaska
The upper Middle Jurassic-Lower Cretaceous Gravina belt lies along the eastern margin of the Alexander terrane in southeastern Alaska. This group of turbidites and mafic to intermediate volcanic rocks was deformed during mid to Late Cretaceous time during the closing of a basin of unknown size between the Alexander terrane on the west and the Stikine terrane to the east. Therefore structures of Gr
Authors
Peter J. Haeussler
Suppression of guinea pig ileum induced contractility by plasma albumin of hibernators
Previous studies suggest that hibernation may be regulated by internal opioids and that the putative “hibernation induction trigger” (HIT) may itself be an opioid. This study examined the effect of plasma albumin (known to bind HIT) on induced contractility of the guinea pig ileum muscle strip. Morphine (400 nM) depressed contractility and 100 nM naloxone restored it. Ten milligrams of lyophilized
Authors
David S. Bruce, Douglas L. Ambler, Timothy M. Henschel, Peter R. Oeltgen, Sita P. Nilekani, Steven C. Amstrup
Distribution, numbers, and habitat of Bristle-thighed Curlews (Numinous tahitiensis) on Rangiroa atoll
We assessed the numbers, distribution, and habitat of Bristle-tithed Curlews (Numinous tahitiensis) on Rangiroa Atoll, Tuamotu Archipelago, during a visit in April 1988. We estimated a total of 250-350 curlews on the atoll. These birds were seen only on the southern and western rims, where they were most common on (1) saltpans within clusters of small islets and (2) narrow channels between islets
Authors
Robert E. Gill, Roland L. Redmond
Threshold foraging behavior of baleen whales
We conducted hydroacoustic surveys for capelin Mallotus villosus in Witless Bay, Newfoundland, Canada, on 61 days during the summers of 1983 to 1985. On 32 of those days in whlch capelin surveys were conducted, we observed a total of 129 baleen whales - Including 93 humpback Megaptera novaeangliae, 31 minke Balaenoptera acutorostrata and 5 fin whales B. phvsalus. Although a few whales were observe
Authors
John F. Piatt, David A. Methven
Paleomagnetism and geochronology of 23 Ma gabbroic intrusions in the Keku Strait, Alaska, and implications for the Alexander Terrane
Samples of Tertiary gabbro from 24 sites in the Keku Strait, Alaska, help constrain the displacement history of the Alexander terrane. Step heating experiments on a plagioclase separate from these previously undated intrusions indicate a discordant 40Ar/39Ar age of 23.1 ± 1.7 Ma. The characteristic magnetization resides in magnetite, is easily isolated by thermal and alternating field demagnetizat
Authors
Peter J. Haeussler, Robert S. Coe, Paul R. Renne
Paleomagnetism of the Late Triassic Hound Island Volcanics: Revisited
The collision and accretion of the Alexander terrane profoundly influenced the geologic history of Alaska and western Canada; however, the terrane's displacement history is only poorly constrained by sparse paleomagnetic studies. We studied the paleomagnetism of the Hound Island Volcanics in order to evaluate the location of the Alexander terrane in Late Triassic time. We collected 618 samples at
Authors
Peter J. Haeussler, Robert S. Coe, T.C. Onstott
Intraspecific variation in egg shape among individual emperor geese
Within-clutch variability in shape of 1743 eggs from 301 nests of Emperor Geese (Chen canagicus) laid over a 5-yr period was measured. Individual females laid similar shaped eggs in successive years, and eggs among clutches within females could not be distinguished. Cluster analysis correctly identified 69.9% of 136 known conspecific parasitic eggs. Repeatability estimates of elongation (0.73), sp
Authors
Margaret R. Petersen
Breeding chronology of mottled ducks in a Texas coastal marsh
The relationship between breeding chronology of Mottled Ducks (Anas fulvigula fulvigula) and wetland conditions at San Bernard National Wildlife Refuge was examined over a 3-yr period. Median nest initiation dates varied by as much as 68 d among years. Initiation occurred earlier in 1985 and 1987 versus 1986 (P < 0.05). Nesting initiation was not associated with winter and spring temperatures, but
Authors
J. Barry Grand