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Geology topics

R. G. Osborn

Publications and source records attributed to R. G. Osborn.

8 recordsLinked to original sources
USGS2008

Does the use of vaginal-implant transmitters affect neonate survival rate of white-tailed deer Odocoileus virginianus?

We compared survival of neonate white-tailed deer Odocoileus virginianus captured using vaginal-implant transmitters (VITs) and traditional ground searches to determine if capture method affects neonate survival. During winter 2003, 14 adult female radio-collared deer were fitted with VITs to aid in the spring capture of neonates; neonates were captured using VITs (N=14) and traditional ground searches (N=7). Of the VITs, seven (50%) resulted in the location of birth sites and the capture of 14 neonates. However, seven (50%) VITs were prematurely expelled prior to parturition. Predation accounted for seven neonate mortalities, and of these, five were neonates captured using VITs. During summer 2003, survival for neonates captured using VITs one, two, and three months post capture was 0.76 (SE=0.05; N=14), 0.64 (SE=0.07; N=11) and 0.64 (SE=0.08; N=9), respectively. Neonate survival one, two and three months post capture for neonates captured using ground searches was 0.71 (SE=0.11; N=7), 0.71 (SE=0.15; N=5) and 0.71 (SE=0.15; N=5), respectively. Although 71% of neonates that died were captured <24 hours after birth using VITs, survival did not differ between capture methods. Therefore, use of VITs to capture neonate white-tailed deer did not influence neonate survival. VITs enabled us to capture neonates in dense habitats which would have been difficult to locate using traditional ground searches.

Wildlife Biology↗
USGS2000

Bird mortality associated with wind turbines at the Buffalo Ridge wind resource area, Minnesota

Recent technological advances have made wind power a viable source of alternative energy production and the number of windplant facilities has increased in the United States. Construction was completed on a 73 turbine, 25 megawatt windplant on Buffalo Ridge near Lake Benton, Minnesota in Spring 1994. The number of birds killed at existing windplants in California caused concern about the potential impacts of the Buffalo Ridge facility on the avian community. From April 1994 through Dec. 1995 we searched the Buffalo Ridge windplant site for dead birds. Additionally, we evaluated search efficiency, predator scavenging rates and rate of carcass decomposition. During 20 mo of monitoring we found 12 dead birds. Collisions with wind turbines were suspected for 8 of the 12 birds. During observer efficiency trials searchers found 78.8% of carcasses. Scavengers removed 39.5% of carcasses during scavenging trials. All carcasses remained recognizable during 7 d decomposition trials. After correction for biases we estimated that approximately 36 ?? 12 birds (<1 dead bird per turbine) were killed at the Buffalo Ridge windplant in 1 y. Although windplants do not appear to be more detrimental to birds than other man-made structures, proper facility sitting is an important first consideration in order to avoid unnecessary fatalities.

Minnesota↗
USGS1998

Bird flight characteristics near wind turbines in Minnesota

During 1994–1995, we saw 70 species of birds on the Buffalo Ridge Wind Resource Area. In both years bird abundance peaked in spring. Red-winged blackbirds ( Agelaius phoeniceus ), mallards ( Anas platyrhynchos ), common grackles ( Quiscalus quiscula ), and barn swallows ( Hirundo rustica ) were the species most commonly seen. Most birds (82–84%) flew above or below the height range of wind turbine blades (22–55 m). The Buffalo Ridge Wind Resource Area poses little threat to resident or migrating birds at its current operating level.

Minnesota↗
USGS1991

QuickMAP

QuickMAP, a prototype desktop mapping system (DMS), uses easy to learn, simple to use windows, menus, and dialogues to provide support in natural resources decision-making.

Environmental Software↗
USGS1986

Energy budget and prey requirements of breeding lapland longspurs Calcarius lapponicus near Barrow Alaska, U.S.A.

Breeding Lapland longspurs, Calcarius lapponicus , near Barrow, Alaska, have relatively constant energy demands throughout the summer; the average estimated daily energy budgets (DEBs) were 132 and 118 kJ for the male and female. Thermoregulation accounted consistently for one-quarter to one-third of the total DEB. Flight in the male and incubation in the female were major components of the DEB early in the season, whereas cost of molt was a major component for both sexes near the end of the season. Our estimates of longspur DEB based on a time-activity approach were similar to those based on a cage existence model. Minor differences are explained by increased male territorial activity, by energy savings of the female during incubation, and by contraction of the molt for both sexes within the short summer season. Male and female longspurs were estimated to capture 3000 to 10,000 seeds and insects d -1 (3-20 items min -1 foraging) for self maintenance while in summer residence near Barrow. Each adult was estimated to capture an additional 3000 insects d -1 ( 6-7 insects min -1 foraging) during the peak energy requirements to raise five young. While raising young, the maximum required capture rate of prey per time foraging for each adult occurred during the nestling stage; young are just achieving independence, however, when food supply is at a maximum.

Alaska↗