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Page 4642, results 116026 - 116050

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Publication Extents

Not all publications have extents, not all extents are completely accurate
Agonistic asymmetries and the foraging ecology of Bald Eagles
Richard L. Knight, Susan Knight Skagen
1988, Ecology (69) 1188-1194
We investigated the effects of both asymmetries and differing food levels on contest outcomes of wintering Bald Eagles (Haliaeetus leucocephalus) feeding on chum salmon (Oncorhynchus keta) carcasses. Large eagles, regardless of age, were more successful in pirating than smaller eagles. Small pirating eagles were usually unsuccessful unless they were adults...
Tunnel-construction methods and foraging path of a fossorial herbivore, Geomys bursarius
Douglas C. Andersen
1988, Journal of Mammalogy (69) 565-582
The fossorial rodent Geomys bursarius excavates tunnels to find and gain access to belowground plant parts. This is a study of how the foraging path of this animal, as denoted by feeding-tunnel systems constructed within experimental gardens, reflects both adaptive behavior and constraints associated with the fossorial lifestyle. The principal...
Stochastic analysis of solute arrival time in heterogeneous porous media
Allen M. Shapiro, V.D. Cvetkovic
1988, Water Resources Research (24) 1711-1718
Longitudinal advective solute movement in heterogeneous porous media is investigated by considering the solute arrival time at a plane perpendicular to the mean fluid velocity. The moments of the solute arrival time are defined in terms of the stochastic properties of a statistically anisotropic hydraulic conductivity field. The flux‐averaged concentration...
Selenium teratogenesis in natural populations of aquatic birds in central California
David J. Hoffman, Harry M. Ohlendorf, Thomas W. Aldrich
1988, Archives of Environmental Contamination and Toxicology (17) 519-525
The frequency and types of malformations are described that were encountered during the spring of 1983 in a natural population of aquatic birds exposed to agricultural drainwater ponds and food items containing high concentrations of selenium in central California. A total of 347 nests of aquatic birds containing 1,681 eggs...
An exploration geochemical technique for the determination of preconcentrated organometallic halides by ICP-AES
J. M. Motooka
1988, Applied Spectroscopy (42) 1293-1296
An atomic absorption extraction technique which is widely used in geochemical exploration for the determination of Ag, As, Au, Bi, Cd, Cu, Mo, Pb, Sb, and Zn has been modified and adapted to a simultaneous inductively coupled plasma-atomic emission instrument. The experimental and operating parameters are described for the preconcentration...
Status of dugongs in waters around Palau
Galen B. Rathbun, Robert L. Brownell Jr., Katherine Ralls, John Engbring
1988, Marine Mammal Science (4) 265-270
The dugong, Dugong dugon, is widely distributed throughout the Indo-Pacific region in shallow tropical and subtropical waters (Nishiwaki and Marsh 1985).The International Union for Conservation of Nature and Natural Resources lists the species as vulnerable (Thornback and Jenkins 1982), as it is severely depleted or extinct in many parts of...
Duck nest success in the prairie pothole region
Albert T. Klett, Terry L. Shaffer, Douglas H. Johnson
1988, Journal of Wildlife Management (52) 431-440
We estimated nest success of mallard (Anas platyrhynchos), gadwall (A. strepera), blue-winged teal (A. discors), northern shoveler (A. clypeata), and northern pintail (A. acuta) for 5 regions in North Dakota, South Dakota, and Minnesota, for 1-3 periods between 1966 and 1984, and for 8 habitat classes. We obtained composite estimates...
A new Lower Carboniferous tetrapod locality in Iowa
J.R. Bolt, R.M. McKay, B.J. Witzke, M.P. McAdams
1988, Nature (333) 768-770
The earliest tetrapods known are from two or three Upper Devonian1–3 and some 20 Lower Carboniferous localities in Scotland4 and North America5–8. Most sites yield few and fragmentary specimens; well-preserved and even partially articulated material is exceedingly rare. This report discusses a middle Lower Carboniferous site rich in amphibian and fish...
Empirical estimates of body drag of large waterfowl and raptors
C.J. Pennycuick, H.H. Obrecht III, M.R. Fuller
1988, Journal of Experimental Biology (135) 253-264
Measurements of the body frontal area of some large living waterfowl (Anatidae) and raptors (Falconiformes) were found to vary with the two-thirds power of the body mass, with no distinction between the two groups. Wind tunnel measurements on frozen bodies gave drag coefficients ranging from 0·25 to 0·39, in the...
Sublethal landrin toxicity: Behavioral and physiological effects on captive vultures
D.L. Forthman-Quick, E. F. Hill
1988, Journal of Wildlife Management (52) 233-237
Use of conditioned taste aversion (CTA) has been proposed to reduce consumption of California condor (Gymnogyps californianus) eggs by ravens (Corvus corax). Although landrin has induced aversions in ravens and other birds, no data were available on behavioral and physiological effects of landrin on condors, non-target birds that might consume...
Wind tunnel experiments to assess the effect of back-mounted radio transmitters on bird body drag
H.H. Obrecht III, C.J. Pennycuick, M.R. Fuller
1988, Journal of Experimental Biology (135) 265-273
The aerodynamic drag of bird bodies was measured in a wind tunnel, with and without back-mounted dummy radio transmitters. Flight performance estimates indicate that the drag of a large transmitter can cause a substantial reduction of a migrant’s range, that is, the distance it can cover in non-stop flight. The...
The dissolution of quartz in dilute aqueous solutions of organic acids at 25°C
P.C. Bennett, M.E. Melcer, D. I. Siegel, J.P. Hassett
1988, Geochimica et Cosmochimica Acta (52) 1521-1530
The dissolution of quartz in dilute aqueous solutions of organic acids at 25° and standard pressure was investigated by the batch dissolution method. The bulk dissolution rate of quartz in 20 mmole/Kg citrate solutions at pH 7 was 8 to 10 times faster than that in pure water. After 1750...
Air pollution and wildlife toxicology: An overlooked problem
J.R. Newman, R. K. Schreiber
1988, Environmental Toxicology and Chemistry (7) 381-390
Since the 1880s, there have been repeated reports worldwide of toxic effects to wildlife from air pollution. Incidents in North America were recorded as early as the 1920s and as recently as last year. The effects have ranged from death and injury to increased incidence of infectious diseases, and they are...