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The feeding habits of the Snail Kite (Rostrhamus sociabilis) were observed intermittently from 1967-1980 in Florida, USA. Approximately 97% of all observed foraging bouts were over marshes having sparse emergent vegetation. The visually-hunting kite was unable to forage over floating mats of exotic water hyacinth (Eichhornia crassipes). Male kites had...

The breeding biology of the Snail Kite was studied in Florida from 1968-1977 and intermittently from 1978-1980. Breeding occurred every month, but not in the same year. Peak egg-laying occurred from February through April or generally about 8 1 d before the onset of the rainy season in mid- or...

Subsurface agricultural drainage waters from western San Joaquin Valley, California, were found to contain elevated concentrations of the element selenium in the form of selenate. In 1978, these drainage waters began to replace previous input to Kesterson Reservoir, a pond system within Kesterson National Wildlife Refuge; this substitution was completed...

Double-crested cormorants (Phalacrocorax auritus ) collected in the Houston Ship Channel, Texas, USA, in November shortly after their fall migration contained residues of several industrial, agricultural, and petroleum contaminants including polychlorinated styrenes (PCS's), polychlorinated biphenyls (PCB's), DDE, and petroleum hydrocarbons. PCS concentrations in over-wintering birds collected in late February were...

Mallard (Anas platyrhynchos) pairs (2-4) and broods (1-2) have occurred sporadically each year during recent (1977-86) waterfowl investigations in Maine. State-wide brood counts (1956-1986) for 36 wetlands in Maine depict an average increase of 1-3 mallard broods. Broods occurred mostly on man-made impoundments. Numbers of mallards captured during banding (as...

In May 1984, 332 mammals of 10 species were collected at Kesterson Reservoir (San Joaquin Valley, Merced Co., CA), which had received selenium-laden irrigation drainwater, and at the nearby Volta Wildlife Area, which had not. The study concentrated on the California vole (Microtus californicus); 88 were taken at Kesterson,...

Temporary ponds on the Atlantic Coastal Plain in maryland were characterized according to water chemistry, rain input, phytoplankton, zooplankton and use by the spotted salamander Ambystoma maculatum during March-October 1983-1984. Neither the number of egg masses per unit of pond surface (abundance) nor the survival of spotted salamander embryos was...

Litter was collected from eight sites at distances as far as 33 km from an Al reduction plant in western Tennessee. As a result of an accumulation of fine litter (<4.75 mm) the weight of the litter per unit area was abnormally high at the two...

Beginning the day after hatching, American kestrel (Falco sparverius) nestlings were orally dosed daily for 10 days with 5 μL/g of distilled water (controls), 10 mg/kg, 25 mg/kg, or 60 mg/kg of paraquat dichloride (1,1′-dimethyl-4,4′-bipyridinium dichloride) in distilled water. Forty-four percent of the nestlings receiving 60 mg/kg died after 4...

The Southern Blue Ridge Province, which encompasses parts of northern Georgia, eastern Tennessee, and western North Carolina, has been predicted to be sensitive to impacts from acidic deposition, owing to the chemical composition of the bedrock geology and soils. This study confirms the predicted potential sensitivity, quantifies the level of...

Using previously published atlas data for 122 mixed-species wading bird colonies on islands along the Atlantic coast (Maine to Florida, 1976-77), we examined relationships between population sizes of 11 species of egrets, herons, ibises, and wood storks (Mycteria americana) and nine habitat variables. On nautical charts, we measured four island...

Acidic deposition occurs over most of the United States and the deposition patterns and theoretical vulnerabilities of aquatic ecosystems to chemical changes can be delineated, but few data exist on concomitant biological effects. Hypothetical direct effects are limited primarily to toxicity of various heavy metals mobilized at reduced...

No abstract available....

Radio telemetry was used to follow the movements and habitat use of female American Black ducks (Anas rubripes) trapped at Brigantine Division. Edwin B. Forsythe NWR (BNW) during three field seasons (1983-1896). Use of the BNWR impoundments was strongly associated with open vs. closed hunting seasons and with presence...

Phytoplankton biomass (as carbon) was estimated from chlorophyll a concentrations (Chla) and a mean value for the ratio of phytoplankton carbon to chlorophyll a in San Francisco Bay. The ratio was determined as the slope of a Model II regression of POC' against (Chla), where POC' is total particulate organic carbon minus sediment-associated non-phytoplankton...

Large-scale groundwater pumpage and water-level decline data are used in a preliminary attempt to identify the hydraulic connection between several wells and Devils Hole, a small pond in Nye County, Nevada, U.S.A. Results indicate that despite the discontinuous nature of the local aquifers, many wells have good hydraulic connection with...

The maximum historic rainfall-runoff floods measured in the United States, the People's Republic of China and the world all plot close to a smooth curve of drainage area versus discharge. In the United States, the possibility that flood peaks were overestimated and the closeness of these peaks to the probable...

The slope-area method can be used to calculate peak flood discharges when current-meter measurements are not possible. This calculation depends on several quantities, such as water-surface fall, that are subject to large measurement errors. Other critical quantities, such as Manning's n, are not even amenable to direct measurement but can only...

It is usually advantageous to use information regarding historical floods, if available, to define the flood-frequency relation for a stream. Peak stages can sometimes be determined for outstanding floods that occurred many years ago before systematic gaging of streams began. In the United States, this information is usually not available...

The maximum rainfall-runoff floods measured by indirect methods in small basins (0.39-370 km2) in the conterminous United States are examined. This analysis identified twelve floods that were the largest ever measured. These floods all occurred in semiarid to arid areas. For eleven of the twelve largest rainfall-runoff floods measured in...

The groundwater system in southern Oahu, Hawaii consists of a thick, areally extensive freshwater lens overlying a zone of transition to a thick saltwater body. This system is analyzed in cross section with a variable-density groundwater flow and solute transport model on a regional scale. The simulation is difficult, because...

This report summarizes data on the distribution and abundance of submersed aquatic vegetation collected in the tidal Potomac River and Estuary during 1986. Plant species were identified and dry weight determined for selected sites sampled in spring and fall. The percentage of each plant species was determined in areas of...