Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “The Journal of Wildlife Management”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
USGS1994

Retention of web tags and plasticine-filled leg bands applied to day-old ducklings

A new plasticine-filled leg band was developed for use in banding dayold ducklings. These bands permit inference about early survival that is not possible from banding of older young in standard operations. Two double-marking experiments with web tags and the new leg bands indicated a high retention rate for the leg bands. In contrast, several web tags were lost, permitting an analysis directed at sources of variation in web tag retention rates. We found retention rates of web tags to be higher for diving ducks ( Aythya ) than for dabbling ducks ( Anas ), and higher for tags placed the web interior than for those applied to the web edge. However, we recommend that the new plasticine-filled leg bands be used in place of web tags because of their higher retention rates and presumably greater visibility to hunters. We believe they offer great potential for new studies of duckling survival and distribution.

Engure Marsh↗
USGS1994

Survival of radio-marked mallard ducklings in northeastern California

Estimates of duckling survival are necessary to accurately assess recruitment of mallards ( Anas platyrhynchos ), yet few reliable estimates exist. During 1988-90, we estimated survival rates for 127 radio-marked mallard ducklings from 64 broods on Lower Klamath National Wildlife Refuge, California. In 1988, we restricted the survival estimate to the first 10 days post-hatch ( S = 0.18, SE = 0.07). Survival from hatching to 50 days was 0.37 (SE = 0.09) in 1989 and 0.34 (SE = 0.07) in 1990. Total brood loss differed among years ( P < 0.05); 81.2% in 1988 ( n = 16), 36.8% in 1989 ( n = 19), and 37.5% in 1990 ( n = 24). Ninety-three percent of mortality occurred during the first 10 days of life. We detected no differences in the proportion of radio-marked ducklings fledged from early-hatched versus late-hatched nests ( P = 0.74). During 1989-90, 16 females appeared to lose their entire brood; however, 3 radio-marked ducklings from 2 of these broods were fledged by other brood hens. Of 29 radio-marked ducklings that reached 44 days of life, 6 (20.7%) joined other broods. Habitat enhancement is the key to improving duckling survival because the large number of predator species that consume ducklings makes predator control difficult.

California↗
USGS1994

Dioxins and furans linked to reproductive impairment in wood ducks

A wetland in central Arkansas was contaminated with polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans and because the area was a major waterfowl habitat, we studied the effects of the contamination on nesting wood ducks ( Aix sponsa ) during 1988-90. Residues in wood duck eggs, based on toxicity equivalency factors (TEFs) for combined compounds, ranged from 0.2 to 611 parts per trillion (ppt) wet mass (70% were the toxic isomer 2,3,7,8-tetrachlorodibenzo-p-dioxin (tetraCDD)) and were 50 times higher in eggs from near the point source than from an uncontaminated reference site 111 km away. Nest success, hatching success, and duckling production were suppressed ( P < 0.05) at nesting sites 9 and 17 km downstream, as was hatching success 58 km downstream. Egg TEFs were inversely correlated ( P < 0.001) with productivity in corresponding nests. In addition, teratogenic effects occurred in ducklings at the more contaminated nesting site nearest the point source. The threshold range of toxicity (based on TEFs) where reduced productivity was evident in wood ducks was gt 20-50 ppt. Wood ducks were sensitive to dioxin and furan contamination, and we recommend it as an indicator species for monitoring biological impacts from these contaminants.

Arkansas↗
USGS1994

Herbivory on shoalgrass by wintering redheads in Texas

An estimated 80% of redheads ( Aythya americana ) winter on the Laguna Madre of south Texas and Mexico and feed almost exclusively on shoalgrass ( Halodule wrightii ) rhizomes. Shoalgrass abundance has decreased by 60% over the past 30 years, and because the effects of shoalgrass loss on wintering redheads are unknown, we initiated a study to define habitat selection criteria and document the effect of wintering redheads on shoalgrass in the lower Laguna Madre, Texas. Redheads consumed an average of 75% of shoalgrass rhizome biomass at collection sites each winter. When rhizome biomass was grazed to a mean biomass of ltoreq 0.18 g dry mass/core (approximately 10 g dry mass/ml), shoalgrass did not recover to its previous level the following growing season. Thirty-three percent of the sites (10) were grazed below 0.18 g dry mass/core during both years of the study, while 64% (19) were grazed below 0.18 g during 1 or the other of the 2 winters. Ramet number was positively correlated ( P < 0.001, r 2 = 0.54) with rhizome biomass; however, this relationship was influenced by grazing intensity. Heavy grazing reduced the amount of rhizome attached to each ramet compared with ungrazed ramets. Grazing had no effect on root biomass ( P = 0.388), rhizome moisture content ( P = 0.553), or soil magnesium, phosphorous, and potassium ( P = 0.102, 0.499, 0.162, respectively). Redhead presence increased ( P = 0.042) soil nitrogen levels. Foraging areas selected by redheads within the lower Laguna Madre had lower ( P = 0.026) salinities (24 ppt) than areas not selected (35 ppt). Redheads did not select foraging areas in relation to crude protein levels in rhizomes. Shoalgrass habitat in the Laguna Madre should be protected from further losses and enhanced where possible.

Texas↗
USGS1994

Survival rates of American woodcock wintering along the Atlantic coast

Because American woodcock ( Scolopax minor ) populations have been declining, we attached radio transmitters to woodcock at coastal plain sites to determine if survival during winter was involved in the decline. Sites were in Georgia (1982-84, 1989-92), South Carolina (1988-89), and Virginia (1991-92). Survival rates were not different between age or sex classes. Survival rates differed ( P = 0.003) among years. Daily survival rates were lowest ( P = 0.030, S = 0.987) during 1982-83 in Georgia and highest ( P = 0.004, S = 0.999) during 1990-91 in Georgia than in the other years and locations combined ( S = 0.996). We attributed all mortality to raptors and mammals. Compared with other periods of the year, winter was a time of low survival for woodcock. Lower survival rates were possibly a cause of population decline.

Georgia, South Carolina, Virginia↗
USGS1994

Essential amino acids in northern bobwhite foods

Frequent population declines, high dietary requirements for protein, and the low quality of proteins in agricultural grains led us to hypothesize that essential amino acid (EAA) deficiencies were common in northern bobwhite (Colinus virginianus) foods. We analyzed amino acid concentrations of 21 northern bobwhite foods and compared them with dietary requirements to derive values that reflected the foods' ability to meet daily bobwhite requirements of 10 EEAs. Despite adequate concentrations of crude protein, deficiencies of EAAs were detected in seeds of all species analyzed. Legumes offered the best mix of EAA, and grasses the poorest. Deficiencies of EEAs relative to maintenance requirements of adults ranged from 13% in legumes to 98% in grasses. About a third of the total nitrogen pool was composed of nonprotein nitrogen with values ranging from 25% for queensdelight stillingia (Stillingia sylvatica) to 44% for redroot amaranth (Amaranthus retroflexus). Computed biological values (ratio of EEA concentrations in seed protein to respective amounts in whole egg protein) ranged from 69 (netleaf hackberry [Celtis reticulata]) to 93 (erect dayflower [Commelina erecta] and woolly croton [Croton capitatus]). Amino acid profiles indicate forage quality better than crude protein estimates.

Journal of Wildlife Management↗
USGS1989

DDE, selenium, mercury, and white-faced ibis reproduction at Carson Lake, Nevada

We studied organochlorine, mercury (Hg), and selenium (Se) contamination in white-faced ibis ( Plegadis chihi ) nesting at Carson Lake, Nevada, in 1985 and 1986. Dichloro diphenyl dichloroethylene (DDE) was related to fewer young produced/nesting attempt (P = 0.0001), fewer young produced/successful nest (P = 0.0075), and eggshell thinning (P = 0.0001). As DDE in eggs increased to >4 ppm (wet wt), and especially > 8 ppm, productivity decreased significantly (P < 0.05) and the incidence of cracked eggs increased. Assuming that 4 ppm DDE is the critical residue level, 40% of the nesting population in 1985 and 1986 was adversely impacted by DDE, with a net loss of 20% of the population's expected production (to about 10 days old). Most eggs containing exceptionally high DDE levels (8-29 ppm) also had substantial amounts of dichloro diphenyl trichloroethane (DDT), which implies recently-used DDT as the source. No evidence of breeding ground DDE-DDT contamination was found. The white-faced ibis winter in Mexico, and mostly in the interior agricultural region. Concentrations of DDE-DDT in ibis eggs, unlike most other wading bird species from the Great Basin, did not decline during the last decade. Other organochlorine contaminants were generally low and detected in 533% of the eggs. Selenium and Hg were accumulated by ibis on the Nevada breeding grounds, but concentrations in eggs did not reach levels sufficient to impact the production of 7-10 day old young. Potential Se and especially Hg accumulation during the remainder of the summer was high, but actual effects on growing young and adults remain unknown.

Nevada↗
USGS1989

Survival and movements of molting male black ducks in Labrador

We marked 26 flightless male American black ducks with transmitters during the post-nuptial molt in northern Labrabor to determine survival and movements. Twelve ducks remained in the watershed where marked and 11 ducks moved to different watersheds. The period survival rate (PSR) for these flightless males was 0.89 using the Kaplan-Meier estimator. Only 2 ducks were killed by predators. Death of these 2 ducks might have been influenced by our disturbance, thus we considered the PSR minimal.

Journal of Wildlife Management↗
USGS1989

Effects of organophosphorus insecticides on sage grouse in southeastern Idaho

Die-offs of sage grouse ( Centrocercus urophasianus ) were verified in southeastern Idaho in 1981. We captured 82 apparently healthy grouse to quantify the effects of organophosphorus insecticides (OP's) and other pesticides on sage grouse in sagebrush ( Artemisia spp.) bordering agricultural lands in July 1985 and 1986. Grouse were fitted with radio collars and tracked through part of each summer. At least 18% of 82 radio-tagged grouse in 1985-86 subsequently occupied fields at the time they were sprayed with OP insecticides dimethoate or methamidophos. Cholinesterase (ChE) assays of brains and residue analysis of crop contents indicated that 5 and 16% of the marked sample died from OP's in 1985 and 1986, respectively. Approximately 200 sage grouse were present in a block of alfalfa sprayed with dimethoate; 63 of these were later found dead and ChE activity in 43 brains suitable for assay were depressed >50%. Maximum residues in crop contents of dead grouse were 18 μg/g methamidophos and 30 μg/g dimethoate. Intoxicated or dead grouse were observed in or near 6 fields sprayed with dimethoate or methamidophos in 1985-86. Twenty of 31 intoxicated grouse radiotagged after being found in dimethoate-sprayed (1986) alfalfa died. Our study indicates that certain pesticides have the potential for adversely affecting grouse populations.

Idaho↗
USGS1990

Effects of visiting black brant nests on egg and nest survival

I used 2 methods to evaluate the effect of visiting black brant (Branta bernicla nigricans) nests on survival of whole nests and eggs in a single colony on the Yukon-Kuskokwim Delta, Alaska. The first technique regressed survival of nests or eggs during a time interval against interval length. Departure of the y-intercept from 1.0 estimated the short-term effect of the visit at the beginning of the interval. The y-intercepts (±95% CI) for whole nests and eggs during the egg laying period were 1.11 ± 0.31 and 1.06 ± 0.31, respectively. During incubation the same 2 parameters were 0.66 ± 0.31 and 0.66 ± 0.33. The regression method was, thus, imprecise and failed to discriminate among widely varying potential impacts of visitors. The second method involved visiting nests and then immediately revisiting them after pairs had returned to their territories. This method estimated loss of eggs as a result of displacement of territorial pairs during the first visit. Only 1 of 50 eggs was lost (n = 27 nests) as a result of visits during egg laying, whereas no eggs were lost (n = 225 eggs and 55 nests) owing to visits during the incubation period. I conclude that the regression approach is an imprecise tool for estimating visitor impact, but results from both methods indicate little effect of nest visitation under conditions existing on the colony I studied.

Alaska↗
USGS1990

Recent trends in counts of migrant hawks from northeastern North America

Using simple regression, pooled-sites route-regression, and nonparametric rank-trend analyses, we evaluated trends in counts of hawks migrating past 6 eastern hawk lookouts from 1972 to 1987. The indexing variable was the total count for a season. Bald eagle ( Haliaeetus leucocephalus ), peregrine falcon ( Falco peregrinus ), merlin ( F. columbarius ), osprey ( Pandion haliaetus ), and Cooper's hawk ( Accipiter cooperii ) counts increased using route-regression and nonparametric methods (P < 0.05). Northern harrier ( Circus cyaneus ) counts increased based on the nonparametric method (P < 0.01) but not the route-regression method (P > 0.10). We found no consistent trends (P > 0.10) in counts of sharp-shinned hawks ( A. striatus ), northern goshawks ( A. gentilis ) red-shouldered hawks ( Buteo lineatus) , red-tailed hawks ( B. jamaicensis ), rough-legged hawsk ( B. lagopus ), and American kestrels ( F. sparverius ). Broad-winged hawk ( B. platypterus ) counts declined (P < 0.05) based on the route-regression method. Empirical comparisons of our results with those for well-studied species such as the peregrine falcon, bald eagle, and osprey indicated agreement with nesting surveys. We suggest that counts of migrant hawks are a useful and economical method for detecting long-term trends in species across regions, particularly for species that otherwise cannot be easily surveyed.

Michigan, Minnesota, New Jersey, New York, Pennsyl↗
USGS1990

Winter use of douglas-fir forests by Blue Grouse in Colorado

We studied winter use of Douglas-fir ( Pseudotsuga menziesii ) forests by blue grouse ( Dendragapus obscurus ) from 1981 to 1983 at 2 study areas in northcentral Colorado. Comparisons of used and available stands indicated grouse were concentrated spatially, but there were no consistent differences related to basal area of tree species, conifer stem densities, and topography that were common to both areas. Blue grouse used dense (2,000 stems/ha) second growth (40-75 yr old), open to dense (200-1,900 stems/ha) mature (100-200 yr old), and open (<100 stems/ha) old-growth (200-600 yr old) stands. Stands used were composed of Douglas-fir alone or in association with subalpine fir ( Abies lasiocarpa ), Engelmann spruce ( Picea engelmannii ), lodgepole pine ( Pinus contorta ), limber pine ( P. flexilis ), Rocky Mountain juniper ( Juniperus scopulorum ), and quaking aspen ( Populus tremuloides ). Grouse used stands on mesic northern and eastern aspects, on xeric southern and western aspects, at elevations of 2,530-2,960 m, and on slopes of 1-45°. Preferential use (P < 0.05) of Douglas-fir trees occurred within stands that had an abundance of limber pine (use = availability) and subalpine fir (use < availability). Large Douglas-fir (20-90 cm dbh) were preferred (P < 0.05) within stands that had an abundance of smaller (≤15 cm dbh) trees. Both sexes used similar trees.

Colorado↗
USGS1990

Error in telemetry studies: Effects of animal movement on triangulation

We used Monte Carlo simulations to investigate the effects of animal movement on error of estimated animal locations derived from radio-telemetry triangulation of sequentially obtained bearings. Simulated movements of 0-534 m resulted in up to 10-fold increases in average location error but <10% decreases in location precision when observer-to-animal distances were <1,000 m. Location error and precision were minimally affected by censorship of poor locations with Chi-square goodness-of-fit tests. Location error caused by animal movement can only be eliminated by taking simultaneous bearings.

Journal of Wildlife Management↗
USGS1989

Body weight and composition dynamics of fall migrating canvasbacks

We studied body weights and composition of canvasbacks (Aythya valisineria) during fall migration 1975-77 on stopover sites along the upper Mississippi River near La Crosse, Wisconsin (Navigational Pools 7 and 8) and Keokuk, Iowa (Navigational Pool 19). Body weights varied (P < 0.001) by age and sex without interaction. Weights varied by year (P < 0.001) on Pools 7 and 8. Mean weights increased (P < 0.01) within age and sex classes by date and averaged 3.6 and 2.7 g daily on Pools 7 and 8 and Pool 19, respectively. Percent fat was highly correlated (P < 0.001) with carcass weight for each age and sex. Live weight was a good predictor of total body fat. Mean estimated total body fat ranged from 200 to 300 g and comprised 15-20% of live weights among age and sex classes. Temporal weight patterns were less variable for adults than immatures, but generally increased during migration. Length of stopover varied inversely with fat reserves among color-marked adult males. Variation in fat condition of canvasbacks during fall may explain the mechanism regulating population ingress and egress on stopover sites. Fat reserves attained by canvasbacks during fall stopover may have adaptive significance in improving survival by conditioning for winter.

Journal of Wildlife Management↗