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Research about Patuxent Wildlife Research Center

Source-linked reports with geographic coverage including Patuxent Wildlife Research Center.

At least 19 recordsLinked to original sources
USGS2022

Density estimation in terrestrial chelonian populations using spatial capture–recapture and search–encounter surveys

Having an accurate estimate of population size and density is imperative to the conservation of chelonian species and a central objective of many monitoring programs. Capture–recapture and related methods are widely used to obtain information about population size of chelonians. However, classical capture–recapture methods have strict spatial sampling requirements and do not account for lack of geographic closure caused by movement of individuals in and out of the surveyed landscape. Newly developed spatial capture–recapture (SCR) models address these limitations by specification of explicit models for spatial sampling as well as the spatial distribution of individuals in the population. Spatial capture–recapture models have not yet been applied to the study of chelonian populations. Here we demonstrate their application to a population of box turtles in Maryland that has been studied for 75 yr. Results support dramatic declines in population size of box turtles since the 1940s.

Maryland↗
USGS2008

Atlantic Flyway review: Region IV Piedmont-Coastal Plain, Fall 2007: Patuxent powerline right-of-way (390-0764)

This station operates at the Patuxent Research Refuge in a powerline right-of-way that bisects an upland deciduous forest. This area has been used for this purpose since 1980, except in the years 2004-2006. Twenty-six nets are arrayed along approximately one-half mile that runs generally on an east-west orientation. The habitat is marked by dense 4-6 foot high shrub foliage with very few trees of any height. Trees are purposely kept to a minimum within the right-of-way to avoid arcing with the powerlines. We operated seven days in August and November and 14 days in September and October for a total of 42 days, generally on a M/W I F schedule. Nets were opened · by 25-30 minutes before sunrise, and closed about 3.5 hours later. Weather did not have a significant impact on our operations. We did have a few mornings in late October when some nets were frozen, delaying their opening. Only once (13 Nov) did rain necessitate closing nets early.

Maryland↗
USGS2004

Atlantic Flyway review: Region IV - Fall 2003: Patuxent powerline right-of-way (390-0764)

The station was operated on fewer days than usual in 2003, opening a bit later, closing a week early, and missing several good days in September through mid-October, when the manager/lead bander was conducting research on migrating birds in Lower Delmarva. As a result, capture totals for many species are not comparable to other years, and totals for several species, including House Wren, Northern Parula, Nashville Warbler, Blackthroated Green Warbler, Bay-breasted Warbler, American Redstart, Connecticut Warbler, and Common Yellowthroat, set record lows. Fifty-three birds banded in previous years were captured, all of species that either nest or. winter here. Included were a record high 16 Gray Catbirds, nine of which were hatching-year (HY) birds when banded. Six return Red-eyed Vireos were captured, again far fewer than during the station's first 20 years of operation; the oldest, an adult when banded in Aug 1998, was last captured in Aug 2000. Other highlights were captures of a Cerulean Warbler (HY male), a Marsh Wren, an American Tree Sparrow, and a Northern Saw-whet Owl with a meadow jumping mouse ( Zapus hudsonius ) in its talons. Special thanks to Danny Bystrak, who operated the station on many mornings during my absence. Thanks also to Marty Barron, Murray Efford, Cecilia Leumas, Woody Martin, Diann Prosser, Mike Quinlan, Gemma Radko, Jack Saba, and John Sauer, who provided regular or occasional assistance. Sara Campbell, assistant of Dr. Peter Marra at the Smithsonian Environmental Research Center, collected blood samples from over 500 birds to test for exposure to West Nile Virus. Results are not yet available.

Maryland↗
USGS2003

Population dynamics of Microtus pennsylvanicus in corridor-linked patches

Corridors have become a key issue in the discussion of conservation planning: however, few empirical data exist on the use of corridors and their effects on population dynamics. The objective of this replicated, population level, capture-re-capture experiment on meadow voles was to estimate and compare population characteristics of voles between (1) corridor-linked fragments, (2) isolated or non-linked fragments, and (3) unfragmented areas. We conducted two field experiments involving 22600 captures of 5700 individuals. In the first, the maintained corridor study, corridors were maintained at the time of fragmentation, and in the second, the constructed corridor study, we constructed corridors between patches that had been fragmented for some period of time. We applied multistate capture-recapture models with the robust design to estimate adult movement and survival rates, population size, temporal variation in population size, recruitment, and juvenile survival rates. Movement rates increased to a greater extent on constructed corridor-linked grids than on the unfragmented or non-linked fragmented grids between the pre- and post-treatment periods. We found significant differences in local survival on the treated (corridor-linked) grids compared to survival on the fragmented and unfragmented grids between the pre- and post-treatment periods. We found no clear pattern of treatment effects on population size or recruitment in either study. However, in both studies, we found that unfragmented grids were more stable than the fragmented grids based on lower temporal variability in population size. To our knowledge, this is the first experimental study demonstrating that corridors constructed between existing fragmented populations can indeed cause increases in movement and associated changes in demography, supporting the use of constructed corridors for this purpose in conservation biology.

Maryland↗
USGS2000

Effects of the mosquito larvicides temephos and methoprene on insect populations in experimental ponds

The nontarget effects of Abate® 4E (44.6% temephos) at 0.054 kg of active ingredient (a.i.) per 1 ha and of Altosid® Liquid Larvicide (5% methoprene) at 0.011 kg a.i./ha were investigated in 18 experimental ponds (average area, 202 m 2 ; maximum depth, 0.7 m) at Patuxent Wildlife Research Center, Laurel, Maryland, USA. Ponds were sprayed three times at 3-week intervals. Six ponds were sprayed with Abate, six with Altosid, and six with distilled water. Two insect-emergence traps per pond collected for 7 d and were then harvested 1 d before each spray and 13 to 14 days afterward. A repeated measures analysis of variance (ANOVA) revealed significant reductions in Shannon diversity, equitability, and numbers of individuals, species, and families in the Abate ponds relative to controls. Significant reductions also occurred in Ephemeroptera, Odonata, Diptera, Chironomidae, and Chaoborus sp. Hester-Dendy samplers were installed before spray one and harvested 16 d after spray three. Based on one-way ANOVA, Shannon diversity, equitability, and number of Ephemeroptera and Chironomidae were significantly reduced in the Abate ponds. Emergence data indicate only isolated cases with significant reductions in the Altosid ponds relative to controls, and the Hester-Dendy data indicate no significant differences between the Altosid and control ponds.

Maryland↗
USGS2000

Atlantic Flyway review: Piedmont-Coastal Plain, Region IV, Fall 1999: Patuxent powerline right-of-way (390-0764)

Fall 1999 was among the poorest seasons in this banding station's 20 years of operation. Record high capture totals were set for only two species: Ruby-throated Hummingbird (41 individuals captured, none banded; previous high 21) and White-breasted Nuthatch (two individuals banded; previous high, one). The only other species that stood out as being unusually numerous was Blackpoll Warbler, for which the banding total (33 birds) was the highest since 1988. Bandings of several species (Red-eyed Vireo, Tennessee Warbler, Nashville Warbler, Ovenbird, Hooded Warbler, Canada Warbler, Eastern Towhee, and Field Sparrow) were at record lows, and bandings of many other species were below the long-term (1980-1998) mean. The number of species banded was also below the long-term mean of 86 species, and tied the previous low. Possible contributing factors included drought conditions in Maryland and elsewhere in the East, which may have influenced nesting productivity and migration dates for some species; Hurricanes Dennis and Floyd, which influenced East Coast weather through much of September; the unprecedented scarcity of Hercules' Club ( Aralia spinosa ) fruits at the banding station; and occasional visits by a gray fox, which reduced operation of some nets in October and November. A season highlight was the August capture of 37 Red-eyed Vireos banded at this station in previous years, including a bird banded in August 1989. These are almost certainly locally nesting birds that feed on the abundant fruits of Viburnum dentatum in the powerline right-of-way in late summer. Regular assistants at the banding station included Woody Martin, Susie Michaelson, Jane Nicolich, Gemma Radko, Jack Saba, Julie Tomita, and Laurie Walter. Danny Bystrak and Mary Gustafson each served as bander-in-charge on several mornings.

Maryland↗
USGS1988

Postfledging survival of European starlings exposed as nestlings to an organophosphorus insecticide

To test the hypothesis that exposure to organophosphorus (OP) insecticides reduces postfledging survival of altricial birds, 16—d—old European Starlings ( Sturnus vulgaris ) were weighed and orally dosed with corn oil containing 6.0 mg of dicrotophos per kilogram of body mass or an equivalent exposure of pure corn oil (controls). Two days later, each survivor was weighed again and patagially tagged for identification after fledging. Resightings of marked fledglings were made during weekly 2—d intensive observations yielding four estimates of postfledging survival. Before fledging, only OP—dosed birds died (18.5%), and OP—dosed survivors lost more mass (5.2%, P = .001) than controls (1.4%) but their masses on day 18 were only slightly lower (2% of control mean, P = .10). Brain cholinesterase activity, a sensitive indicator of OP exposure in birds, was depressed and average of 93% in OP—dosed nestlings that died compared to controls, and an average of 46% in OP—dosed nestlings alive on day 18. Age at fledging, postfledging survival, flocking behavior, and habitat use, however, did not differ between OP—dosed and control birds. The effects of the OP on the nestlings appeared to be rapid, to be reversible in survivors, and did not extend into the postfledging period. In addition, we found no relationship between body mass at fledging and postfledging survival.

Maryland↗
USGS1987

Toxicity of paraquat in nestling birds: effects on plasma and tissue biochemistry in American kestrels

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 days. Plasma LDH activity and total protein concentration were elevated, and plasma alkaline phosphatase activity was lower in survivors of the 60 mg/kg group at 10 days. Lung total sulfhydryl (TSH) and protein-bound sulfhydryl (PBSH) concentrations were significantly higher in the 10 mg/kg, 25 mg/kg, or 60 mg/kg groups. Lung DNA, RNA, protein, and hydroxyproline (collagen) concentrations were not significantly affected by treatment. Liver NPSH was lower in the 60 mg/kg group while liver glycogen concentration was not affected by treatment. Kidney DNA, RNA, and RNA to protein concentration ratio were higher in the 25 mg/kg or 60 mg/kg groups. These findings in combination with recently reported effects on growth and histopathology suggest that altricial nestling kestrels are more sensitive to paraquat exposure than young or adult birds of precocial species. From a comparative viewpoint, lungs of nestling kestrels are less sensitive to paraquat than mammalian lungs.

Maryland↗
USGS1986

Mortality of captive whooping cranes caused by eastern equine encephalitis virus

Of 39 captive whooping cranes (Grus americana), 7 died during a 7-week period (Sept 17 through Nov 4, 1984) at the Patuxent Wildlife Research Center, Laurel, Md. Before their deaths, 4 cranes did not develop clinical signs, whereas the other 3 cranes were lethargic and ataxic, with high aspartate transaminase, gamma-glutamyl transferase, and lactic acid dehydrogenase activities, and high uric acid concentrations. Necropsies indicated that the birds had ascites, intestinal mucosal discoloration, fat depletion, hepatomegaly, splenomegaly, and visceral gout. Microscopically, extensive necrosis and inflammation were seen in many visceral organs; the CNS was not affected. Eastern equine encephalitis (EEE) virus was isolated from specimens of the livers, kidneys, lungs, brains, and intestines of 4 of the 7 birds that died, and EEE virus-neutralizing antibody was detected in 14 (44%) of the 32 surviving birds. Other infectious or toxic agents were not found. Morbidity or mortality was not detected in 240 sandhill cranes (Grus canadensis) interspersed among the whooping cranes; however, 13 of the 32 sandhill cranes evaluated had EEE virus-neutralizing antibody. Of the 41 wild birds evaluated in the area, 3 (4%) had EEE virus-neutralizing antibody. Immature Culiseta melanura (the most probable mosquito vector) were found in scattered foci 5 km from the research center.

Maryland↗
USGS1985

Atlantic Flyway review: Region V: Patuxent Wildlife Research Center, Laurel, Prince Georges County, MD (390-0764)

This was my 4th year of banding in a powerline right-of-way that is specially managed to encourage growth of dense scrub. Nets were run for 2 to 3 hours each morning, because activity dropped off rapidly after the sun hit the nets. I banded on 79 days, from 1 August to 22 November. Frost continues to be a problem late in the season; the frostpocket effect of the stream valley and the lack of vegetative cover over the nets result in frozen nets on more mornings than would be expected. Warblers continued to dominate, with as many as 16 species in one day and a season total of 33 plus a Brewster's hybrid. Net-hours declined from 8506 to 7672 because I discontinued six of my least productive nets; this change accounted for much of the increase in birds per 100 net-hours (Table 1). Overall effort was comparable to that of 1982.

Maryland↗
USGS1980

Toxic effects of endrin and toxaphene on the southern leopard frog Rana sphenocephala

Eggs, larvae and sub-adults of the southern leopard frog Rana sphenocephala were exposed to endrin and toxaphene. Exposure was in water by a continuous-flow technique, following standards that have been used successfully in the study of fish and invertebrates. R. sphenocephala is more sensitive to both pesticides than are higher vertebrates but is slightly less sensitive than fish. Eggs seem to be resistant to the effects of both pesticides and are probably poor indicators of environmental hazard. The toxic level of endrin is about equal in larvae and transformed frogs (LC 50 , 0·005-0·015 ppm). Toxaphene is less toxic to sub-adults (LC 50 , 0·37-0·790 ppm) than to larvae (LC 50 , 0·032-0·054 ppm). Delayed mortality, behavioural aberrations and effects on growth have been seen in toxaphene-dosed larvae observed over 30-day periods. Behavioural effects are more severe than those reported in other groups of animals. Effects on growth resulting from a 96-h exposure begin in the 0·013-0·018 ppm range. The maximum accumulation of residues observed for each chemical represented bioconcentration factors of about 100. Endrin residues are apparently lost more readily than toxaphene residues; relative depuration rates correlate well with the time course of toxic action in each chemical. Although less sensitive to these pesticides than fish, amphibians may not be protected in their natural habitats. Future studies of the effects of toxicants on amphibians should employ larvae if only one stage can be tested, should expose subjects for at least 96 h and should continue observations for a total of at least 30 days.

Maryland↗
USGS1979

Environmental contaminant studies by the Patuxent Wildlife Research Center

Evaluation of the effects of environmental contaminants on wildlife is geared to interpreting events in the field, especially population effects, and both field and laboratory studies are planned for this purpose; procedures are adapted to specific problems and therefore do not include strict protocols or routine testing. Field evaluations include measurements of cholinesterase inhibition in brain or blood, search for dead or disabled animals, study of nesting success of birds, and general ecological observations. Residue analyses are used in evaluating organochlorine chemicals; samples may include whole bodies for determining level of exposure, brains for mortality diagnosis, whole blood for certain special studies, and eggs to help in evaluation of possible reproductive effects. Bird counts, singing-male census counts, small mammal trapping, and cage-in-field tests have proven to be ineffective or misleading and are not considered suitable for field evaluations under most circumstances. Usefulness of simulated field trials is limited to very special situations. Experimental studies that help predict and interpret field effects include determinations of lethal diagnostic levels, comparative lethal dietary toxicity tests, tests of secondary poisoning, measurement of residue loss rates, measurement of blood enzymes, tests of behavioral effects, and studies of reproductive effects.

Maryland↗
USGS1974

Salmonellosis in a captive heron colony

Salmonellosis caused by Salmonella typhimurium was one of several factors responsible for losses among young herons being held at the Patuxent Wildlife Research Center. The infection was demonstrated in five black-crowned night herons ( Nycticorax nycticorax ), three common egrets ( Casmerodius albus ), two little blue herons ( Florida caerulea ), one cattle egret ( Bubulcus ibis ), one snowy egret ( Leucophoyx thula ) and one Louisiana heron ( Hydranassa tricolor ). The disease was characterized by emaciation, focal liver necrosis, and frequently by a caseo-necrotic enteritis.

Maryland↗
USGS1971

A starling-deterrent wood duck nest box

In many parts of the United States, the starling ( Sturnus vulgaris ) has I become a serious competitor for nest boxes erected for wood ducks ( Aix sponsa ). Research at the Patuxent Wildlife Research Center and at Eastern Neck National Wildlife Refuge near Rock Hall, Maryland, demonstrated that horizontal nest structures with semicircular entrance holes 11 inches in diameter were acceptable to nesting wood ducks but discouraged nesting by starlings. Starlings seemed to prefer boxes in open impoundments to those in wooded impoundments, whereas wood ducks seemed to show no preference.

Maryland↗