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Research about Laurel, Maryland

Source-linked reports with geographic coverage including Laurel, Maryland.

At least 19 recordsLinked to original sources
USGS2008

Atlantic Flyway review: Region IV Piedmont-Coastal Plain, Fall 2007: Robbins Nest, Laurel, MD (390-0765)

After a gap of two years I resumed banding at this suburban fall-line station on the Patuxent River, my 33rd fall banding season on our two-acre wooded lot. I banded three mornings per week, trying to keep the same schedule as the Patuxent powerline station five miles downstream. I used half as many nets as they did and captured only 15% as many birds. Their location in a large undeveloped area combined with their managed shrub habitat probably accounted for most of the difference. The powerline station favored warblers and kinglets; I did better on cardinals and thrushes. I have witnessed a continuing decline in warblers. In 1997 and 1998 I was still getting four species of warblers among my top ten, and then two or three warbler species through 2004; 2007 was my first year with no warblers among my top ten species. My oldest recapture was a 1 0-year-old Gray Catbird (8051-36905) banded as an AHY on 18 Aug 1998.

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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.

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USGS2005

Atlantic Flyway review: Region IV, Piedmont-Coastal Plain, Fall 2004: Robbins Nest, Laurel, MD (390-0765)

The continuing decline in migratory species is depressing. For a 'migration station' to report Northern Cardinal as the species most commonly banded during the autumn months came as a real shock, especially when the cardinal was so far ahead of second-place catbird. I caught twice as many cardinals as all sparrows combined (including juncos), and the total for cardinals came within ten birds of the total for all warblers combined. Warblers comprised only 16.8% of this fall's catch, compared with an average of 21.7% for the previous five years. Hurricanes Bonnie and Frances passed to the east of us and Charles and Ivan to the west, but none was followed by a landfall of migrants. Last year I reported the sharp drop in Tufted Titmice and Carolina Chickadees locally and the small number of returns from prior years. This year, after no overwintering titmice, numbers have returned to nearly normal, but chickadee numbers are still only half normal. I recaptured cardinals from each year back to 1999, but the only other birds more than two years old were a Carolina Wren and two titmice banded in the autumn of 2000.

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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.

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USGS2004

Atlantic Flyway review: Region IV - Fall 2003: Robbins Nest, Laurel, MD (390-0765)

The most notable finding at this station in 2003 was the sharp decline in recaptures of previously banded birds and most especially a Crash in the chickadee and titmouse populations. In the autumn of 2001, I recaptured 36 birds banded in previous autumns, but I caught only 24 returns in 2002 and 17 in 2003, a 33% drop each year. In 2002, Tufted Titmouse was my fourth most common species (19 caught) and Carolina Chickadee (15)was in seventh place. This year, I had only four titmice and six chickadees, declines of 79% and 60%. Until now, only the migratory species have been of concern. We suspect West Nile virus is responsible. However, the oldest bird we recaptured this year was Blue Jay 723-42798, banded as HY in 1993, a species known to be especially vulnerable to West Nile. Half of this year's returns were cardinals, the oldest of which was only four years of age. My birds/100nh continues to drop each year without any noticeable change in surrounding habitat. The only banded migrant known to have remained here for more than a week was a Swainson's Thrush that weighed 31.9 g on 4 Oct and 41.6 g nine days later, an increase of 30%.

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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.

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USGS2002

The effects of polychlorinated biphenyls (Aroclor 1242) on thyroxine, estradiol, molt, and plumage characteristics in the American kestrel (Falco sparverius)

The purpose of this experiment was to determine the effects of Aroclor 1242, a mixture of polychlorinated biphenyls (PCBs), on plumage characteristics and molt in the American kestrel, Falco sparverills . Several characteristics of plumage. including color and molt schedule, are modulated by hormonal signals and hence may be modified by endocrine-active contaminants. If so, the functions of plumage (e.g. communication for mating or territorial defense) may be compromised by exposure to such compounds. Captive American kestrels were fed Aroclor 1242 at 0. 6.0. and 60.0 ppm (n = 6 males and 6 females per treatment) mixed in their normal diet. Concentrations of plasma estradiol and thyroxine were measured weekly from the beginning of treatment. Measured plumage characteristics included width of the black subterminal band on the tail, color (a composite index of hue and saturation), reflectance from 230 to 800 min. pattern of feather loss and regrowth on the tail and wing. and timing of onset and duration of molt. Aroclor 1242 depressed plasma thyroxine. Plasma estradiol levels remained low due to the phase of the breeding cycle. Treatments did not disrupt the measured plumage characteristics. This may be due to timing or dose of exposure or to genetic factors.

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USGS2002

Atlantic Flyway review: Piedmont-Coastal Plain, Region IV, Fall 2001: Robbins Nest, Laurel, MD (390-0765)

I continue to band before and after work and all day on weekends on my two and a half acres along the Patuxent River gorge between highway 1-95 and the Laurel city limits. Our kids have long since flown the coop, so I have no one to run the station when I am out of town; thus, I miss some of the best flight days. The chief changes in habitat over the years have been replacement of pines by young deciduous growth, loss of dogwoods in the mature deciduous forest, and gradual replacement of lawn by shrubbery. To explore changes in fall migration patterns, I compared my banding totals for the first five years of systematic fall banding with those of the most recent five years. By coincidence the totals were nearly identical: 2175 birds in 1973-1977 and 2169 in 1997-2001. However, my net hour totals were vastly different: 9124 in the first five years compared with 26,284 for the current period. It took nearly 2.9 times the effort to catch the same number of birds I used to band. Next year, my 30 th , I'll be checking to see which species I am losing and which are maintaining their numbers. I had 35 returns of a dozen species, but all were either summer, winter, or permanent residents. The oldest this time was only four years old, a Gray Catbird. Eleven transients repeated on a subsequent day. The one longest in residence was a Gray-cheeked Thrush that l captured 10 times in 17 days; it weighed 31.0 g when banded and reached a maximum of 51.7 g 13 days later.

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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.

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USGS2000

Atlantic Flyway review: Piedmont-Coastal Plain, Region IV, Fall 1999: Robbins Nest, Laurel, MD (390-0765)

This is the first of three stations along the Patuxent River. Elevation here at the edge of the Piedmont ranges from 265 ft at the house to 160 ft at the river. In spite of easterly winds and heavily overcast skies from Hurricanes Dennis, Floyd, and Irene, we suffered from drought all summer, not rain. We had only about two inches each in June and July, 4.55 in August, then a whopping 16.03 in September, and a normal 3.46 in October. This station operates all day on weekends, but only before and after work on other days. Net-hours were 5% above the 26-year mean of 3655, but way down from last year because other commitments kept me out of town on several weekends. I had only 14 days when I could net all day. Although the most birds were banded on opening day, the most per net-hour were on 19 and 15 October and 23 September. The nets caught 26 returns from prior years, the oldest being a seven-year-old Blue Jay and a seven-year-old cardinal. To illustrate how biased a sample one can obtain from netting, I captured only one junco in the nets, but caught 47 of them in baited traps on our deck. Other species taken only in the traps (and not included in the totals) were Mourning Dove, Chipping Sparrow, House Finch, Pine Siskin, and American Goldfinch.

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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.

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USGS1998

Atlantic Flyway review: Piedmont-Coastal Plain Region IV - Fall 1997: Robbins Nest, Laurel, MD (390-0765)

The 25th year of fall banding at this back yard station atop the Patuxent River gorge between Laurel and the 1-95 bridge netted more birds of summer and winter resident species than migrants. Myrtle Warbler was the only one of the six commonest species captured that is primarily a transient here. My 5214 net-hours, my fourth highest, were 48% above the 24-year mean of 3512, but the only species to exceed their previous high were Carolina Chickadee and Magnolia Warbler. Part of the reason for my low catch per 100 net-hours in recent years is the dieoff of dogwood from anthracnose and destruction of the shrub layer in my mature woods by an overpopulation of deer. For the first time, deer destroyed three of my nets. We also had the driest summer in decades, which killed some of the shallow-rooted vegetation this year. The greatest declines from last year were in catbird (51 to 32), Hermit Thrush ( 27 to 12 ), and Blackand-white Warbler (11 to 3), and the greatest increases were in Myrtle Warbler (2 to 34), Carolina Chickadee (6 to 36), and Tufted Titmouse (10 to 31). The biggest changes from the mean of the first five years (1973-77) to the most recent five years (1993-97), not corrected for the 147% increase in net-hours, are increases in Rubythroated Hummingbird (1.2 to 7.6 ), Black-throated Blue Warbler (1.8 to 11.6), Common Yellowthroat (5.0 to 17.6), and House Finch (0.2 to 6.0), and decreases in Swainson's Thrush (26.6 to 17.2), Gray-cheeked/Bicknell's Thrush (9.4 to 3.8), Scarlet Tanager (6.6 to 2.2), and American Goldfinch (3.0 to 0.4). The oldest of my 39 returns were a six-year-old Gray Catbird and a five-year-old Carolina Chickadee. Two birds banded here during the fall migration of 1995 were found to the northeast of here in the summer of 1997: a Ruby-throated Hummingbird (8000-85102) in Philadelphia, PA, and a Hermit Thrush (1521-58503) at Wentworth, NH. A Savannah Sparrow was the 121st species banded on our suburban wooded hectare.

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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.

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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.

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USGS1983

Atlantic Flyway review: Region V: Laurel, Prince Georges County, MD (390-0765)

Nets were operated at this suburban backyard station before and after work during the week, and all day on as many weekends as possible, from 23 August to 30 November. A trip to Spain interrupted banding in mid-September and accounted for the drop in both species and individuals banded. This also explains the 66% drop in Gray Catbirds, which was by far my most common species last year. As in past years, no netting was done within 15 m of the bird feeders, and no traps were baited until the nets were removed in December. White-throated Sparrows (9) and Carolina Chickadees (7) accounted for half of my returns. The oldest returns were a 6-year-old White-throated Sparrow and a 7-year-old Carolina Chickadee. The only species banded in unusually large numbers were American Robin and Black-throated Blue Warbler. A Red-shouldered Hawk and a Golden-winged Warbler raised the species total for this station to 112. Three birds remained here long enough to increase their weight by more than 30%: an HY female Black-and-white Warbler arrived on 29 August with a weight of 11.2 g and was last captured on 5 September with a weight of 17.1 g. It took an HY Ovenbird 24 days to increase from 20.8 g to the 28.2 g that it weighed when last caught on 13 October. A Swainson's Thrush, on the other hand, went from 36.5 g to 48.1 g between 10 and 14 October. Other heavy-weights were Hairy Woodpecker, 74.4 g; Blue Jay, 103.2 g; Gray Catbird, 46.4 g; Wood Thrush, 64.1 g; and White-eyed Vireo, 15.0 g.

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USGS1980

Atlantic Flyway review: Region V: Laurel, Prince Georges County, MD (390-0765)

Despite a 22% increase in net-hours, the number of new birds banded dropped 26% from 1977. The decrease was noted in each month and was spread among all of the commonest species, including summer residents, winter residents, permanent residents, and transients. The greatest declines were in Scarlet Tanager (84%), Blue Jay (78%), Red-eyed Vireo (67%), Gray Catbird (62%), Ruby-crowned Kinglet (60%}, Mrytle Warbler (56%), Gray-cheeked Thrush (55%), Wood Thrush (44%0, Cardinal (38%), and White-throated Sparrow (30%). Of these species, only the Scarlet Tanager and Myrtle Warbler had been banded in unusually large numbers in 1977. Partly offsetting the decreases were a few increases: Veery (from 4 to 22 birds), Black-and-white Warbler (3 to 12), and Ovenbird (15 to 34). The four species that had been singled out for mention last year as being victims of the severe winter weather in 1976-77 - the Winter and Carolina Wrens and the Golden- and Ruby-crowned Kinglets - fared no better in 1978. The first three were banded in almost identical nnmbers to 1977, and the Ruby-crown dropped again as indicated in the first paragraph.

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USGS1977

Atlantic Flyway review: Region V: Laurel, Prince Georges County, MD

Robbins Nest is located on the fall line one-half mile below Rocky Gorge Reservoir. During the fall migration, about 8 nets are run on the upper part of the 3 acres (edge of the lawn, the garden, under the Virginia Pines, and the upper edge of the mature oak woods that drop 80 feet to the Patuxent River). Foul weather on weekends, combined with commitments away from home, severely restricted this season's operation. August banding was limited to the weekend of the 23-24th. In September, all-day netting was conducted on the 6-7th and 20-21st, and this was supplemented with before- and after-work banding on 16 other days. October banding also was limited to 4 whole days and parts of 16 others.

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