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T. W. Custer

Publications and source records attributed to T. W. Custer.

88 records · Page 5Linked to original sources
USGS1985

Effects of wildlife of ethyl and methyl parathion applied to California USA rice fields

Selected rice fields on the Sacramento National Wildlife Refuge Complex were aerially sprayed one time during May or June 1982 with either ethyl (0.11 kg Al/ha) or methyl (0.84 kg AI/ha) parathion for control of tadpole shrimp, Triops longicaudatus. No sick or dead vertebrate wildlife were found or adjacent to the treated rice fields after spraying. Specimens of the following birds and mammals were assayed for brain cholinesterase (ChE) activity to determine exposure to either form of parathion; house mouse, Mus musculus; black-tailed jackrabbit, Lepus californicus; mallard, Anas platyrhynchos; ring-necked pheasant, Phasianus colchicus; American coot, Fulica americana; and red-winged blackbird, Agelaius phoeniceus. Both mice and pheasants from methyl parathion-treated fields had overall mean ChE activities that were significantly (P < 0.05) inhibited compared with controls, and 7, 40, 54 and 57% of individual blackbirds, pheasant, mice, and coots, respectively, had inhibited brain ChE activities (i.e., less than -2 SD of control mean). Although no overall species effect was detected for ethyl parathoid treatment, pheasants (43%), coots (33%), and mice (37%) had significantly inhibited brain ChE activities. Neither of the parathion treatment appeared acutely hazardous to wildlife in or adjacent to rice fields, but sufficient information on potential hazards was obtained to warrant caution in use of these chemicals, especially methyl parathion, in rice fields.

California Fish and Game↗
USGS1984

Occurrence and timing of second clutches in common terns

Eighteen pairs of Common Terns (Sterna hirundo) at three different colonies laid second clutches while still feeding young from their first broods. Seven clutches were laid before the chicks from the first brood fledged, and 11 were laid after the chicks from the first brood fledged. In each case, parents alternately fed chicks from the first brood and incubated the second clutch. Sixteen of the 18 clutches disappeared, were addled, or were deserted. Young hatched from the two other second clutches, but all chicks died or disappeared 2-4 days after hatching. We suggest that a second clutch, laid before chicks from the first brood fledged, probably results from a physiological miscue associated with chick loss from the first brood and stimulated by an unusual surplus of food. Conversely, when laid after chicks from the first brood fledge, a second clutch might function as insurance, permitting a pair to raise young late in the season if chicks from the first brood are lost. In either case, parents must partition care between eggs and chicks from the second clutch and fledged chicks from the first brood. Accordingly, the successful fledging of chicks from two broods in a single season is unlikely unless exceptionally favorable conditions occur.

The Auk↗
USGS1984

Tissue lead distribution and hematologic effects in American kestrels (Falco sparverius) fed biologically incorporated lead

American kestrels were fed a diet containing 0.5, 120, 212, and 448 ppm (dry wt) biologically incorporated lead (Pb) for 60 days. The diet consisted of homogenized 4-wk-old cockerels raised on feed mixed with and without lead. No kestrels died and weights did not differ among treatment groups. The control group (0.5 ppm Pb) had the lowest mean concentration of lead and the high dietary group had the highest for the following tissues: Kidney, liver, femur, brain, and blood. Concentrations of lead were significantly correlated among tissues. There were no differences among treatment groups for packed cell volume, hemoglobin concentration, or erythrocyte count.

Journal of Wildlife Diseases↗
USGS1983

Heavy metal residues in prefledgling black-crowned night-herons from three Atlantic coast colonies

Aquatic birds may serve as indicators of regional metal contamination. Because the food of prefledgling herons (Nycticorax nycticorax ) comes only from areas near the colony, their tissues should reflect local metal contamination. The authors' hypothesis was that prefledgling herons from the Rhode Island colony should have higher concentrations of metals than do those from either the North Carolina or Massachusetts colonies.

Bulletin of Environmental Contamination and Toxico↗
USGS1983

Organochlorine residues in Atlantic coast black-crowned night-heron eggs, 1979

Eggs of Black-crowned Night-Herons (Nycticorax nycticorax) were collected in 1979 from two colonies in North Carolina, two colonies in Rhode Island, and one colony in Massachusetts. Mean concentrations of DDE and PCBs were higher in the New England samples than in those from North Carolina, Mean concentrations of organochlorine contaminants in addled eggs collccted at two New England colonies were not significantly different from those in randomly selected eggs. In comparison with the results of a similar study conducted in 1973 at two of the New England colonies, concentrations of DDE in night-heron eggs were lower in 1979, DDD was less frequently detected, DDT and dieldrin were less frequently detected in eggs from one of the two colonies, and eggshell thickness was greater in 1979 for one of the colonies. PCB concentrations in eggs from one colony were lower in 1979 than 1973.

Colonial Waterbirds↗
USGS1983

Organochlorine residues in common tern eggs from nine Atlantic coast colonies, 1980

In 1980, 178 Common Tern (Sterna hirundo) eggs were collected in nine colonies from Rhode Island to North Carolina and were analyzed for organochlorines. DDE and PCBs were detected in most of the eggs. Mean concentrations of DDE and PCBs differed among colonies and seemed related to local contamination. Concentrations of DDE and PCBs in Common Tern eggs were well below those reported to have adverse effects in this species. In one colony, eggs of known laying sequence were collected. First, second, and third eggs in the clutch did not differ significantly from one another in shell weight, shell thickness, and concentration of DDE or PCBs.

Colonial Waterbirds↗
USGS1983

Organochlorine residues and shell characteristics of roseate tern eggs, 1981

Roseate Terns ( Sterna dougallii ) breed in two areas in the Western Hemisphere: in northeastern North America between Long Island, New York, and Nova Scotia, and around the Caribbean Sea from the Florida Keys and the Bahamas to the Netherlands Lesser Antilles (Bent 1921, Bond 1956, Nisbet 1980). Both populations are small, and concern recently has been expressed about their status (Nisbet 1980, Buckley and Buckley 1981). The northeastern population has decreased from a peak of about 8500 pairs in the 1940s to between 2500 and 3000 pairs in 1978-1982, and has become largely concentrated into 4 colonies (Nisbet 1980). The Caribbean population has been affected by egg collecting and other forms of human disturbance in its main stronghold in the U.S. Virgin Islands (U.S. Virgin Islands Bureau of Fish and Wildlife 1976-1979, Norton 1980, 1981). One factor which may have affected the northeastern population is chemical pollution. Hays and Risebrough (1972) reported high levels of polychlorinated biphenyls (PCBs) and l,l-dichloro-2,2-bis(p-chloro phenyl) ethylene (DDE) in 3 Roseate Tern chicks found with congenital abnormalities at Great Gull Island, New York, in 1970. High levels of PCBs were also found in chicks found dead at Bird Island, Massachusetts, in 1970 (Nisbet 1981). A close relative, the Common Tern ( S. hirundo ), is relatively sensitive to the effects of DDE; elevated residues of DDE in eggs are associated with eggshell-thinning (Switzer et al. 1973), reduction in the porosity of eggshells, and embryonic mortality (Fox 1976). The present paper reports the results of a survey of organochlorine residues in Roseate Terns in 1981. The main objectives of the survey were to determine the levels of organochlorine contamination in eggs of the Roseate Tern in its major colonies and to investigate whether changes in eggshell characteristics similar to those reported by Fox (1976) may have occurred in this species. A secondary objective was to determine geographic patterns of organochlorine contamination within the northeastern U.S. population of Roseate Terns and to compare them with patterns observed in Common Terns

Connecticut, Massachusetts, New York↗
USGS1982

Estimating reproductive success in colonial waterbirds: An evaluation

To estimate reproductive success in a population one ideally would like to determine the number of young fledged per nesting female. However, this is difficult because often (1) the adults are not individually marked, (2) the colony is not visited daily, and (3) the investigator is unable to monitor all young until they fledge. If adults are unmarked and successful renesting occurs, reproductive success will be underestimated. If a colony is not visited daily and nests are initiated and lost between visits, reproductive success will be overestimated. The Mayfield method is one approach to overcoming this latter problem. Finally, nestling colonial birds are often able to move away from the nest site well before fledging and thus avoid being detected. To overcome this problem capture-recapture methods and enclosures have been used. In this paper we discuss these limitations and evaluate methods of dealing with them.

Colonial Waterbirds↗
USGS1981

Common tern colonies along the mid-Atlantic coast. I. Nestling chronology

1. Sixteen Common Tern colonies in Rhode Island, New Jersey, Virginia, and North Carolina were studied from May through July 1980 by four investigators. Nests were marked during egg laying and were monitored every 5-7 days until fledging of young. 2. Results from 1980 indicate that ambient temperature differences in the four study areas account for differences in the onset of egg laying with North Carolina and Virginia colonies beginning 12-16 days before New Jersey and Rhode Island birds. Temperature alone, however, does not seem to have a significant effect on either median egg-laying dates or total duration of the season. 3. The low frequency of late-season nesting was not correlated with colony size or success of peak nests in 1980, but renesting (or late nesting) in all study areas was rare because of the benign weather conditions during the spring. Similarly, no significant correlation was found between success of nests and colony size.

Colonial Waterbirds↗
USGS1980

Reproductive success and nest attentiveness of mallard ducks fed Aroclor 1254

A dietary dosage of 25 ppm Aroclor 1254 fed to nine-month-old mallards Anas platyrhynchos for at least a month before egg-laying had no detrimental effect on reproductive success or nest attentiveness when hens were allowed to incubate their own eggs. The treatment caused no effect on number of hens laying, date of first egg laid or clutch size. Fertility of eggs was greater among Aroclor-treated birds (87·7%) than among controls (73·2%). Aroclor may have stimulated males to come into reproductive condition sooner than controls. Hatching of fertile eggs and survival of ducklings to 3 weeks of age were similar in treated and control groups. The number of times off the nest per day and total time off the nest per day were the same for control and Aroclor-treated hens in days 14–17 of incubation.

Environmental Pollution (Series A)↗
USGS1978

Seasonal trends in summer diet of the lapland longspur near Barrow Alaska USA

Contents of lapland longspur [Calcarius lapponicus] stomachs and esophagi were sampled near Barrow, Alaska [USA], from May-Aug. in 1969, 1971, 1972 and 1973. Data from stomach contents were corrected for differential digestion of prey items. Longspurs shifted seasonally from larval to adult arthropods and back to larvae, responding to changes in the abundance of these prey items. Seeds were a vital supplementary food in late May and Aug., when arthropods were scarce or inaccessible. One species of crane fly was the major dietary component for longspurs during June and July. Its high abundance and substantial dry weight per individual may contribute to the success of longspurs at Barrow. The diets of longspurs and 4 common shorebirds (Calidris spp.) at Barrow were similar in the range of prey items taken except for seeds and tenthredinid larvae. Their diets overlapped closely when feeding sites were restricted because of snow and surface water (chiefly at the beginning of the season) and when prey was abundant in early to mid-July. Competition is possible early in the season but unlikely in July when surface insects are very abundant. Habitat separation and the advantages of fringillid form apparently contribute to the success of longspors in a tundra community of insectivores dominated by shorebirds.

The Condor↗
USGS1973

Snowy owl predation on lapland longspur nestlings recorded on film

During the summer of 1971 I investigated the breeding biology of the Lapland Longspur, Calcarius lapponicus , near Barrow, Alaska. To obtain data on incubation and feeding patterns of nesting longspurs, time-lapse cameras (Minolta Autopak-8 D6 super-8 movie cameras equipped with an Intervalometer-P time-lapse device) were positioned at several nests throughout the nesting season with an exposure interval of either 8 or 30 seconds. At 07:00 on 14 July a Snowy Owl, Nyctea scandiaca , took the three largest of four young at a nest being monitored at 30-second intervals (Figure 1). The nestlings were 4, 6, 7, and 8 days posthatching and weighed approximately 12, 15, 20, and 20 g respectively on 13 July.

The Auk↗