USGS Science⌕ Search

SEARCH · USGS Science

Results for “American Birds”

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 793 records · Page 44Linked to original sources
USGS1990

Bioaccumulation of selenium in birds at Kesterson Reservoir, California

This study was conducted to determine selenium (Se) concentrations in tissues of birds collected during the 1983-1985 nesting seasons at Kesterson Reservoir (an area receiving high-Se irrigation drainage water), compare them with birds from reference sites within California's Central Valley, and relate them to food-chain Se concentrations at the study sites. Within years, Se in livers of adult birds collected early and late in the nesting season changed significantly at both Kesterson and the primary reference site (Volta Wildlife Area). These changes were related to the length of time birds had been present at the study sites and the associated accumulation (at Kesterson) or depuration (at Volta) of Se. All species showed significant location differences, which were greatest in species that occurred at Kesterson throughout the year or fed more consistently within the reservoir. There were few species differences in Se for birds at the reference sites (where food-chain Se levels were 'normal' [ < 2?g/g, dry wt]). At Kesterson (where bird foods generally contained >50 ?/g Se/g), species patterns varied by year, probably because of varying periods of residence and other factors. Se concentrations in kidneys and livers of American coots (Fulica americana) were significantly correlated (r = 0.9845); Se concentrations in breast muscles and livers of juvenile ducks (Anas spp.) also were correlated (r = 0.8280). Body weights of adult coots were negatively correlated with liver Se concentration. Late-season resident breeding birds or pre-fledging juvenile birds reared at a site usually provided the best indication of site-specific Se bioaccumulation.

California↗
USGS2016

A potential predator-prey interaction of an American badger and an Agassiz's desert tortoise with a review of badger predation on turtles

The federally threatened Agassiz’s desert tortoise ( Gopherus agassizii ) was listed under the U.S. Endangered Species Act in 1990, but thus far, recovery efforts have been unsuccessful (U.S. Fish and Wildlife Service [USFWS] 2015). Predation has been identified as a contributing factor to declining G. agassizii populations range-wide (e.g., Esque et al. 2010, Lovich et al. 2014). Understanding and managing for predator-prey dynamics is thus an important part of the recovery and conservation of this threatened species (USFWS 2011). Desert tortoises have a host of predators at all stages of their life cycle. Over 20 species of birds, mammals, and reptiles have been recorded as known or suspected predators (Woodbury and Hardy 1948, Luckenbach 1982, Ernst and Lovich 2009). American badgers ( Taxidea taxus , family: Mustelidae) are confirmed excavators of desert tortoise nests (Turner and Berry 1984). They are also suspected predators of adult desert tortoises, a possibility which has been presented in some studies but without empirical verification (Luckenbach 1982, Turner and Berry 1984). Active mostly at night, badgers are solitary, secretive predators (Lindzey 1978, 1982; Armitage 2004) that are extremely difficult to observe in predatory encounters. Recently, strong circumstantial evidence presented by Emblidge et al. (2015) suggests that badgers do prey on adult Agassiz’s desert tortoises based on observations of more than two dozen dead tortoises in the Western Mojave Desert of California. In this note, we present another case of potential badger predation on a large adult desert tortoise in the Sonoran Desert of California. Collectively, these recent two cases potentially indicate that badger predation may be more common and widespread than previously thought. In addition, we review the worldwide literature of badger predation on turtles in general and summarize reported badger observations in Joshua Tree National Park, where our observation occurred, over a period of 55 years.

California↗
USGS2010

Circumpolar variation in morphological characteristics of Greater White-fronted Geese Anser albifrons

Capsule: Greater White-fronted Geese show significant variation in body size from sampling locations throughout their circumpolar breeding range. Aims: To determine the degree of geographical variation in body size of Greater White-fronted Geese and identify factors contributing to any apparent patterns in variation. Methods: Structural measures of >3000 geese from 16 breeding areas throughout the Holarctic breeding range of the species were compared statistically. Results: Palearctic forms varied clinally, and increased in size from the smallest forms on the Kanin and Taimyr peninsulas in western Eurasia to the largest forms breeding in the Anadyr Lowlands of eastern Chukotka. Clinal variation was less apparent in the Nearctic, as both the smallest form in the Nearctic and the largest form overall (the Tule Goose) were from different breeding areas in Alaska. The Tule Goose was 25% larger than the smallest form. Birds from Greenland (A. a. flavirostris) were the second largest, although only slightly larger than geese from several North American populations. Body size was not correlated with breeding latitude but was positively correlated with temperature on the breeding grounds, breeding habitat, and migration distance. Body mass of Greater White-fronted Geese from all populations remained relatively constant during the period of wing moult. Morphological distinctness of eastern and western Palearctic forms concurs with earlier findings of complete range disjunction. Conclusions: Patterns of morphological variation in Greater White-fronted Geese across the Holarctic can be generally attributed to adaptation to variable breeding environments, migration requirements, and phylo-geographical histories.

Bird Study↗
USGS1985

Determining age and sex of American coots

Reliable techniques for age and sex determination of migrating and wintering American Coots ( Fulica americana ) have not been available. Breeding coots can be ages through age 3 by tarsal color (birds 4 years and older were placed in a 4+ age class) (Crawford 1978), and males and females have sex-specific behaviors and calls while on breeding territories (Gullion 1950, 1952). Externally, juvenile coots differ from adults in having gray (as opposed to white) bills and brown (as opposed to red) eyes to an age of 75 days (Gullion 1954-394). Bill color changes to white by about 120 days. No quantitative data have been available, however, on the proportion of juveniles retaining these traits throughout fall and early winter. Nonbreeding coots can be ages as juvenile or adult by internal examination of the thickness of the wall of the bursa of Fabricius, although bursal depth does not predictably decline with age (Fredrickson 1968). Attempts to sex coots by single external measurements of combinations of measurements have met with mixed success. Eight-five percent of 101 fall migrants in Wisconsin could be sexed by the length of the metatarsus-midtoe including claw by using 139.5 mm as a cutoff point (Burton 1959), whereas 88% of 67 coots in California were correctly sexed by the length of the metatarsus-midtoe without claw using 127.5 mm as the cutoff point (Gullion 1952). Two-hundred-thirty-two of 291 coots collected in Iowa, however, were in the zone of overlap between the sexes for this measurement (Fredrickson 1968). Previous studies attempting to develop aging and sexing techniques for American Coots have been limited to a few study sites or to 1 season or year, often failing to take geographical, annual, and seasonal morphological variation into account (e.g., Visser 1976, Fjeldsa 1977). We designed the present study to refine and quantify external and internal age and sex criteria for postbreeding coots, with the objective of defining techniques applicable for all seasons over a wide geographical area.

Journal of Field Ornithology↗
USGS1975

Leech (Hirudinea) infestations among waterfowl near Yellowknife, Northwest Territories

Fourteen species of aquatic birds, including 11 species of ducks, were infested with leeches Theromyzon rude and Placobdella ornata near Yellowknife, Northwest Territories. Leeches infested 88% of 41 American Wigeon (Anas americana) and 31% of 86 Lesser Scaup (Aythya affinis) examined after death. Lesser Scaup captured by drive-trapping contained significantly more leeches than undisturbed ducks. Leeches were attached to the host within the mucosa of the nasal chamber, to the conjunctiva of the eye and on the skin of the body. Although only two deaths of ducklings were directly attributed to leech infestations, other birds probably died as a result of parasitism by leeches.

Northwest Territories↗
USGS2025

Sapsucker wells as a keystone nutritional resource: Evaluating methods for detection of secondary sap consumers

North American sapsuckers are considered double keystone species because they (1) excavate nest cavities that are used by other birds, small mammals, and invertebrates, and (2) create and maintain sap wells, a temporary nutritional resource available to a variety of secondary consumers. Most previous reports of secondary sap consumption relied on human observers and were based on either brief or incidental observations. However, modern technology can greatly enhance observational techniques and provide additional insights into the functional, community-level importance of sap wells. We used visual surveys, camera traps, and environmental DNA (eDNA) to identify secondary consumers of sap from wells created by red-naped ( Sphyrapicus nuchalis ) and Williamson's ( S. thyroideus ) sapsuckers among three functional groups of shrubs and trees in south-central Colorado: shrub willows ( Salix spp.), Rocky Mountain maple ( Acer glabrum ), and conifer trees (Pinopsida). Camera traps and eDNA revealed additional sap-well visitors not identified from direct observations. Camera traps were effective for detecting nocturnal sap-well visitors such as small rodents as well as occasional diurnal visitors. Environmental DNA analyses corroborated findings from other methods and identified four additional taxa as possible sap consumers. The physiology of sap-well visitors, such as the ability to taste and assimilate compounds within sap, may aid in determining consumption versus contact when evaluating the results of eDNA analyses. Total vertebrate taxa detected using all 3 methods included 17 bird taxa in 10 families within 3 orders and 8 mammal taxa in 6 families within 4 orders. Shrub-willow sap wells attracted the most diverse vertebrate taxa (23), followed by Rocky Mountain maple (13) and conifer trees (10). Invertebrates in 13 families within 3 orders were observed feeding from sap wells during visual surveys. Because many secondary sap consumers perform ecological services such as pollination, seed dispersal, and pest control, the methods described here may aid in elucidating the importance of sap-well creators in supporting biodiversity and ecosystem functioning.

Colorado↗
USGS2019

Left out in the rain: Comparing productivity of two associated species exposes a leak in the umbrella species concept

Multi-species approaches to wildlife management have become commonplace and purport to benefit entire biological communities. These strategies aim to manage different, often taxonomically distant species under a single regime based on shared habitat associations and/or co-occurrence in the landscape. We tested the efficacy of multi-species management in the context of creating and maintaining early-successional forest cover types using two species of migratory birds that breed in eastern North America and are each the focus of intensive, concurrent, and overlapping management. American woodcock ( Scolopax minor ) and golden-winged warblers ( Vermivora chrysoptera ) breed in similar diverse-forest landscapes. Each species purportedly benefits from management for the other species and both are often used as flagship species for the creation of young forest and the conservation of associated avian communities. However, the landscape-species relationships that drive reproductive success and population stability in these species have not been explicitly compared. Here, we use previously published spatially-explicit models of productivity (the number of juveniles raised to a biologically significant milestone) to identify the relationship(s) between productivity of American woodcock and golden-winged warblers across a shared landscape. We found productivity to be negatively associated between these species on the same landscape at all spatial scales we modelled (1 m 2 –100 ha). Our results suggest that, with regards to productivity, American woodcock and golden-winged warblers have opposing relationships with the composition of the landscapes in which they coexist and therefore should not be assumed to benefit similarly from any individual management action at any relevant spatial scale.

Biological Conservation↗
USGS2010

Effects of lipid extraction on stable isotope ratios in avian egg yolk: Is arithmetic correction a reliable alternative?

Many studies of nutrient allocation to egg production in birds use stable isotope ratios of egg yolk to identify the origin of nutrients. Dry egg yolk contains >50% lipids, which are known to be depleted in 13 C. Currently, researchers remove lipids from egg yolk using a chemical lipid-extraction procedure before analyzing the isotopic composition of protein in egg yolk. We examined the effects of chemical lipid extraction on ?? 13 C, ?? 15 N, and ?? 34 S of avian egg yolk and explored the utility of an arithmetic lipid correction model to adjust whole yolk ?? 13 C for lipid content. We analyzed the dried yolk of 15 captive Spectacled Eider (Somateriafischeri) and 20 wild King Eider (S. spectabilis) eggs, both as whole yolk and after lipid extraction with a 2:1 chloroform:methanol solution. We found that chemical lipid extraction leads to an increase of (mean ?? SD) 3.3 ?? 1.1% in ?? 13 C, 1.1 ?? 0.5% in ?? 15 N, and 2.3 ?? 1.1% in ?? 34 S. Arithmetic lipid correction provided accurate values for lipid-extracted S13C in captive Spectacled Eiders fed on a homogeneous high-quality diet. However, arithmetic lipid correction was unreliable for wild King Eiders, likely because of their differential incorporation of macronutrients from isotopically distinct environments during migration. For that reason, we caution against applying arithmetic lipid correction to the whole yolk ?? 13 C of migratory birds, because these methods assume that all egg macronutrients are derived from the same dietary sources. ?? 2010 The American Ornithologists' Union.

The Auk↗
USGS1975

Death feigning by ducks in response to predation by red foxes (Vulpes fulva)

Predation by captive red foxes ( Vulpes fulva ) on approximately 50 ducks comprised of five species was observed in tests conducted at the Northern Prairie Wildlife Research Center, Jamestown, North Dakota. Most ducks were attacked from a rear or lateral position and seized in the cervical or thoracic region. All birds became immobile (death-feigned) immediately when seized and with few exceptions remained motionless during prey-handling and for varying lengths of time thereafter. Initial death feints lasted from 20 sec to 14 min. Recovery was delayed by tactile, visual and, possibly, auditory cues from the foxes. Death-feigning birds appeared alert and often took advantage of escape opportunities. Twenty-nine birds survived initial capture and handling by the foxes. Naive foxes were wary of ducks during initial confrontations, but experienced foxes showed little hesitation in attacking them. After capture, most ducks were taken alive to lay-down sites where they were mouthed and often killed. Then the ducks were usually cached or taken to dens or pups. Several birds were cached alive. Red foxes appear to have adapted to the escape of death-feigning ducks by learning to kill some birds soon after capture and by the evolution of an appendage-severing behavior. Death feigning appears to be a highly developed antipredator behavior of ducks that facilitates the escape of some birds after capture by red foxes.

American Midland Naturalist↗
USGS1984

Avian models for toxicity testing

The use of birds as test models in experimental and environmental toxicology as related to health effects is reviewed, and an overview of descriptive tests routinely used in wildlife toxicology is provided. Toxicologic research on birds may be applicable to human health both directly by their use as models for mechanistic and descriptive studies and indirectly as monitors of environmental quality. Topics include the use of birds as models for study of teratogenesis and embryotoxicity, neurotoxicity, behavior, trends of environmental pollution, and for use in predictive wildlife toxicology. Uses of domestic and wild-captured birds are discussed.

Journal of the American College of Toxicology↗
USGS2015

Archiving California’s historical duck nesting data

The U.S. Geological Survey (USGS), in partnership with the California Waterfowl Association (CWA) and other organizations, have compiled large datasets on the nesting ecology and management of dabbling ducks and associated upland nesting birds (Northern Harriers [ Circus cyaneus ], Short-eared Owls [ Asio flammeus ], Ring-necked Pheasants [ Phasianus colchicus ], and American Bitterns [ Botaurus lentiginosus ]) throughout California on Federal Refuges, State Wildlife Areas, and private lands, some participating in State and Federal habitat programs. These datasets encompass several long-term monitoring programs at multiple sites throughout California, and include data from more than 26,000 nests and span nearly 30 years. These historical datasets represent some of the longest term datasets on nesting ducks in North America, if not the world. They are extremely valuable for ongoing waterfowl management and habitat conservation efforts in California, as well as throughout the world. However, without organization and electronic access, these data are an untapped resource and are not being used to the full extent possible. Prior to this project, these datasets were scattered among various agencies and organizations, and original paper nest cards were being stored in cardboard boxes in attics and storage containers that were not suitable for long-term archival storage. In addition, most of these data had not been entered into a computerized database and thus were at high risk for permanent data loss. To protect this irreplaceable dataset, we submitted a series of proposals to obtain funds to complete this data archival project over the past 5 years. The Central Valley Joint Venture, USGS Data Rescue Program, and USGS Ecosystems Mission Area funded this data archival project. In addition, we leveraged other USGS projects on nesting shorebirds, songbirds, and seabirds to use further resources to more fully develop the nest database structure for use on nesting waterfowl. Specifically, this large dataset on ducks was archived by USGS, but the dataset is owned and managed by a consortium of organizations. Therefore, any access and use of this data must occur through the principal investigators, who contributed data and resources to this archival project, as detailed in section, &ldquo;Data Availability.&rdquo; With the conclusion of this project, most duck nest data have been entered, but all nest-captured hen data and other breeding waterfowl data that were outside the scope of this project have still not been entered and electronically archived. Maintaining an up-to-date archive will require additional resources to archive and enter the new duck nest data each year in an iterative process. Further, data proofing should be conducted whenever possible, and also should be considered an iterative process as there was sometimes missing data that could not be filled in without more direct knowledge of specific projects. Despite these disclaimers, this duck data archive represents a massive and useful dataset to inform future research and management questions.

California↗
USGS2014

The spring migration of adult North American Ospreys

Most North American Ospreys ( Pandion haliaetus ) are migratory, breeding in northern latitudes and migrating long distances to and from their wintering grounds in the tropics. Although fall migration patterns of North American Ospreys have been described and studied, very little has been published about the spring migration of these birds. We used satellite telemetry to: (1) determine the characteristics (timing, duration, migratory routes) of spring migrations of Ospreys; (2) determine if differences in spring migration patterns existed between sexes and among three breeding populations (east coast, midwestern, and western); and (3) compare consecutive fall and spring migrations of individual Ospreys. The median dates for departure from the wintering grounds and arrival on the breeding grounds did not differ significantly between adult male and female Ospreys. Compared to their fall migrations, all male and all east coast Ospreys spent fewer days on migration, fewer days in stopover periods along the migration route, traveled shorter distances overall, and traveled farther (on average) each day during spring. In contrast, fall and spring migration characteristics of all female and western Ospreys were similar. Our findings suggest that, although sex and breeding location might influence the spring migration strategy used by individual Ospreys, both males and females minimize the time spent on migration to ensure a timely arrival on the breeding grounds to establish or defend a nesting territory.

Journal of Raptor Research↗
USGS1981

Pharmocokinetics of cephalothin and cephalexin in selected avian species

Plasma concentrations and the biological half-lives of cephalothin and cephalexin in avian species of a variety of body sizes and metabolic rates were studied. The species chosen were eastern bobwhite quail (Colinus v virginianus), pigeons (Columba livia), hybrid rosybill ducks (Netta sp), greater sandhill cranes (Grus canadensis tabida), and emus (Dromiceius novaehollandiae). In the 1st phase of the study, cephalothin sodium was given IM in a dose of 100 mg/kg of body weight. Plasma concentrations reached peak (av 18 micrograms/ml) at 0.5 hour and were measurable 2.5 to 5.5 hours after drug administration. The biological half-life of cephalothin was 16 to 54 minutes; the half-life varied directly with increased species body weight, with the exception of the ducks studied. In the 2nd phase, cephalexin monohydrate was given orally in doses of 25, 35, and 50 mg/kg of body weight. Plasma concentrations reached peak (av 20 micrograms/ml) at 0.5 to 1 hour and were measurable 2.5 to 5.5 hours after drug administration. The biological half-life of cephalexin was 36 to 126 minutes. In the 3rd phase, differences in plasma concentrations and the half-lives of cephalexin between fed quail and fasted quail were insignificant. Dosage regimens for cephalothin of 100 mg/kg 4 times a day and for cephalexin of 35 to 50 mg/kg 4 times a day would be expected to establish and maintain therapeutic plasma concentrations in large birds (pigeons, cranes, and emus). These same doses, administered every 2 to 3 hours, would be expected to establish and maintain therapeutic plasma concentrations in smaller birds (quail, ducks).

American Journal of Veterinary Research↗
USGS2002

Role of selenium toxicity and oxidative stress in aquatic birds

Adverse effects of selenium (Se) in wild aquatic birds have been documented as a consequence of pollution of the aquatic environment by subsurface agricultural drainwater and other sources. These effects include mortality, impaired reproduction with teratogenesis, reduced growth, histopathological lesions and alterations in hepatic glutathione metabolism. A review is provided, relating adverse biological effects of Se in aquatic birds to altered glutathione metabolism and oxidative stress. Laboratory studies, mainly with an organic form of Se, selenomethionine, have revealed oxidative stress in different stages of the mallard (Anas platyrhynchos) life cycle. As dietary and tissue concentrations of Se increase, increases in plasma and hepatic GSH peroxidase activities occur, followed by dose-dependent increases in the ratio of hepatic oxidized to reduced glutathione (GSSG:GSH) and ultimately hepatic lipid peroxidation measured as an increase in thiobarbituric acid reactive substances (TBARS). One or more of these oxidative effects were associated with teratogenesis (4.6 ppm wet weight Se in eggs), reduced growth in ducklings (15 ppm Se in liver), diminished immune function (5 ppm Se in liver) and histopathological lesions (29 ppm Se in liver) in adults. Manifestations of Serelated effects on glutathione metabolism were also apparent in field studies in seven species of aquatic birds. Reduced growth and possibly immune function but increased liver:body weight and hepatic GSSG:GSH ratios were apparent in American avocet (Recurvirostra americana) hatchlings from eggs containing 9 ppm Se. In blacknecked stilts (Himantopus mexicanus), which contained somewhat lower Se concentrations, a decrease in hepatic GSH was apparent with few other effects. In adult American coots (Fulica americana), signs of Se toxicosis included emaciation, abnormal feather loss and histopathological lesions. Mean liver concentrations of 28 ppm Se (ww) in the coots were associated with elevated hepatic GSH peroxidase, depletion of hepatic protein bound thiols and total thiols, but a small increase in GSH. Diving ducks in the San Francisco Bay area exhibited a positive correlation between hepatic Se concentration and GSH peroxidase activity (r=0.63, P<0.05), but a negative correlation between hepatic Se and GSH concentration (r=0.740, P<0.05). In willets (Catoptrophorus semipalmatus) from the San Diego area, positive correlations occurred between hepatic Se concentration and GSSG (r=0.70, P<0.001), GSSG:GSH ratio, and TBARS. In emperor geese (Chen canagica) from western Alaska, blood levels of up to 9.4 ppm occurred and were associated with increased plasma GSH peroxidase activity (r=0.62, P<0.001), but with decreased plasma GSSG reductase activity. When evaluating Se toxicity, interactive nutritional factors, including other elements and dietary protein, should also be taken into consideration. Further studies are needed to examine the relationship between different forms of environmentally occurring selenium, arsenic and mercury on reproduction, hepatotoxicity and immune function of aquatic birds. Further selenium nutritional interaction studies may also help to illucidate the mechanism of selenium induced teratogenesis, by optimizing GSH and other antioxidant defense mechanisms in a manner that would stabilize or raise the cell's threshold for susceptibility to toxic attack from excess selenium. It is concluded that Se-related manifestations of oxidative stress may serve as useful bioindicators of Se exposure and toxicity in wild aquatic birds.

Aquatic Toxicology↗
USGS1995

Dicofol and DDT residues in lizard carcasses and bird eggs from Texas, Florida, and California

Dicofol is an organochlorine agricultural pesticide used to control mites. The principal commercial dicofol product is known as Kelthane TM. More than 70% of dicofol product (about 3 million Ib or 1.4 million kg) sold annually in the U.S. is applied in California, Arizona, Texas, and Florida. Florida citrus and California cotton receive more than half the total (Clark 1990). In laboratory studies, dicofol, which is structurally similar to DDT, had adverse impacts on reproduction in fish (deformed larvae, delayed hatching), birds (reduced eggshell thickness, reduced hatchability), and mammals (reduced insemination rate, reduced pregnancy rate, failure to produce young) (see Clark 1990 for review). Overall, the reproduction of birds seems less sensitive to dicofol than to DDE. However, in birds, dietary concentrations of dicofol between 1 and 10 µg/g (wet weight) fed to captive adult females caused such problems as eggshell thinning, reduced hatching success, or reduced fertility in American kestrels ( Falco sparverius ) (Fry et al. 1988, Clark et al. 1990) and eastern screech-owls ( Otus asio ) (Wiemeyer et al. 1989). In spite of these laboratory findings, there have been no intensive field investigations of possible reproductive effects of dicofol on wild birds. Such studies must wait until field residue data are sufficient to identify populations with high exposure. If dicofol accumulates in birds in the field and heavily exposed populations can be identified, then their reproduction can be studied. Residues have not been reported from reptiles. Analytical screening of wildlife tissue samples for organochlorine chemicals only rarely includes dicofol, and this may explain why the relative hazard of dicofol to wildlife populations is poorly known.

California, Florida, Texas↗
USGS1998

The seventy-fourth Christmas bird count. 315. Southern Dorchester County, Md

Because limited information is available regarding preferences for nocturnal habitat during winter, we studied use of nocturnal habitats by American woodcock (Scolopax minor) wintering in the Georgia Piedmont (1994-95). During the evening crepuscular period, woodcock on the wintering grounds move from forested to field habitats, presumably to feed, conduct courtship displays, roost, and avoid predators. We conducted crepuscular flight surveys and tracked radio-marked woodcock to compare the use of fields of different sizes (<5.5 ha, 5.540.0 ha, >40.0 ha) and types (seed tree-clearcuts, fallow-old fields, hayfields, pastures). Fields > 5.5 ha were used more frequently than fields <5.5 ha (P < 0.001). Seed tree-clearcuts and fallow-old fields were more frequently used than pastures (P = 0.003). Woodcock also most frequently used fields with greater foliage volume at 0.82.0 m in height and a high percentage of bare soil (P < 0.001). Nocturnal use of fields or forests by radio-marked woodcock did not differ among age or sex classes. However, females moved an average of 230 + 32.1 m between diurnal and nocturnal locations while males moved 525 + 53.1 m ( P = 0.085). Movements differed among moon phases (P < 0.003), ranging from 579 + 79.6 m during the new moon to 213 + 50.5 m during the full moon. To manage habitat on the wintering grounds, seed tree-clearcuts and fallow-old fields should be created or maintained near preferred diurnal habitats.

Journal of Wildlife Management↗