Geology topics
Publications and source records attributed to D.G. McAuley.
The authors investigated the survival of breeding male American woodcock in Washington County, Maine. A total of 150 birds were radio-arked during 1987-1989 and relationships were evaluated between survival, body mass, predation, weather, and habitat use. Survival varied from 0.690 (1989) to 0.924 (1988), with a 3-year mean (95% confidence interval) of 0.789 (0.693-0.885)
We used radiotelemetry to determine habitat use and movements of 38 female juvenile American black ducks (Anas rubripes) on the north shore of the St. Lawrence estuary, Quebec, from 28 August to 15 November 1991. Ducks separated into three groups based on habitat use: inland, estuarine, and those using a mixture of habitats. Ducks using mixed habitats used the greatest variety of habitat types, flew the greatest distances and most often between night roosts and day foraging areas, and were unlikely to be shot. The mean distance flown between night-use and day-use areas for all ducks increased nearly 50% after the hunting season began (overall mean = 6104 m, range 1500 - 26384 m). Mean home range size was 27.6 t 6.5 (SE) km2. Ducks exhibited stronger fidelity to wetlands used at night than to those used during the day. Ducks that were shot spent a high percentage of their time on the estuary (90.1 t 7.4 %) and exhibited high fidelity to a day-use area before the hunting season (73 t 7.3 %).
We critiqued previous work on the biology and management of the American woodcock (Scolopax minor) on the breeding grounds. We determined that little is known about habitat variables and weather extremes that may limit the population. Most investigators who attempted to define habitat requirements of the woodcock used inadequate sample sizes, limited the duration of their studies, did not account for effects of weather, or failed to adequately measure habitat variables. Furthermore, the effects of hunting on local or regional populations has never been adequately studied. We concluded that obtaining data to understand the biology of the woodcock and the effects of hunting is essential before managers can reverse the long-term decline of woodcock numbers.
We describe methods for the study of the American woodcock (Scolopax minor) at the Moosehorn National Wildlife Refuge. Described are techniques for the capture of particular age-sex cohorts during different times of the year, the aging and sexing, the evaluation of habitat components, and the estimation of population size. We describe successful and tried but rejected techniques with radio-telemetry for the study of survival and habitat use.
During spring 1986-89, we equipped 175 male and 89 female American woodcocks (Scolopax minor) with radio transmitters. Radio-marking had little effect on behavior; within 1 day of marking, 37 of 64 (58%) displaying males were dominant and within 7 days, 138 of 157 (88%) were dominant. All females marked before nesting proceeded to nest, and marked females with broods remained with broods after release. Dominance of males declined from 73% in April to 69% in May and to 26% in June as breeding activity waned. In all years, after-second-year (ASY) males were dominant more often than second-year (SY) males (67.5% vs. 58.9%). ;Most males displayed at more than one (range = 2-12) site. Distances that males moved between the primary singing ground and subsequent singing grounds averaged 775 m in all years and ranged from 618 m (1986) to 966 m (1988). Females visited males at singing grounds throughout the breeding cycle; some females visited more than one site. During prenesting, females remained in daytime covers during the crepuscular period (55%), flew to different feeding covers (22%), visited singing grounds (14%), or flew from daytime covers to unknown locations (9%). During nesting, females left nests during the crepuscular period (72%) and moved to singing grounds (5%), to feeding areas (59%), and to undetermined locations (7%). Females with broods remained with their broods during the crepuscular period (62%), flew to feeding areas (30%), visited singing grounds (1%), or flew to undetermined locations (6%). The woodcock mating system is similar to a resource-based polygyny. Males compete for singing grounds near high-quality nesting areas. The fitness of males is expressed by dominance at more than one singing ground. Woodcocks are not monogamous; females may visit more than three different males during a single courtship period but do not visit males regularly. Most females leave nests during the crepuscular period to feed in a different cover.
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We examined the use of 87 palustrine and lacustrine wetlands by nongame water birds in central and eastern Maine using 3,527 h of observation (1,501 visits) made during April-August, 1977-85. Wetlands used by 15 species of water birds were distinguished from those not used, according to 20 habitat features. The species were the common loon (Gavia immer) , pied-billed grebe (Podilymbus podiceps), double-crested cormorant (Phalacrocorax auritus), American bittern (Botaurus lentiginosus), great blue heron (Ardea herodias), green-backed heron (Butorides striatus), osprey (Pandion haliaetus), bald eagle (Haliaeetus leucocephalus), northern harrier (Circus cyaneus), Virgima rail (Rallus limicola), sora (Porzana carolina), spotted sandpiper (Actitis macularia), common snipe (Gallinago gallinago), herring gull (Larus argentatus), and belted kingfisher (Ceryle alcyon). Predictive models of habitat use were developed for each species. Water birds were classified by similarity of habitats used, and species use was contrasted by wetland type. Smaller, isolated wetlands were used by fewer (P < 0.05) species than larger wetlands in complexes; many species had large area-requirements (pied-billed grebe, common loon, herring gull, double-crested cormorant, bald eagle) or preferred to use wetlands near other wetlands (common loon, herring gull, great blue heron, spotted sandpiper, osprey, bald eagle). Wetland area contributed more to overall variation in species richness on wetlands than wetland isolation, although on small wetlands (<3.6 ha) isolation was a better predictor of species richness than wetland area. Wetlands with intermediate amounts (33-66%) of emergent vegetation supported more species (P< 0.05) than closed (>66%) or open (<33%) wetlands. Low pH typified wetlands used by large-bodied piscivores (common loon, cormorant, osprey). Other water birds were associated with more densely vegetated, chemically buffered wetlands. Habitat features associated with wetland use by each waterbird species are reported, as are numerical responses of waterbird populations to wetland features and estimates of annual variation in habitat occupancy. Lacustrine wetlands supported a distinct, low diversity community of water birds, including most fish-eating species. Waterbird diversity at forested palustrine wetlands was intermediate between lacustrine communities and more species-rich assemblages at palustrine emergent and scrub-shrub wetlands. Regional variation in wetland characteristics and water bird use was associated with surficial geology, soils, and management practices. Management for nongame water birds in Maine should consider providing emergent and aquatic-bed vegetation with variable cover-to-water ratios, accommodating species-specific habitat needs, focusing on species of restricted distribution and low abundance, and maintaining wetland complexes. Bird use and habitat information from 87 wetlands and models of habitat selection for each species are provided in appendixes.
We monitored the movements of 97 female and 15 male juvenile American black ducks (Anas rubripes) in the vicinity of Moosehorn National Wildlife Refuge in eastern Maine and southwestern New Brunswick from September through mid- December, 1985-1987.. Movements were described by estimating home ranges and radial movements from the primary roost marsh. Overall home range sizes averaged 4987 ha (range 54 - 28 070 ha), and maximum distances moved from the roost averaged 9.9 km (range 0.9-42.8 km). Home ranges were linear (linearity index 2.8), and home range area and distance of movements from the roost both increased monthly. Ducks that used >15 % riverine habitat had larger home ranges and moved greater distances from the roost than ducks using <15% riverine wetlands. Movements did not differ between ducks usually alone and those usually in flocks. Juvenile black ducks moved in small flocks and were often alone (34% of 355 observations). Most ducks showed fidelity to one roost-marsh complex from September until migration in late November. Daily and seasonal movement patterns were similar to those predicted for refuging systems.
The American Woodcock ( Scolopax minor ) is one of the earliest ground-nesting birds in the northeastern United States. In Maine, nesting begins in early April when temperatures can drop below freezing and significant snowfall can accumulate. Nests are usually in open woods, where eggs are laid on the ground in a shallow depression (Pettingill 1936, Mendall and Aldous 1943, Sheldon 1967). Peak hatching occurs in early May (Dwyer et al. 1982), when temperatures are cool and precipitation is common. Woodcock chicks are dependent on the female for most of their food for at least seven days after hatching (Gregg 1984). During cool, wet weather, chicks require constant brooding by females; prolonged periods of inclement weather may lead to substantial mortality of chicks (Dwyer et al. 1988).
The effects of small clearcuts (1 - 8 ha) on avian communities in the forest of eastern Maine were studied using point counts during spring 1978 - 1981. Surveys were conducted in uncut (control) and clear-cut (treatment) plots in three stand types: conifer, hardwood, and mixed growth. We used a mark-recapture model and its associated jackknife species richness estimator (N), as an indicator of avian community structure. Increases in estimated richness (N) and Shannon - Weaver diversity (H') were noted in the treated hardwood and mixed growth, but not in the conifer stands. Seventeen avian species increased in relative abundance, whereas two species declined. Stand treatment was associated with important changes in bird species composition. Increased habitat patchiness and the creation of forest edge are hypothesized as causes for the greater estimates of richness and diversity.
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Selected aspects of the nesting biology of Ring-necked Ducks in east-central Maine were studied during 1983-1985 and compared to previous studies. Nesting chronology, clutch size, and hatching success were similar to results reported from previous studies, but nest success was 32-42% lower. Thirty-eight percent of the nests were successful; % of the eggs in successful nests hatched. Among unsuccessful nests, predation and flooding caused most failures.
An improved method of automatically monitoring nest attentiveness was designed and tested using radio-equipped American Woodcock (Scolopax minor). Shielded coaxial cable (RG-58) was extended from a receiver and placed 30 cm above the nest, with a 3.8 cm section of the inner wire exposed. Presence, absence, and activity of birds within 10.1 ? 5.2 m (SD) of the nest were clearly indicated on a Rustrak recorder while extraneous signal interference was minimized.
A population of American woodcock (Scolopax minor) was studied on a 3,401-ha area of the Moosehorn National Wildlife Refuge in northeastern Maine from 1976 through 1985. During 1976-83, from 4 to 64 clearcuts were created each year, opening up large contiguous blocks of forest. A combination of mist nets, ground traps, nightlighting techniques, and trained dogs were used to capture and band 1,884 birds during the first 5 years. Capture and recapture data (totaling 3,009 observations) were used with both demographically closed and open population models to estimate population size and, for open population models, summer survival. Flying young, especially young males, represented the greatest proportion of all captures; analysis showed that young males were more prone to capture than young females. Male courtship began about 24 March each year, usually when there was still snow in wooded areas. Males ~2 years old dominated singing grounds during April each year, but this situation changed and first-year males dominated singing grounds in May. Singing males shifted from older established singing grounds to new clearcuts soon after we initiated forest management. Many males were subdominant at singing grounds despite an abundance of unoccupied openings. Three hundred adult females were captured and, except for 1978, the majority were ~2 years old. The year in which female homing rate was lowest(1979) was preceded by the year with the largest number of l-year-old brood female captures and a summer drought. Summer survival of young was lowest in 1978 and was attributed to summer drought. The year 1979 had an abnormally cool and wet spring, and was the poorest for production of young. Capture ratios of young-to-adult females obtained by nightlighting could be used to predict production on our study area. Closed population model estimates did not seem to fit either young or adult data sets well. Instead, a partially open capture-recapture model that allowed death but no immigration seemed to fit best. Only the number of males in the population changed significantly during the study. An increase from 88 males in 1976 to 156 in 1980 was attributed to habitat management. Singingmale surveys on our area detected little change in the number of singing males, but our independent population estimates from mark-recapture data showed a larger total male population by 1980. Annual density estimates for all age and sex classes ranged from 19 to 25 birds/l00 ha. A hypothesis on the breeding system of the American woodcock is presented as well as a discussion of management implications, including the importance of creating high-quality habitat on private lands.
We designed a bait trap for wintering Canvasbacks (Aythya valisineria) that has proven more effective than conventional funnel or slot entrance traps for diving ducks. The unique feature of this trap is the corral entrance that presents unimpaired access to the bait and thus ease of entrance to the trap. Catches of 50-75 ducks have been made in a matter of minutes at prebaited sites.
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Mallard (Anas platyrhynchos) pairs (2-4) and broods (1-2) have occurred sporadically each year during recent (1977-86) waterfowl investigations in Maine. State-wide brood counts (1956-1986) for 36 wetlands in Maine depict an average increase of 1-3 mallard broods. Broods occurred mostly on man-made impoundments. Numbers of mallards captured during banding (as a percentage of combined mallards, American black ducks [Anas rubripes] and hybrids) have increased from 4.3 to 28.7% in southern Maine, 3.6 to 9.1% in central Maine, and 0.5 to 2.6% in eastern Maine during the last 3 or 4 decades. The percentage of mallards captured in northern Maine in the last decade averaged 11.8%. The occurrence of mallard x black duck hybrids handled during pre-season banding has been variable among decades, but < 2.0% for all the banding sites. Mixed-species pairs, usually a male mallard and a female black duck have been recorded. . Survival of mallard ducklings to fledging (4/brood) approximates that of black ducks, but our sample of broods (N=7) was small. Paired, male, black ducks aggressively drove away intruding mallards and conspecifics. The role of mallard releases and small marsh construction is implicated in the establishment of the 657 mallard pairs estimated as breeding in Maine.
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