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Results for “Canadian Field Naturalist”

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At least 55 records · Page 3Linked to original sources
USGS1987

Responses of three prairie ground squirrel species, Spermophilus franklinii, S. richardsonii, and S. tridecemlineatus, to duck eggs

Franklin's Ground Squirrels (Spermophilus franklinii) preyed on eggs in 29 of 30 tests in which they were exposed to two Mallard (Anas platyrhynchos) or two Blue-winged Teal (A. discors) eggs and their discovery of eggs was confirmed. No Richardson's (S. richardsonii) or Thirteen-lined (S. tridecemlineatus) ground squirrels preyed on eggs in 104 and 54 similar tests, respectively. Franklin's Ground Squirrels exposed to clutches of six duck eggs placed in simulated nests preyed on all such clutches. Predation on simulated nests began soon after eggs were discovered, but predation of all eggs often took more than one day to complete.

Canadian Field-Naturalist↗
USGS1982

Recurrence, mortality, and dispersal of prairie striped skunks, Mephitis mephitis, and implications to rabies epizootiology

Detailed study of radio-equipped individuals of the Striped Skunk (Mephitis mephitis) in a North Dakota population provided insight into possible mechanisms for spread of rabies during spring and summer. Annual recurrence rates of 138 skunks marked on a study area averaged 11% for adult males, 43% for adult females and 9% for kits. Population changes were from mortality (including rabies) and dispersal. Five instances of adult dispersal (four by males) were recorded; maximum straight-line distance was 119 km. Some males initiated dispersal in spring. Communal denning by adults occurred rarely after whelping began but resulted in intraspecific conflict. Evidence of intraspecific and interspecific strife leading to kit mortality and some adult mortality was found at dens of 9 of 40 litters studied.

Canadian Field-Naturalist↗
USGS1987

Nongame bird communities on managed grasslands in North Dakota

Grazed native prairie, unmanipulated native prairie, and planted alfalfa-wheatgrass habitats each supported prairie bird species unique to that habitat type. Comparisons of the three habitats, using community coefficients and overlap indices, showed that grazed and alfalfa-wheatgrass habitats supported the most dissimilar or unique bird communities. All three habitat types, or habitats with similar vegetation structure, must be incorporated in grassland management plans to support all members of the mixed-grass prairie bird community.

North Dakota↗
USGS1981

Grazing intensity effects on the breeding avifauna of North Dakota native grasslands

A breeding bird census and plant survey was conducted on 180 samples of lightly, moderately, and heavily grazed and hayed native grasslands in North Dakota in 1974. The ten most important cover plants on each of eight major physiographic landforms in three of the four regions (the Agassiz Lake Plain excluded) overlapped so extensively that only 19 species were involved: 13 grasses or sedges, four forbs, one shrub, and one clubmoss. Bird densities were generally highest in (i) regions and landforms containing numerous natural basin wetlands, (ii) flatter, glaciated landforms containing more fertile soils, and (iii) landforms of greater relief and high habitat heterogeneity. Avian species richness tended to decrease with increased grazing intensity, but total bird density increased due to higher populations of a few species, and hayland that had been mowed and raked during the previous growing season was highly attractive to some species.

Canadian Field-Naturalist↗
USGS1981

Observations on black-crowned night heron breeding success in a North Dakota marsh

Storms and mammalian predation severely reduced production in a Black-crowned Night Heron (Nycticorax nycticorax) colony in two years and drought prevented nesting in two other years from 1976 to 1980. Maximum estimated production was 2.2 young per pair in 1978, the only year production was sufficient to maintain the population.

Canadian Field-Naturalist↗
USGS1975

Effects of agricultural burning on nesting waterfowl

Agricultural burning in an intensively farmed region within Manitoba's pothole district is shown to affect the nesting activities of ground-nesting ducks. All species, except Blue-winged Teal (Anas discors), preferred unburned nest cover, although success was higher in burned areas, where predators may have exerted less influence. Attitudes of farmers, burning chronology, and nest destruction by fires are also reported.

Canadian Field-Naturalist↗
USGS2001

Standing over and hugging in wild wolves

During six summers, I observed standing over (SO) and hugging in a pack of wild Wolves (Canis lupus) habituated to me. In SO, one Wolf positions its groin above a recumbent Wolf's nose. I observed SO among all yearling and older Wolves for 1-180 seconds ( X? = 69 ¨± 46 S.D.; N = 16 ). SO appeared to be primarily female-oriented and may inform each Wolf of the reproductive status of the other. I observed hugging five times and only during years when food competition was minimal.

Canadian Field-Naturalist↗
USGS2000

Leadership in wolf, Canis lupus, packs

I examine leadership in Wolf (Canis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed.

Canadian Field-Naturalist↗
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↗
USGS2002

Differential use of a wolf, Canis lupus, pack territory edge and core

Based on 418 radio-locations of a Minnesota wolf pack, wolves were found at significantly fewer locations per area in the outer 2 km of the territory than in the core. This finding supports an hypothesis that buffer zones exist between pack territories and may explain why prey survive longer there.

Canadian Field-Naturalist↗
USGS2002

Records of northern mockingbird, Mimus polyglottos, occurrences in North Dakota during the Twentieth Century

The Northern Mockingbird (Mimus polyglottos) is a common bird in the southern United States that has been expanding its breeding range into the northern United States and southern Canada. During the twentieth century, there were 128 reports of Northern Mockingbird occurrences in North Dakota, including 106 reports during the breeding season (15 April to 31 August) and 22 during the nonbreeding season (1 September to 14 April). The species has been largely absent from North Dakota from January through mid-April. Prior to the 1930s, there was only one record (1916) of the Northern Mockingbird in the state. Observations of Northern Mockingbirds in North Dakota increased markedly between the 1930s and 1990s. On average, there were 0.3 reports of mockingbirds per year in 1931-1940, 0.6 in 1941-1950, 1.1 in 1951-1960, 1.6 in 1961-1970, 2.4 in 1971-1980, 2.3 in 1981-1990, and 4.5 in 1991-2000. The species has been observed in North Dakota nearly annually since 1958. At least six reports during the twentieth century included evidence of nesting (nests or dependent young). Based on mockingbird records during the twentieth century, we designate the current status of the Northern Mockingbird in North Dakota as a rare spring migrant, rare summer visitant, casual nester, and a casual fall and winter visitant.

Canadian Field-Naturalist↗
USGS1986

Effects of shrub coverages on birds of North Dakota mixed-grass prairies

We studied the distribution and density of passerine birds in relation to Wolfberry (Symphoricarpos occidentalis) and Silverberry (Elaeagnus commutata) shrub coverages on mixed-grass prairies of central North Dakota. Birds were counted along shrubby and shrubless transects during the 1982 breeding season. Species richness and total density of birds were greater on shrubby transects. Five species were more abundant on shrubby transects. Availability of woody nesting substrates best explained differences in bird species abundances. Differences in shrub coverages between transects were probably the result of different land-use practices. Land management practices which modify shrub coverages can alter the composition of passerine bird communities.

North Dakota↗
USGS1999

Killing of a muskox, Ovibos moschatus, by two wolves, Canis lupis, and subsequent caching

The killing of a cow Muskox ( Ovibos moschatus ) by two Wolves ( Canis lupus ) in 5 minutes during summer on Ellesmere Island is described. After two of the four feedings observed, one Wolf cached a leg and regurgitated food as far as 2.3 km away and probably farther. The implications of this behavior for deriving food-consumption estimates are discussed.

Canadian Field-Naturalist↗