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Results for “Canadian Field Naturalist”

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At least 91 records · Page 5Linked to original sources
USGS1996

Malocclusion in the jaws of captive bred Arctic wolves

Similar abnormalities in the skulls of captive Arctic Wolves (Canis lupus arctos) and a wild Arctic wolf found dead on Ellesmere Island, Canada, in 1986 are described. The malocclusion is likely to be recessively inherited and would be expressed more frequently in association with increased levels of inbreeding. A re-shaping of the skulls may have occurred due to the effects of the malocclusive trait. The Ellesmere skull was short and wide in comparison to the captive skulls which were long and narrow. The focus of effect was in a foreshortening of the rostrum and the resulting shortened toothrow.

Canadian Field-Naturalist↗
USGS1996

Denning behaviour of non-gravid wolves, Canis lupus

Wild wolves (Canis lupus) that had produced pups in earlier years but were not currently pregnant, and ovariectomized captive wolves, dug dens during and after the whelping season even though they produced no pups. These observations suggest that den digging is not a function of pregnancy or of ovarian estrogen or progesterone. We hypothesize that increasing prolactin in spring elicits or mediates den-digging behavior.

Canadian Field-Naturalist↗
USGS1997

An example of endurance in an old wolf, Canis lupus

An 11 to 13-year-old Arctic Wolf (Canis lupus arctos) was observed chasing a young Arctic Hare (Lepus arcticus) for 6 to 7 minutes and catching it. This provides an example of the degree of endurance of which an old wolf is capable.

Canadian Field-Naturalist↗
USGS1995

Summer movements and behavior of an Arctic wolf, Canis lupus, pack without pups

A pupless arctic Wolf pack (two adults, three yearlings) studied 5-30 July 1993 on Ellesmere Island, Northwest Territories, traveled nomadically around an area >381 km2 but the alpha pair sometimes left the yearlings at a rendezvous site. All pack members hunted Arctic hares. The alpha pair sometimes fed the yearlings, the alpha male doing so more than the alpha female.

Canadian Field-Naturalist↗
USGS2001

Inability to predict geographic origin of Yellow-headed Blackbirds, Xanthocephalus xanthocephalus, during migration

Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) collected at different breeding locations in Alberta, Saskatchewan, Manitoba, and North Dakota exhibit clearly discernable morphometric differences with larger bodied birds found at more northern and western locations. We reduced eight skeletal measurements and body length from adult female and male Yellow-headed Blackbirds to their first two principal components. Principal component scores progressively increased at more northwestern locations. Principal component scores were also derived from measurements of birds collected in central North Dakota throughout summer and fall. We hypothesized an increase in principal component scores of Yellow-headed Blackbirds from summer through fall within central North Dakota as larger bodied migrants arrived and displaced local breeding birds. However, we were unable to detect an increase in principal component scores from mid-June though mid-September over two years of study. Discriminant models that were developed to distinguish birds breeding in Canada from those breeding in the USA were poor predictors of the migratory status of Yellow-headed Blackbirds. Thus, we were unable to exploit the morphometric differences inherent among Yellow-headed Blackbirds breeding at different geographic locations to quantify the timing or the magnitude of their migration through central North Dakota.

Canadian Field-Naturalist↗
USGS2009

Historical range, current distribution, and conservation status of the Swift Fox, Vulpes velox , in North America

The Swift Fox ( Vulpes velox ) was once common in the shortgrass and mixed-grass prairies of the Great Plains of North America. The species' abundance declined and its distribution retracted following European settlement of the plains. By the late 1800s, the species had been largely extirpated from the northern portion of its historical range, and its populations were acutely depleted elsewhere. Swift Fox populations have naturally recovered somewhat since the 1950s, but overall abundance and distribution remain below historical levels. In a 1995 assessment of the species' status under the US Endangered Species Act, the US Fish and Wildlife Service concluded that a designation of threatened or endangered was warranted, but the species was "precluded from listing by higher listing priorities." A major revelation of the 1995 assessment was the recognition that information useful for determining population status was limited. Fundamental information was missing, including an accurate estimate of the species' distribution before European settlement and an estimate of the species' current distribution and trends. The objectives of this paper are to fill those gaps in knowledge. Historical records were compiled and, in combination with knowledge of the habitat requirements of the species, the historical range of the Swift Fox is estimated to be approximately 1.5 million km 2 . Using data collected between 2001 and 2006, the species' current distribution is estimated to be about 44% of its historical range in the United States and 3% in Canada. Under current land use, approximately 39% of the species' historical range contains grassland habitats with very good potential for Swift Fox occupation and another 10% supports grasslands with characteristics that are less preferred (e.g., a sparse shrub component or taller stature) but still suitable. Additionally, land use on at least 25% of the historical range supports dryland farming, which can be suitable for Swift Fox occupation. In the United States, approximately 52% of highest quality habitats currently available are occupied by Swift Foxes.

Canadian Field-Naturalist↗
USGS1999

First record of coccidiosis in Wolves, Canis Lupus

Three 4-month-old Wolf (Canis lupus) pups in the Superior National Forest of Minnesota died during August and September 1997, apparently from coccidiosis. This appears to be the first record of coccidiosis in Wolves.

Minnesota↗
USGS1999

Six-egg clutches of the Mountain Plover, Charadrius montanus

Three six-egg clutches of the Mountain Plover (Charadrius montanus) represent the largest clutch size ever reported for this declining Great Plains shorebird. Clutch size in this species is normally three eggs, and six-egg clutches probably represent the laying of a second clutch in the nest by the same female.

Canadian Field-Naturalist↗
USGS2000

Coyote, Canis latrans, use of commercial sunflower, Helianthus spp., Seeds as a food source in western Kansas

Food habits of Coyotes (Canis latrans) were determined by analysis of scats collected in western Kansas in 1996. Mammals were the most frequently occurring food of Coyotes (100% of scats), followed by plants (39%), insects (30%) and birds (9%). Commercial sunflower (Helianthus spp.) seeds were found in 9 of 23 scats. When present, they composed a high volume of individual scats (X= 31%). Substantial use of commercial sunflower seeds as a food source by Coyotes has not been previously documented.

Canadian Field-Naturalist↗
USGS2000

Orphan caribou, Rangifer tarandus , calves: A re-evaluation of overwinter survival data

Low sample size and high variation within populations reduce power of statistical tests. These aspects of statistical power appear to have affected an analysis comparing overwinter survival rates of non-orphan and orphan Caribou ( Rangifer tarandus ) calves by an earlier study for the Porcupine Caribou Herd. A re-evaluation of the data revealed that conclusions about a lack of significant difference in the overwinter survival rates between orphan and non-orphan calves were premature.

Canadian Field-Naturalist↗
USGS2000

Breeding Atlantic Puffins, Fratercula arctica, and other birds species of Coburg Island, Nunavut

Coburg Island and neighbouring waters were recently designated a Canadian National Wildlife Area. The large seabird colony at Cambridge Point has been previously described, and is dominated by Thick-billed Murres (160 000 pairs). We found that a small offshore island, named Princess Charlotte Monument, also supported breeding populations of seven marine bird species; three of which did not breed at the main colony (i.e., Northern Fulmar, Common Eider, and Atlantic Puffin). This is the most northern confirmed breeding site for Atlantic Puffins in Canada. Puffins at both Coburg Island and northern Greenland nest in rock crevices, apparently because permafrost in soil prevents burrow nesting. We suggest that puffin populations in the high arctic may be limited by habitat, rather than prey availability.

Canadian Field-Naturalist↗