The Canadian Field-Naturalist

Fox populations introduced before 1930 for fur farming have devastated breeding avifauna on numerous islands in S Alaska. To restore populations of endangered Aleutian Canada goose Branta canadensis leucopareia, seabirds, and other avifauna on Alaskan islands, foxes must first be removed. Sterile red foxes were introduced to two Aleutian Islands in 1983 and 1984 to determine their ability to eradicate Arctic foxes. By the summer of 1992 some red foxes still remained on one island, but Arctic foxes apparently were absent from both. -from Author

The 18 den and 6 rendezvous sites had an average of 4.5 holes per site. No significant differences existed between the average number of holes between den and rendezvous sites. Mean dimensions of tunnel entrances and chambers are reported. No correlation existed between numbers of wolves which had used a site and numbers of holes. Den and rendezvous sites were usually located on knolls or hillsides with sandy, frost-free soil and mixed, semi-open stands of spruce Picea spp., quaking aspen Populus tremuloides, and willow Salix spp. Wolves generally selected sites with south and/or east exposures. Mean distance to water was 257 m. Average distance between contiguous, concurrent den sites was 45.3 km.-from Authors

Radiocollared black bears (Ursus americanus) were studied near Fort McMurray, Alberta, during June-October 1976. Four females without cubs occupied areas averaging 7.5 km2 During summer and fall, stands of spruce (Picea spp.) and open muskegs were used less often than predicted from random sampling, whereas mixed aspen (Populus tremuloides) and Jack Pine (Pinus banksiana) were used more often. Six radiocollared bears denned between 19 September and 29 October. Five dens were excavated on level ground; four were in stands (<l5 cm DBH) of mixed aspen and birch (Betula papyrifera) and had likely been dug in previous years.

In order to describe the vascular plant community 100 days after a severe fire in alvar woodland near Ottawa, Ontario, we set out fifty one m square quadrats at 5 m intervals along transects at each of five sites and recorded presence and cover of vascular plant species in each quadrat. The woodlands that burned were dominated by Thuja occidentalis, Populus tremuloides, Abies balsamea, Picea glauca, and Pinus strobus in approximate order of importance. The post-fire flora was diverse and mostly native. Although substantial variation occurred in presence, frequency and cover of species between the sites, there was remarkable similarity in a distinctive group of dominants including Populus tremuloides, Geranium bicknellii, and Corydalis aurea. Rare species present in the burned woodland included Astragalus neglectus, Calystegia spithamaea, Carex richardsonii, Corydalis aurea, Muhlenbergia glomerata, Panicum flexile, Panicum philadelphicum, Petasites frigidus, Scutellaria parvula, and Viola nephrophylla. Of these, Corydalis aurea and Calystegia spithamaea were frequent. The development of vascular flora following the fire was a consequence of growth from roots, rhizomes, and root crowns that survived the fire, and seeds buried in the soil. Although abundant in the burned woodland, Corydalis aurea and Dracocephalum parviflorum had not been previously recorded at the site, suggesting that these species are adapted to early post-fire succession, surviving periods of up to 130 years between fires as seeds in a very large and widespread subterranean seed bank. Not only is post-fire succession well underway within a hundred days of a fire, but even in its earliest stages, it appears to serve as a specific niche for a distinctive group of species including some that are rare and restricted. A diverse native flora is involved indicating the importance of management involving removal of woody biomass.

It is well recognized that differences in environmental selection pressures among populations can generate phenotypic divergence in a suite of morphological characteristics and associated life history traits. Previous analysis of mitochondrial DNA and body size have suggested that Black Bears (Ursus americanus) inhabiting the island of Newfoundland represent a different subspecies or ecotype from mainland populations. Assuming that body size covaries positively with skull size, we predicted that skull size would be greater for bears on the island than the mainland, and the distribution of size-related shape components in multivariate space should show a distinct separation between Newfoundland and mainland populations. Measurements of 1080 specimens from Newfoundland, Alberta, New York, and Quebec did not provide unequivocal support for our prediction that skull size in Newfoundland bears would be larger than bears from the mainland populations. After removing ontogenetic effects of skull size, between-population variation in skull shape was greater in females than males, and the analysis significantly separated Newfoundland bears from mainland populations. Explanations for this pattern are numerous, but currently remain hypothetical. Limited covariation between skull size and body size suggests that genetic traits regulating the size of Black Bear skulls are more heritable (i.e., less influenced by environmental selection pressures) than characteristics affecting body size. We hypothesize that if gape size does not limit prey size in solitary terrestrial carnivores, large degrees of among-population variation in body size should be coupled with little covariation in skull size. In general, sexual dimorphism in skull size and shape was marginal for the phenotypic characters measured in our study. We believe that sexual dimorphism in skull size in Black Bears is primarily driven by intrasexual selection in males for increased gape size display, while similarity in skull shape between sexes is associated with the constraints of a temporally-selective, but similar diet.

Two adult free-ranging Eurasian Beavers (Castor fiber) were observed depositing anal gland secretion at the border of thei territory byeverting the "cloaca", protruding the anal gland openings and rubbing them against the surface as the anin1a walked over the scent mound. We suggest that anal gland secretion applied to scent marks on land has some as ye unknown function in territory defense of the Eurasian Beaver.

Aspen (Populus tremuloides) communities were measured in and near Yoho and Kootenay National Parks to determine condition and trend. Most aspen stands were heavily invaded by conifers as they had not burned in 60 years or more due to modern fire suppression and the elimination of aboriginal burning. Aspen is also declining due to repeated ungulate browsing, primarily by Elk (Cervus elaphus). Even where disturbed by logging and burning outside the parks, many aspen stands failed to produce new stems greater than 2 m tall because all the suckers were repeatedly browsed. Only where ungulate numbers were low was aspen able to successfully regenerate. Aspen, though, is not 'seral', as that term is commonly used because the species seldom grows from seed due to its demanding seed bed requirements. This, coupled with high biodiversity, makes aspen an excellent indicator of ecological integrity as mandated by Parks Canada statute.

Based on the life-form and their utility to Beavers (Castor canadensis), we classified the riparian plants around Beaver impoundments into five categories: Alder (Alnus spp.) - dam construction; Trembling Aspen (Populus tremuloides) - primary food; White Birch (Betula papyrifera) and Willows (Salix spp.) - secondary foods; shrubs - occasionally used for food and dam construction; and conifers - occasionally used for dam construction. To study the influence of Beaver herbivory on shoreline woody plants, we randomly chose eight recently active (< 5 years since establishment), seven recently abandoned (< 12 years since abandonment), and eight old abandoned (> 12 years since abandonment) dam sites. We found that Beavers concentrated the majority of their herbivory to within 20 m of the impoundment edge. Three explanations are proposed: (1) thermoregulatory restrictions; (2) directionally leaning trees within riparian habitats; and (3) reduction of predation risk. After 12+ years of abandonment, we found the Beaver's preferred food tree, the Trembling Aspen, had not re-established along streams adjacent to abandoned dam sites. In contrast, less desirable food trees and conifers showed increased recovery. If this selective herbivory continues unchecked, the riparian habitat along the Swanson River will become dominated by conifers and thus unsuitable for sustaining Beavers. We believe that fire is needed to rejuvenate the failing Trembling Aspen stocks.

We trapped three adult Eurasian Pine Martens (Martes martes) at an earlier trapped-out Eurasian Beaver (Castor fiber) lodge in southem Norway. At another site, Pine Marten feces containing remains of beaver claws and hair were found outside a beaver lodge. Pine Martens apparently feed on beavers and use their abandoned lodges as resting sites.

The death of a Eurasian Beaver Castor fiber caused by a collapsing burrow in southeast Norway is reported. Two days of heavy rainfall had presumably caused the burrow to collapse, suffocating the animal.

The gizzards of three female Whimbrels collected on breeding grounds at Churchill, Manitoba, contained the bones of Wood Frogs. This is the first record of Whimbrels feeding on vertebrates of any kind in America.

Seven methods used to color mark ducklings for the purpose of individual identification were evaluated for retention on groups of domestic ducklings Marker loss varied considerably among methods and only nasal discs gave satisfactory retention beyond five days. This method of marking ducklings is tentatively recommended for studies concentrating on duckling movement and behavior. Furthermore, it is recommended that before any technique is used, the rate of marker loss be considered in light of the potential to influence results.

Thesis (M.S.)--Humboldt State University. Bibliography: ℓ. 56-59.

Environmental contaminants (e.g., DDT: dichloro diphenyl trichloroethane) can bioaccumulate in ecosystems, causing reproductive failure and death among species at higher trophic levels. We examined levels of DDT among Soricidae from forested sites in northern Maine in control areas and areas that were sprayed with DDT to control Spruce Budworm (Choristonneura fumiferana). We also examined persistence of DDT in Soricidae six times over 28 years, 1966-1994. Mean total DDT levels were significantly higher (P<0.05) in Soricidae from sprayed areas than control areas in most years, yet levels have declined significantly (P<0.05) over time. Mean DDT levels in insectivorous small mammals had not reached pretreatment levels, even 30 years after spraying had ceased. Prevalence of DDT metabolites confirmed that contamination in this location is from previous and not current sources.

Both Mule Deer (Odocoileus hemionus) and White-tailed Deer (Odocoileus virginianus) have colonized the southern half of the Yukon in recent decades. Mule Deer have attained a continuous distribution in suitable habitats, White-tailed Deer have remained rare. Deer habitats are largely open, south-facing grassy slopes bordered by aspen, sites of recent forest fires, and cultivated hay fields. Many sightings have been reported by the general public. These have been supplemented by interviews of native elders and other long-time residents and a literature search. Mule Deer first appeared in the Yukon in the late 1930s to early 1940s and by the 1980s had reached the latitude of Dawson (64° N) and crossed into Alaska in the Ladue River drainage. A northern record for Mule Deer was established with a sighting near Chapman Lake along the Dempster Highway (64° 50′ N, 138° 25″ W). White-tailed Deer are more recent, first observed near the British Columbia border (60° 10′ N) at Tagish Lake in 1975 and reaching Moose Creek along the Klondike Highway (63° 30′ N) in 1998.

Saxifraga spicata (Micranthes spicata (D. Don) Small), a large perennial showy saxifrage endemic to the unglaciated regions of Alaska andYukon, was rediscovered after not having been seen in Canada for 110 years.

Igl, L. D., D. H. Johnson, and H. A. Kantrud. 1999. Uncommon breeding birds in North Dakota: population estimates and frequencies of occurrence. The Canadian Field-Naturalist 113(4): 646-651. The last digit was inadvertently omitted from the confidence intervals for two species in Table 1. The population estimate (1000s of pairs) for the Ruddy Duck in 1993 should be 50 (0-93) rather than 50 (0-9), and the population estimate (1000s of pairs) for the Dickcissel in 1992 should be 74 (7-140) rather than 74 (7-14). The authors thank C. Stuart Houston for bringing these errors to their attention.

The abbreviation for concentrations in micrograms per gram of dry weight should be corrected in two places. On page 120 "mg/g" left column line 18, and right column line 21, should be "μg/g".

FIGURE 1. Map of Haida Gwaii showing locations mentioned in the text and collection sites of introduced marine plant and invertebrate species, based on data from Sloan and Bartier (2000) and Sloan et al. (2001).

Article title was incorrectly listed.

Previous reports of two flora taxa are added.

Page 46: Addition to Literature Cited:Gosse, J., J. W. Cox, and S. W. Avery. 2005. Home-range characteristics and habitat use by American martins in eastern Newfoundland. Journal of Mammalogy 86: 1156-1163.