The Status and Distribution of Trumpeter Swans (&lt;i&gt;Cygnus buccinator&lt;/i&gt;) in the Yukon

McKelvey, Richard W.; Dennington, Malcolm C.; Mossop, David

doi:10.14430/arctic2245

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…Beaver activity has an important influence on the development of ponds used by trumpeter swans Cygnus spp. (McKelvey, Dennington & Mossop, 1983). Swans and Canada geese Branta canadensis often build nests on the tops of lodges (Brenner, 1960; Hilfiker, 1991).…”

Section: Ecological Impact On Other Species Of Animalsmentioning

confidence: 99%

Ecological impact of beaversCastor fiberandCastor canadensisand their ability to modify ecosystems

et al. 2005

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1.The genus Castor comprises two species: the Eurasian beaver Castor fibre , and the North American beaver Castor canadensis . Both species suffered from overexploitation, but have seen a revival since the 1920s due to increased protection and reintroduction programmes. Increases in the populations and distributions of species that are able to modify ecosystems have generated much scientific interest. Here we review the available literature concerning the possible ecological impact of beaver species in the Old and New World. 2. Beavers, being ecosystem engineers, are among the few species besides humans that can significantly change the geomorphology, and consequently the hydrological characteristics and biotic properties of the landscape. In so doing, beavers increase heterogeneity, and habitat and species diversity at the landscape scale. Beaver foraging also has a considerable impact on the course of ecological succession, species composition and structure of plant communities, making them a good example of ecologically dominant species (e.g. keystone species). 3. Nevertheless, the strength of beavers' impact varies from site to site, depending on the geographical location, relief and the impounded habitat type. Consequently, they may not be significant controlling agents of the ecosystem in all parts of their distribution, but have strong interactions only under certain circumstances. We suggest that beavers can create important management opportunities in the Holarctic, and this review will help land managers determine the likely outcome of beaver activity.

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Section: Ecological Impact On Other Species Of Animalsmentioning

confidence: 99%

Ecological impact of beaversCastor fiberandCastor canadensisand their ability to modify ecosystems

et al. 2005

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“…Comox is an attractive wintering area for swans, probably because of extensive food resources and its position relative to the swans' migration route. Resightings of birds neck-collared in Powell River, British Columbia, indicate an interior migration route with egress to the coast via the mainland inlets Knight, Bute and Toba (McKelvey and Burton 1983). Swans following the interior route will arrive at Comox, which may be the first major area of wintering habitat they encounter.…”

Section: Discussionmentioning

confidence: 99%

Habitat use, behaviour, and management of Trumpeter Swans, Cygnus buccinator, wintering at Comax, British Columbia

McKelvey,

Verbeek

1988

The Canadian Field-Naturalist

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Of eight categories of behaviour exhibited by Trumpeter Swans (Cygnus buccinator) wintering at Comox, feeding was the dominant activity in daylight periods (37.7% of the time), but sleeping predominated during the night (41.5%) and over the total 24-hour period (36.0%). Feeding on dairy pastures occurred only during daylight and accounted for 74.6% of the time spent there. All behaviours were reducible to two basic types -foraging and resting. On average 57.6% of a given daylight period and 47.2% of a night period were spent foraging on the estuary, while 87.1% of daylight time on dairy pastures was spent foraging. Feeding on the estuary was regulated by tidal conditions. At night there was a slight negative correlation between numbers feeding and temperature. Other environmental factors were not found to be important influences. During grazing on dairy pastures, foraging was more or less constant, with no daily peaks of intensity. Dogs were the most effective method of discouraging swans from grazing on pastures. The provision of alternate food sources is not recommended.

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“…The majority of swan mortalities in British Columbia were reported during November to May from the Lower Fraser Valley and south-eastern Vancouver Island; these areas support large wintering populations of Trumpeter Swans (McKelvey et al 1991;Boyd 1994). The large number of reported deaths may also be a consequence of these areas supporting dense human populations which may observe and report swan mortalities.…”

Section: Swan Mortalitymentioning

confidence: 99%

Lead poisoning of Trumpeter Swans, Cygnus buccinator, in British Columbia, 1976-1994

Wilson,

Elliott,

Langelier

et al. 1998

The Canadian Field-Naturalist

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Lead poisoning from ingestion of lead shot is a cause of death of Trumpeter Swans (Cygnus buccinator) wintering on the southern coast of British Columbia. Between 1976 and 1994, 186 Trumpeter Swans were found either dead or sick in British Columbia; 87 (47%) were diagnosed with acute lead toxicosis. The largest die-off of 32 Trumpeter Swans occurred at Judson Lake in 1992. Tissues from 102 swans were analyzed for lead; 65 (64%) were classified as lead-poisoned. Lead residues detected in kidney, liver, bone, and blood samples of lead-poisoned swans averaged 30.6 mg/g, 23.7 mg/g, 18.3 mg/g and 4.4 mg/g wet weight, respectively. Ingested lead shot were detected in gizzards of 46 of the 62 lead-poisoned swans examined; number of pellets per gizzard were counted in 34 swans with an average of 16.8 pellets per bird (range:1-80, SD 17.3). Steel shot were detected in the gizzards of 18 of the 62 lead-poisoned swans examined; number of pellets per gizzard were counted in nine swans with an average of 3.3 pellets per bird (range:1-11, SD 3.2). Although the use of lead shot for waterfowl hunting has been banned in the main wintering areas of Trumpeter Swans since 1990, these birds continue to die from lead poisoning. Despite the high rate of unnatural mortality among Trumpeter Swans reported to our agency, their populations in the region currently are increasing. Lead poisoning as a threat to Trumpeter Swan populations in British Columbia is assessed.

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The Status and Distribution of Trumpeter Swans (<i>Cygnus buccinator</i>) in the Yukon

Cited by 5 publications

References 2 publications

Ecological impact of beaversCastor fiberandCastor canadensisand their ability to modify ecosystems

Ecological impact of beaversCastor fiberandCastor canadensisand their ability to modify ecosystems

Habitat use, behaviour, and management of Trumpeter Swans, Cygnus buccinator, wintering at Comax, British Columbia

Lead poisoning of Trumpeter Swans, Cygnus buccinator, in British Columbia, 1976-1994

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