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Item Open Access A comparison of the Characteristics and Fate of Barrow's Goldeneye and Bufflehead Nests in Nest Boxes and Natural Cavities(University of California Press, 2002) Evans, M.R.; Lank, D.B.; Boyd, W.S.; Cooke, F.Abstract. Barrow's Goldeneye (Bucephala islandica) and Bufflehead (B. albeola) are cavity-nesting waterfowl that have received considerable attention in studies using nest boxes, but little is known about their nesting ecology in natural cavities. We found larger clutch size, lower nesting success, and different major predators for Barrow's Goldeneyes nesting in boxes versus those nesting in natural cavities, but few differences for Bufflehead. These differencesa re attributedt o the location and physical differencesb etween Barrow's Goldeneyen est boxes and naturalc avities that affect theirc onspicuousnesst o predatorsa nd conspecific nest-parasitizingfe males. Goldeneyeb oxes were concentratedin highly visible locations such as trees at water or forest edge. Natural cavity nests, on the other hand, were often abandoned Pileated Woodpecker (Dryocopus pileatus) cavities, which were more dispersed throughout the forest interior and concealed under dense canopy cover. Bufflehead natural cavity nests were typically closer to edges, which may account for their similarity with boxes. We conclude that in some respects, studies of Barrow's Goldeneye that use nest boxes may not be representativeo f birds nesting in naturalc avities, whereast hose of Bufflehead are more likely to be so.Item Open Access A comparison of the growth responses of three sedges to foraging by lesser snow geese.(1987) Kotanen, Peter M.SUMMARY:Item Open Access A cook Shack at Camp Finney being used for field research, 1967.(1967-04) Abraham, KenItem Open Access Item Open Access A genetic analysis of Lesser Snow Goose families.(University of California Press, 1972) Cooke, F.; Mirsky, P.J.Item Open Access A Nodwell Vehicle at Camp Finney Being used for Lesser snow Geese Field Research, 1967.(1967-04) Abraham, KenItem Open Access A plane landing in Churchill, Manitoba, 1967.(1967) Abraham, KenItem Open Access A Remembrance and Celebration of the Life of Robert Lenthall Jefferies(University of Toronto, 09/11/2009)Item Open Access A windswept areas for the arriving geese to search for food in camp Finney, 1967.(06/05/1967) Abraham, KenItem Open Access Adult Blue Goose defending nest(08/04/2013) Cooke, FredItem Open Access Age-specific costs of first-time breeding(University of California Press, 1995) Viallefont, A.; Cooke, F.; Lebreton, D.We investigated the cost of first-time breeding in a population of Lesser Snow Geese (Anser caerulescens caerulescens) nesting at La Perouse Bay, Manitoba, Canada. We estimated local survival and capture probabilities of female geese by capture-recapture analysis. We first found that birds were less likely to be recaptured one year after their first successful breeding than on later occasions. Since only successfully nesting birds are captured, this suggests that first-time breeding affects the ability of nesting the next year. We then show that this effect of first breeding is much more severe for birds nesting at age 2 (the youngest age at which Lesser Snow Geese can breed) than for birds starting to breed at an older age. Finally, we compare the mean expected lifetime reproductive success for birds breeding for the first time as two-year-olds or as three-year-olds, conditionally on their survival until age 4. On average, birds first nesting as two-year-olds produce similar numbers of offspring in a lifetime as birds starting at age 3.Item Open Access Allochthonous inputs: integrating population changes and food-web dynamics(Elsevier, 2004) Jefferies, Robert L.Most ecosystems are recipients of allochthonous materials that enhance in situ productivity. Recent theoretical and empirical studies suggest that low to moderate inputs can stabilize food webs. However, depending on the trophic levels that use the resource, food webs can become unstable as inputs increase. Where large amounts of agricultural resources are transferred to natural habitats, trophic dynamics change: trophic cascades can occur and rare or uncommon species can become invasive. Rates of change in species abundances can also be amplified by the effects of changes in legislation and management practices on subsidized consumers.Item Open Access Annual Variation in Cohort-Specific Adult Tarsus Length(06/03/2013) Cooke, FredItem Open Access Body size and fecundity in lesser snow geese: response to Alisauskas and Ankney.(University of California Press, 1990) Cooke, F.; Davies, J. C.; Rockwell, R. F.Item Open Access Body size variation and fitness components in lesser snow geese Chen caerulescens caerulescens.(University of California Press, 1988) Davies, J.C.; Rockwell, R.F.; Cooke, F.We examined the potential action of selection on body size in a population of Lesser Snow Geese (Chen caerulescens caerulescens) breeding in the Canadian subarctic. We evaluated the genetic basis of phenotypic variation in body size and examined the association of body size and components of fitness related to fecundity and viability. There was a heritable component to body size in this population derived in part from the action of additive genes. There was no relation between adult body size and the number of eggs laid, the number of eggs surviving predation, the number of goslings that left the nest, or the number of goslings fledged. Small birds entered the breeding population at a younger age. They did so with no reduction in viability and may actually live longer than large birds. The heritable variation in body size combined with the directional selection gradient should lead to a gradual reduction in adult body size in this population. We found no evidence for such a change over 5 generations. We discuss this in terms of additional fitness components, the retarding effects of age structure on the response to selection, and the interaction of selection and gene flow. Received 6 October 1987, accepted 8 May 1988.Item Open Access Body weight and feather growth of male Barrow's Goldeneye during wing molt.(University of California Press, 2000-02) Van der Wetering, D.; Cooke, F.We studied the timing, duration, and rate of wing molt of male Barrow's Goldeneye (Bucephala islandica). The mean daily change in primary feather length was 2.6%, which is consistent with rates reported for other waterfowl species. The mean length of the flightless period was 31 days (range: 27-34 days), excluding the pre-shedding interval. Wing molt extended from early July to mid-September. Peak wing molt occurred between 20 July and 23 August. The mean body weight of adult males decreased significantly during wing molt. Heavier birds had greater remigial growth rates and experienced more substantial declines in body weight than lighter birds, suggesting that body reserves may be used to increase the rate of remigial growth.Item Open Access Breeding ecology of radio-marked Marbled Murrelets, Brachyramphus marmoratus, in Desolation Sound, British Columbia(Ottawa : National Library of Canada = Bibliothèque nationale du Canada, 2002) Bradley, Russell W.Understanding the population biology of a species requires thorough study of its breeding behaviour and success. The Marbled Murrelet is a small alcid seabird which cryptically nests at inland sites in old-growth trees. Concern for murrelet populations, primarily from breeding habitat loss, has led to listing of the species as threatened or endangered over most of its range. However, because of its elusive breeding, reproductive ecology of Marbled Murrelets is still poorly understood. I investigated the breeding ecology of radio marked Marbled Murrelets in Desolation Sound, British Columbia. Movement patterns of radioed birds showed that breeding state and success can be accurately inferred with radio telemetry. Male breeding birds visited their nests, and likely provisioned young, more than females during chick rearing. The male bias was primarily due to a reduction in female visitation during late chick rearing. These findings offer a behavioral explanation for the annual male bias of birds flying inland during the chick rearing period at Theodosia Inlet in Desolation Sound from 1994-1999. Early breeding birds commuted further from foraging areas to nests, and nested at sites of steeper slopes than later breeding birds. Earlier breeding birds were more successful, while higher nest site elevation, steeper nest site slope, and longer commuting distance were all associated with greater success. Data from radio marked birds showed no evidence to suggest that nesting near forest edges, particularly natural edges, reduces reproductive success in Marbled Murrelets. Advantages of steeper nest site slopes and close proximity to edges, like nest site access, may outweigh the potential costs of nest predation in our study location, which is free of human habitation in murrelet breeding areas.Item Open Access Bruce Rattray and Sue Cargill in the North Elymus Area, 1978.(1978-05-21) Abraham, KenItem Open Access Item Open Access Changes in Survival Rates of Lesser Snow Geese with Age and Breeding Status(University of California Press, 1992) Francis, C.M.; Richards, M.H.; Cooke, F.; Rockwell, R.F.Survival rates of Lesser Snow Geese (Chen caerulescens caerulescens) were examined based on recoveries and recaptures of about 350,000 geese banded at breeding colonies in northern Canada, at migration stopover points in the Dakotas and Missouri, and on the wintering grounds in Louisiana and Texas. First-year survival rates for goslings banded on the breeding grounds varied from 10 to 70% of adult survival rates. Much of the juvenile mortality occurred on the breeding grounds or early on the first migration. Young geese that reached migration stopovers or the wintering grounds were more vulnerable to hunters than adults, but had only slightly lower survival rates than adults. Greater vulnerability and lower survival continued through the second year of life, even though yearlings do not breed. In contrast, older birds that did not breed, or failed early in a nesting attempt, were much less vulnerable to hunters in the following hunting season than successful breeding adults, but did not appear to have higher survival as a result. Geese captured for the first time as breeding adults had slightly lower survival rates than geese that had been recaptured at the colony at least once, suggesting experienced breeders have higher survival. Although there was some evidence that older birds were slightly more vulnerable to hunters, there were no signs of any changes in survival rate with age in older geese, indicating that senescence, if it affects survival, does not do so for at least the first 10 to 15 years of age. With current hunting levels, less than 5% of Lesser Snow Geese are likely to live beyond this age. Our study demonstrates a variety of statistical methods for testing hypotheses about age-specific survival using both recovery and recapture data, even when the data do not permit estimation of the exact survival rates.