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Erika K. Lok Daniel Esler John Y. Takekawa Susan W. de la Cruz W. Sean Boyd David R. Nysewander Joseph R. Evenson David H. Ward 《The Journal of wildlife management》2011,75(1):92-100
Habitat conditions and nutrient reserve levels during spring migration have been suggested as important factors affecting population declines in waterfowl, emphasizing the need to identify key sites used during spring and understand habitat features and resource availability at stopover sites. We used satellite telemetry to identify stopover sites used by surf scoters migrating through southeast Alaska during spring. We then contrasted habitat features of these sites to those of random sites to determine habitat attributes corresponding to use by migrating scoters. We identified 14 stopover sites based on use by satellite tagged surf scoters from several wintering sites. We identified Lynn Canal as a particularly important stopover site for surf scoters originating throughout the Pacific winter range; approximately half of tagged coastally migrating surf scoters used this site, many for extended periods. Stopover sites were farther from the mainland coast and closer to herring spawn sites than random sites, whereas physical shoreline habitat attributes were generally poor predictors of site use. The geography and resource availability within southeast Alaska provides unique and potentially critical stopover habitat for spring migrating surf scoters. Our work identifies specific sites and habitat resources that deserve conservation and management consideration. Aggregations of birds are vulnerable to human activity impacts such as contaminant spills and resource management decisions. This information is of value to agencies and organizations responsible for emergency response planning, herring fisheries management, and bird and ecosystem conservation. © 2010 The Wildlife Society 相似文献
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Anthony Roberts Emily Silverman Suzanne Gifford 《The Journal of wildlife management》2018,82(7):1536-1544
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Quantifying survival and understanding underlying sources of variation are important for developing population models and informing management decisions. We estimated apparent survival (i.e., true survival less permanent emigration) for adult female white-winged scoters (Melanitta fusca) and lesser scaup (Aythya affinis) breeding at a northern boreal forest site in western Canada, 2002–2008. We also evaluated variation in survival relative to indices of breeding status, individual quality, spring weather conditions, local small-mammal abundance, and overwinter climate. Breeding female scoters had higher apparent survival than did nonbreeding females, suggesting that breeders had higher survival or fidelity to the study area, or that more nonbreeders were transient birds that may have bred elsewhere in subsequent years. Apparent survival rate for breeding female scoters was unrelated to other individual and environmental covariates. Nest-trapped female scaup had higher apparent survival rates than did prenesting females captured in decoy traps, implying that more pre-nesters dispersed permanently or died after marking. Nesting female scaup with higher body condition or those in years when small mammals were more abundant had higher apparent survival; associations between survival and other environmental covariates were less certain. Overall, apparent survival rate of breeding adult female scoters was lower than reported for scoters from other North American locations or for other sea duck species, whereas estimates for nesting female scaup were comparable with those from other boreal and prairie-parkland locations. Our results indicate that for scaup in this region, factors influencing female body condition, such as maintaining high-quality habitat, areas with abundant food or low disturbance, could improve annual survival. © The Wildlife Society, 2019 相似文献
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High rates of site fidelity have been assumed to infer static distributions of molting geese in some cases. To test this assumption, we examined movements of individually marked birds to understand the underlying mechanisms of range expansion of molting Black Brant (Branta bernicla nigricans) on the Arctic Coastal Plain (ACP) of Alaska. The Teshekpuk Lake Special Area (TLSA) on the ACP was created to protect the primary molting area of Brant. When established in 1977, the TLSA was thought to include most, if not all, wetlands used by molting Brant on the ACP. From 2010 to 2013, we surveyed areas outside the TLSA and counted an average of 9800 Brant per year, representing 29–37% of all molting Brant counted on the ACP. We captured and banded molting Brant in 2011 and 2012 both within the TLSA and outside the TLSA at the Piasuk River Delta and Cape Simpson to assess movements of birds among areas across years. Estimates of movement rates out of the TLSA exceeded those into the TLSA, demonstrating overall directional dispersal. We found differences in sex and age ratios and proportions of adult females with brood patches, but no differences in mass dynamics for birds captured within and outside the TLSA. Overall fidelity rates to specific lakes (0.81, range = 0.49–0.92) were unchanged from comparable estimates obtained in the early 1990s. We conclude that Brant are dispersing from the TLSA into new molting areas while simultaneously redistributing within the TLSA, likely as a consequence of changes in relative habitat quality. Shifts in distribution resulted from colonization of new areas by young birds as well as low levels of directional dispersal of birds that previously molted in the TLSA. Based on combined counts, the overall number of molting Brant across the ACP has increased substantially. 相似文献
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Danica Hogan Jonathan E. Thompson Daniel Esler 《The Journal of wildlife management》2013,77(4):701-706
Postbreeding survival of waterfowl is rarely quantified, despite potential for constraints during this stage of the annual cycle that may subsequently affect population dynamics. We estimated survival of radio-marked adult male Barrow's goldeneyes (Bucephala islandica) during remigial molt and fall staging at Cardinal and Leddy Lakes in the Boreal Transition Zone of northwestern Alberta, Canada. Daily survival rate (DSR) was high during remigial molt (DSR = 0.9987, 95% CI: 0.9967–1.0000), corresponding to a 39-day period survival rate (PSR) of 0.95 (95% CI: 0.88–1.00). During fall staging, DSR was markedly lower (DSR = 0.9938, 95% CI: 0.9898–0.9978), corresponding to a PSR of 0.68 (95% CI: 0.53–0.87) over the 62-day period between the end of remigial molt and fall migration. Half of fall staging mortalities observed on Cardinal Lake were directly attributed to hunting. We conclude that remigial molt is a period with high survival in the annual cycle of Barrow's goldeneyes at our study sites. However, in light of low fall staging survival, Barrow's goldeneye harvest management strategies should be carefully evaluated with intent to reduce risk of localized high mortality at significant staging sites in western Canada. © 2013 The Wildlife Society. 相似文献
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Barbara A. Lagerquist Bruce R. Mate Joel G. Ortega‐Ortiz Martha Winsor Jorge Urbán‐Ramirez 《Marine Mammal Science》2008,24(4):815-830
Humpback whales wintering in the Revillagigedo Archipelago, Mexico, have been considered a different subpopulation from those found off mainland Mexico and Baja California. The primary feeding grounds for Revillagigedo humpbacks remain unknown. In February 2003, we deployed 11 Argos satellite‐monitored radio tags to track movements and surfacings of humpback whales (five adults without calves, five mothers with calves, one calf) off Socorro Island in the Revillagigedo Archipelago. Tracking ranged from 222 to 10,481 km over 4.9–149.1 d. Eight whales left Socorro Island: five visited other Mexican wintering destinations, seven moved north of these areas. Migration routes were primarily offshore (average 444 km). Two whales were tracked to feeding grounds: one to British Columbia (46 d migration), and one to Alaska (49 d migration). Mean travel speeds were 1.2 km/h in wintering areas, 4.0 km/h during migration, and 2.2 km/h in feeding areas. Overall surfacing rates ranged from 21 to 88 surfacings/h. Surfacing rates differed between the calf and all other whales, and between feeding areas and migratory/wintering areas for the calf and an adult without a calf. The calf also showed diel variation in surfacing rates. The offshore habits of tagged whales may explain scarce resightings of Revillagigedo humpbacks outside the Revillagigedo Archipelago. 相似文献
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Paul A. Breen Wolfgang Carolsfeld K.Lynne Yamanaka 《Journal of experimental marine biology and ecology》1985,92(1):45-61
This study examined social behaviour of juvenile red sea urchins, Strongylocentrotus franciscanus (Agassiz). At four coastal locations in British Columbia, Canada, distributions of juvenile sea urchins were examined in relation to adults. One-third of all juveniles were found underneath an adult “spine canopy”, another third outside the spine canopy but close to an adult, and the remainder were found apart from adults. Juveniles associated with adults were contagiously distributed with each other. In the laboratory, juveniles chose adults over other target locations. They selected adults in particular locations over others, and in one case showed selection among adults; but they did not select between fed and non-fed adults, nor between adults that had been “protective” and “non-protective” of juveniles in the field. In time-lapse film studies, starved juveniles showed little change in social behaviour when food was introduced, but showed a dramatic change in behaviour when predators were active. We suggest that juvenile red sea urchins are found under the spine canopies of adults as a result of juvenile behaviour; and that this interaction functions to protect juveniles from predation. The strong gregarious nature of juveniles among themselves may have evolved in a different selective situation as a defence against predation and to ensure reproductive success. 相似文献
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The cultivation of the red alga Porphyra in North America to produce the edible product nori is now in its tenth year of development. Cultivation technology has been transferred and modified from Japan and Korea. Early efforts by the Washington State Department of Natural Resources indicated that cultivation is biologically feasible and could be economically viable. Commercial production has begun in Washington, U.S.A. and in British Columbia, Canada. Early products are of high quality. Constraints to more rapid development are institutional — obtaining necessary permits for use of water areas and financing is difficult.This paper is dedicated to the memory of Bud Brinkhuis — friend and fellow phycologist who will be missed by all of us growing seawwees. 相似文献
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Soraia Barbosa Kimberly R. Andrews Richard B. Harris Digpal S. Gour Jennifer R. Adams E. Frances Cassirer Hollie M. Miyasaki Helen M. Schwantje Lisette P. Waits 《The Journal of wildlife management》2021,85(6):1214-1231
Bighorn sheep (Ovis canadensis) populations in the western United States have undergone widespread declines and extirpations since the late nineteenth century as a consequence of introduced diseases, competition with livestock, and unregulated hunting. Washington, Idaho, USA, and British Columbia, Canada were historically thought to be occupied by 2 bighorn lineages or subspecies: Rocky Mountain (O. c. canadensis) and California (O. c. californiana). The putative California lineage was completely extirpated in the United States, and reintroductions to reestablish populations were sourced directly or indirectly from a single region in southern British Columbia. Restoration efforts have attempted to maintain the diversity and divergence of these 2 lineages, sometimes referred to as subspecies although taxonomic classifications have changed over time. In this study we describe genetic variation in a subset of native and reintroduced herds of California and Rocky Mountain bighorn sheep. We examined genetic diversity and divergence between bighorn sheep herds using 15 microsatellite loci, including 4 loci linked to genes involved in immune function. We analyzed 504 samples from reintroduced herds in Washington (n = 10 California herds, n = 4 Rocky Mountain herds) and Idaho (n = 5 California), and source herds in Oregon (n = 1 Rocky Mountain) and British Columbia (n = 5 California, 1 Rocky Mountain). Genetic structure reflected known reintroduction history, and geographic proximity also was associated with decreased genetic divergence. Herds in Washington and Idaho sourced from California bighorn sheep were less genetically diverse than those sourced from Rocky Mountain herds. Also, levels of relatedness within and across California herds were higher than in Rocky Mountain herds and similar to what would be expected for full and half siblings. Lower diversity and higher relatedness among California herds is a concern for long-term fitness and likely related to past population bottlenecks, fewer source populations, and management history, such as entirely sourcing California herds from British Columbia. Genetic divergence of neutral loci between California and Rocky Mountain herds was greater than that of adaptive loci, potentially indicating that balancing selection has maintained similar genetic diversity across lineages in loci associated with immune and other adaptive functions. Thus, we recommend future reintroductions and augmentations should continue to use source populations from the appropriate California or Rocky Mountain lineage to avoid potential outbreeding depression and maintain possible adaptive differences. This could be accomplished by obtaining sheep from ≥1 source within the genetic lineage, while avoiding sourcing from admixed herds. Future work encompassing a broader geographic sampling of populations and a greater portion of the genome is necessary to better evaluate the degree to which contemporary divergence between lineages is associated with recent founder effects and genetic isolation or evolutionary adaptation. © 2021 The Wildlife Society 相似文献
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Megan Willie Daniel Esler W. Sean Boyd Timothy Bowman Jason Schamber Jonathan Thompson 《The Journal of wildlife management》2020,84(1):161-171
Coastal regions on the Pacific north coast of North America provide important wintering habitat for many species of sea ducks. Although winter range and habitat preferences are well described for most species, fidelity to coastal wintering sites is generally undocumented. Fidelity is an important factor necessary for understanding interactions with coastal developments and activities and corresponding management strategies. We used data from Barrow's goldeneyes (Bucephala islandica), a sea duck that winters predominantly in nearshore habitats along the Pacific north coast, to investigate inter-annual fidelity to, and intra-annual fidelity within, coastal wintering sites. Between 2006 and 2015, we marked goldeneyes on breeding, molting, and wintering sites with satellite transmitters. We retained 4,931 locations in coastal habitats from 221 goldeneyes across 4 coastal regions for our analyses. These birds demonstrated high inter-annual fidelity to coastal wintering sites; 75% of selected wintering sites were within 29 km of sites used the previous winter. Inter-annual fidelity to wintering sites was similar between sex and age classes but differed by coastal region. Goldeneyes from southcentral Alaska, USA, expressed greater inter-annual fidelity relative to birds from northern or southern British Columbia, Canada, and southeast Alaska. Goldeneyes also expressed high intra-annual fidelity within wintering sites, with 75% of individuals averaging within-season movements of ≤9 km. Intra-annual fidelity was lesser for female than male goldeneyes but did not differ between hatch-year and after-hatch-year birds. We found regional variation in intra-annual fidelity, with goldeneyes from southcentral Alaska expressing greater intra-annual fidelity compared to birds from other regions. High inter- and intra-annual winter site fidelity by Barrow's goldeneyes suggests that, at a population level, habitat use is predictable and can be used to inform risk assessment or to evaluate factors affecting habitat choice. Also, low dispersal among wintering sites suggests that recovery from population perturbations, whether caused by natural or anthropogenic events, will be protracted. © 2019 The Wildlife Society. 相似文献
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ABSTRACT Factors affecting winter survival may be key determinants of status and population trends of seabirds, but connections between breeding sites and wintering areas of most populations are poorly known. Pelagic Cormorants (Phalacrocorax pelagicus; N= 6) surgically implanted with satellite transmitters migrated from a breeding colony on Middleton Island, northern Gulf of Alaska, to wintering sites in southeast Alaska and northern British Columbia. Winter locations averaged 920 km (range = 600–1190 km) from the breeding site. Migration flights in fall and spring lasted ≤5 d in four instances. After reaching wintering areas, cormorants settled in narrowly circumscribed inshore locations (～10‐km radius) and remained there throughout the nonbreeding period (September– March). Two juveniles tagged at the breeding colony as fledglings remained at their wintering sites for the duration of the tracking interval (14 and 22 mo, respectively). Most cormorants used multiple sites within their winter ranges for roosting and foraging. Band recoveries show that Pelagic Cormorants in southern British Columbia and Washington disperse locally in winter, rather than migrating like the cormorants in our study. Radio‐tagging and monitoring cormorants and other seabirds from known breeding sites are vital for understanding migratory connectivity and improving conservation strategies for local populations. 相似文献
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Eric C. Lofroth Richard D. Weir Larry R. Davis Ingebjorg Jean Hansen 《The Journal of wildlife management》2023,87(1):e22315
Fishers (Pekania pennanti) are a forest-dependent carnivore of conservation concern in British Columbia, Canada. Ecological, spatial, and genetic evidence suggests that there are 2 distinct populations (Boreal and Columbian) that occur in forests at low to moderate elevations in the boreal and central interior regions of the province. In British Columbia, fishers occur at low densities relative to other parts of their range in North America, are trapped for their fur, and are sensitive to habitat change. Despite these factors, little demographic information exists to assist with management decisions for these populations. We collated and analyzed survival and reproductive data from 100 radio-tagged fishers from 5 independent studies conducted between 1990 and 2012 in British Columbia: 2 in the Boreal population, and 3 in the Columbian population. We also collated litter size data from 1 den box study and a translocation project of fishers from the Columbian population. Annual survival rates were not significantly different between the populations or between males and females; however, adult survival rates were higher than subadults (0.79 and 0.63, respectively). Subadult females had significantly lower survival rates than other sex or age classes. Reproductive rates were significantly different between the 2 populations (denning rate = 0.54 [Columbian], 0.82 [Boreal];
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KELLY K. HASTINGS TOM S. GELATT JAMES C. KING 《The Journal of wildlife management》2009,73(7):1040-1051
ABSTRACT Steller sea lion (Eumetopias jubatus) pups (n = 366) were hot-branded at Lowrie Island, Southeast Alaska, USA, in June 2001 and 2002 for vital-rates studies. To assess potential mortality following branding, we estimated weekly survival to 12 weeks postbranding using mark-recapture models. Survival estimates ranged from 0.984/week to 0.988/week, or 0.868 over the 12-week period; varied little with sex, year, and capture area; and were higher for larger than smaller male pups and unexpectedly lower for larger than smaller female pups. Inclusion of resights at 1–3 years of age prevented a −4.5% bias in cumulative survival to 12 weeks postbranding by accounting for pups that survived but permanently emigrated from Lowrie Island during the 12-week survey. Data from double-marked pups (i.e., branded and flipper-tagged) indicated the low brand-misreading probability of 3.1% did not bias survival estimates. Assuming survival differences between the first 2 weeks postbranding and later weeks were due entirely to the branding event, potential postbranding mortality of branded pups attributable to the branding event was 0.5–0.7%, or one pup for every 200 marked. Weekly survival of branded pups was nearly identical to estimates from a control group of undisturbed, unbranded pups born to 10–11-year-old branded adult females in 2005 (0.987–0.988/week) and similar to pup survival estimates from other otariid studies. Available data did not indicate substantial mortality to 12 weeks postbranding resulting from the branding disturbance, suggesting branding of Steller sea lion pups can be used effectively for investigations of population declines without significantly affecting population health or study goals. 相似文献
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Chloe A. Wright Ian T. Adams Patrick Stent Adam T. Ford 《The Journal of wildlife management》2020,84(8):1457-1472
In many parts of North America, deer (Odocoileus spp.) have adapted to live in urban areas and are a source of negative human-wildlife interactions. Management strategies such as culling, immunocontraceptives, sterilization, and translocation have been implemented to manage urban deer populations. In the East Kootenay region of southern British Columbia, urban mule deer (Odocoileus hemionus) populations have been increasing, whereas non-urban mule deer populations have decreased. In 2014 a non-urban mule deer research project began in the area and in 2016 an urban deer translocation trial was approved in the same region. We fit 121 non-urban deer with global positioning system (GPS)-collars and translocated 135 urban mule deer to non-urban areas, of which 57 were fit with GPS-collars. We tested if annual survival between urban translocated (i.e., translocated) and non-urban deer differed, and if translocated deer survival increased in subsequent years after translocation. We also determined if age, body condition, release site, capture area and distance between capture and release sites affected translocated deer survival. We evaluated if translocated deer exhibited different movement behaviors than non-urban deer by comparing probability of migration, maximum net displacement, home range size, and probability of crossing a paved road. Finally, during our study we observed some translocated deer return to a municipal area after translocation and assessed if any covariates such as age, release site, or capture city could help predict this behavior. Annual survival of translocated deer was 0.48 and was significantly lower than survival of non-urban deer, which was 0.77. We observed 20 of 57 collared translocated deer return to a town after translocation. Translocated deer had larger net displacements and larger seasonal home range sizes than non-urban deer. Non-urban deer were more likely to migrate than translocated deer and crossed fewer paved roads than translocated deer. The management effectiveness of translocation to reduce urban deer densities is mixed because annual survival of translocated deer may be lower than may be acceptable to some stakeholders. Additionally, some translocated deer returned to an urban area, and the large distances traveled by deer after translocation may unintentionally spread disease. © 2020 The Wildlife Society. 相似文献