Northwestern Naturalist最新文献

{"title":"EVALUATION OF TRAWL SAMPLING FOR THREATENED EULACHON (THALEICHTHYS PACIFICUS) IN THE LOWER COLUMBIA RIVER DURING JANUARY–MARCH 2013","authors":"Jeannette E. Zamon, S. Hinton, P. J. Bentley, O. P. Langness","doi":"10.1898/1051-1733-102.3.179","DOIUrl":"https://doi.org/10.1898/1051-1733-102.3.179","url":null,"abstract":"Abstract The population of Eulachon (Thaleicthys pacificus) spawning in the Columbia River and its tributaries is thought to be the largest in the world. Eulachon historically supported indigenous, commercial, and sport harvests, but were listed as threatened under the US Endangered Species Act in 2010. This study tested the use of a small research trawl and 38-kHz echosounder to provide new, fishery-independent data for Columbia River Eulachon. During January–March 2013, we used a semi-balloon shrimp trawl and an uncalibrated 38-kHz downward-looking echosounder to sample estuarine and tidal freshwater habitats. Eulachon were present in the estuary on every sampling day. Direct mortality in the trawl was very low (<0.1%). We observed sex ratios closer to 1:1 than previously reported for the Columbia River, and trawl-caught Eulachon were longer and heavier than Eulachon caught with the same gear in the same season during 1980–1981. The largest catches occurred after 11 February 2013, when midwater estuary temperature warmed and remained above 5.5°C. Tributary spawning began in mid-March after estuary warming and continued for at least 2 wk. Observations suggested that Eulachon occurred in low densities and remained dispersed in deeper waters of the estuary for at least 2 mo before upstream migration. The estuary may therefore serve as an important staging area prior to upstream migration and subsequent spawning. Catch data and qualitative acoustic images suggest that a combination of trawl and acoustic surveys could provide direct estimates of adult biomass. If Eulachon populations are to recover from the threat of extinction, additional data will be needed to resolve uncertainties regarding spawner condition, adult spawning-stock biomass, and variation in run timing relative to river and estuary conditions. We recommend implementation of systematic surveys for adult Eulachon in the Columbia River to further understand how environmental factors drive variation in run size and run timing for this species.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125069300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HIGH PREGNANCY RATES IN TWO-YEAR-OLD WILD HORSES","authors":"Lisa Grant, Robert N. Sharp, P. Griffin, Julie Weikel, L. Pielstick","doi":"10.1898/1051-1733-102.3.252","DOIUrl":"https://doi.org/10.1898/1051-1733-102.3.252","url":null,"abstract":"Abstract In November 2018, we screened 315 feral Horse mares via veterinary rectal palpation and trans-rectal ultrasound, approximately 1 mo after their capture and removal from the Warm Springs herd management area in Oregon. We documented a pregnancy rate (58.3%) in 2-y-old mares that was nearly 3 times higher than previously published results. For 1-y-old mares (10.8% pregnant), and for mares pooled over all ages (64.4% pregnant), pregnancy rates were within the range of pregnancy rates reported from other feral Horse populations. High pregnancy rates in 2-y-old mares could contribute to higher than expected herd growth rates in feral Horses.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127245294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EXTRAORDINARY PREVALENCE AND INTENSITY OF A PARASITIC NEMATODE IN TROUT AND WHITEFISH FROM THE DESCHUTES RIVER","authors":"J. Bowerman, Laura Trunk","doi":"10.1898/NWN20-30","DOIUrl":"https://doi.org/10.1898/NWN20-30","url":null,"abstract":"Abstract In the spring and summer of 2020, we found cysts of the nematode Eustrongylides spp. in Brown Trout (Salmo trutta), Rainbow Trout (Oncorhynchus mykiss), and Mountain Whitefish (Prosopium williamsoni) in the Deschutes River. The prevalence and maximum intensity of infection exceeded the range of published accounts for Eustrongylides spp. across a wide range of species. Because the 1st intermediate host is likely to be a tubificid worm, also known as a sludge worm or sewage worm, this exceptional prevalence of Eustrongylides spp. infection raises questions about conditions in the river that may be contributing to the high infection rate in fish.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114818301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DIET COMPOSITON OF FISHERS (PEKANIA PENNANTI) REINTRODUCED ON THE OLYMPIC PENINSULA, WASHINGTON","authors":"P. J. Happe, Shelby H Pace, L. Prugh, K. Jenkins, J. Lewis, J. Hagar","doi":"10.1898/NWN20-08","DOIUrl":"https://doi.org/10.1898/NWN20-08","url":null,"abstract":"Abstract Knowledge of diet composition can inform management strategies and efforts to recover endangered carnivore populations in vacant portions of their historic ranges. One such species, the Fisher (Pekania pennanti), was extirpated in Washington State prior to any formal documentation of its food habits in the coastal coniferous forests of western Washington. Fisher recovery efforts in Washington, based on translocating Fishers from extant populations, have been ongoing since 2008, beginning with the release of 90 Fishers on Washington's Olympic Peninsula from 2008 to 2010. We collected fecal samples or digestive tracts from 13 Fishers opportunistically on the Olympic Peninsula from 2009 through 2013. Subsequently, we identified the species composition of each sample's contents to determine the primary foods consumed by the reintroduced Fishers. Fisher diets were diverse and dominated by mammalian prey. Contents of feces and digestive tracts of Fishers were composed primarily of Snowshoe Hare (Lepus americanus) remains, followed by lesser proportions of Mountain Beavers (Aplodontia rufa), Northern Flying Squirrels (Glaucomys sabrinus), Douglas Squirrels (Tamiasciurus douglasii), Southern Red-backed Voles (Myodes gapperi), shrews (Sorex spp.), and unidentified ungulate species. The diet of Fishers comprised species that occur across a wide range of land uses and management prescriptions, including previously logged forests and mature forests that have been set aside for retention of old-growth forest characteristics. Additional study of prey abundance and Fisher foraging behaviors related to structural habitat characteristics across a gradient of land uses would provide useful insights for enhancing the effectiveness of conservation efforts to benefit Fishers in Pacific Northwest coastal forests.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134213858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MISDIRECTED AMPLEXUS BETWEEN A PACIFIC TREEFROG (PSEUDACRIS REGILLA) AND A WESTERN TOAD (ANAXYRUS BOREAS) IN A NORTHERN CALIFORNIA UPLAND","authors":"J. Alvarez, Elizabeth Lopez, Tara L. Collins, Angelique Herman, Jennifer Jelincic, Marina L Olsen, Brian Piontek, Alicia I Ringstad, Jeffery T. Wilcox","doi":"10.1898/NWN20-27","DOIUrl":"https://doi.org/10.1898/NWN20-27","url":null,"abstract":"Abstract Misdirected amplexus has been reported between conspecifics, congeners, between different amphibian families, and between amphibians and non-amphibian objects. We observed misdirected amplexus between a Pacific Treefrog and a Western Toad, wherein the treefrog amplexed the toad's leg. These types of events can result in reproductive interference and have also been considered an evolutionary trap for some species.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"363 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124979486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BATS TRANSIT AND FORAGE OVER NEARSHORE ENVIRONMENTS IN THE NORTHERN GULF OF ALASKA","authors":"T. Mullet, Paul A. Burger, Kelsey Griffin","doi":"10.1898/NWN20-09","DOIUrl":"https://doi.org/10.1898/NWN20-09","url":null,"abstract":"Abstract We present evidence of bats transiting and foraging over the ocean along nearshore environments in the northern Gulf of Alaska. Acoustic surveys were conducted on 2 sea-based vessels that anchored overnight off the coasts of 2 national parks (July–August 2019). We documented Little Brown Myotis (Myotis lucifugus) transiting and foraging over the ocean at 14 sites within the nearshore zone at an average off-coast distance of 298 m (s = 154). Little Brown Myotis inhabiting coastal habitats in Alaska are utilizing nearshore environments similar to Vespertilionid bats in the North Atlantic.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121172358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PHOTOGRAPHIC EVIDENCE OF HETEROSPECIFIC COPROPHAGY IN AMERICAN PIKA","authors":"P. Ross Gorman","doi":"10.1898/nwn20-31","DOIUrl":"https://doi.org/10.1898/nwn20-31","url":null,"abstract":"Abstract An observation of an American Pika collecting Yellow-bellied Marmot scat to add to its winter food cache is reported. This unusual behavior was observed in Yellowstone National Park, Wyoming, USA and was documented photographically.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126287947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DIRECT OBSERVATIONS OF A WOLVERINE SCAVENGING AT AN ACTIVE GRAY WOLF KILL SITE","authors":"Cody F. Wallace, J. Golla, M. L. Allen","doi":"10.1898/NWN20-13","DOIUrl":"https://doi.org/10.1898/NWN20-13","url":null,"abstract":"Abstract Scavenging carrion is an important source of nutrition for Wolverines (Gulo gulo), which are facultative scavengers. Other large carnivores, particularly Gray Wolves (Canis lupus), may compete with and exclude Wolverines from carrion or pose a risk of death or injury to Wolverines attempting to consume these resources. We used a video-camera trap to document a Wolverine scavenging an Elk (Cervus elaphus) being actively consumed by a Gray Wolf in Idaho. The Wolverine investigated the kill, ate, scent marked, and removed pieces of the carcass to cache at other sites. Between the 2nd and 3rd visit by the Wolverine, a wolf returns to feed at the kill. These observations establish that Wolverines do not necessarily avoid kills when Gray Wolves are present and that species interactions are more complex than generally thought.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123444831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RECURRENT INGESTION OF GRIT BY COMMON NIGHTHAWKS (CHORDEILES MINOR)","authors":"A. Burger","doi":"10.1898/NWN20-19","DOIUrl":"https://doi.org/10.1898/NWN20-19","url":null,"abstract":"Abstract Grit ingestion is widespread among birds, as an aid for grinding up food and as a dietary supplement of calcium, but is less common among insectivores, especially aerial feeders like nightjars (Caprimulgidae). I report recurrent visits by Common Nighthawks (Chordeiles minor) to a gravel driveway in British Columbia at dusk over a 4-y period. These ground visits were highly consistent (nighthawks landed during 93% of 72 dusk watches) and visits were highly concentrated both in time (95% of time on the ground between 10 and 57 min after sunset) and space (91% of the birds' time was spent in 2 areas comprising only 31% of the visible study site). Birds pecked at the ground in 97% of 198 focal-animal watches. In 43 visits the nighthawks picked up or swallowed some item; in 24 cases this was a small piece of gravel and no other items were identified. Surveys of ground arthropods in the study area over 3 y showed that potential prey were sparse (mean <2 insects m–2) and the most common insects were unsuitable prey (tiny 3-mm ants). I conclude that the only reason for the nighthawks to consistently visit this gravel area was to ingest grit. The gravel ingested was crushed limestone, which might support a calcium uptake hypothesis. Grit ingestion, occurring within a restricted dusk period, might not explain why nightjars often sit on gravel roads at night, which is a major source of mortality for several species. Information on ground behavior in Caprimulgidae is important for understanding their mortality risks and conservation.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127590689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LATE PLEISTOCENE PINE MARTEN (MARTES; MUSTELIDAE) FROM THE BLACK HILLS, SOUTH DAKOTA","authors":"J. Mead, Sandra L. Swift, C. Jass, Jeffrey I Meyers, Sharon E Weaver","doi":"10.1898/NWN20-20","DOIUrl":"https://doi.org/10.1898/NWN20-20","url":null,"abstract":"Abstract Two species of pine martens (Mustelidae, Martes americana, M. caurina) inhabit northern North America, with both species overlapping their distributions in the northwest of the USA and Canada. One extinct form (M. nobilis), larger than extant species, is known predominantly from Late Pleistocene cave deposits in the Intermountain West. Here we report on the skeletal remains of pine marten recovered from 2 caves in Wind Cave National Park, Black Hills, southwestern South Dakota. Only introduced marten populations occur in the region today, highlighting the significance of the records for understanding the biotic history of the region. One complete skeleton of Martes recovered from Wind Cave radiocarbon dates to approximately 11,100 calibrated years BP, whereas the other fossil remains from the nearby Persistence Cave date to between 12,000 and 42,000 y old based on associated 14C dates. These remains represent the 1st fossil record of Martes from the Black Hills. Both forms of recovered pine martens, characterizing extinct and extant morphologies, were recovered in the caves but as yet are not understood to be sympatric in the local community.","PeriodicalId":142406,"journal":{"name":"Northwestern Naturalist","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114437565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}