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Nest parasitism by Brown-headed Cowbirds (Molothrus ater) can negatively affect host populations. Landscape-scale factors, such as proximity to residential areas, equestrian riding stables, and grazing allotments, can affect the risk of nest parasitism as well as the abundance of Brown-headed Cowbirds, Recent increases in residential and recreational development along with a reduction in grazing allotments in the northern Sierra Nevada provide an opportunity to reevaluate factors that influence frequency of nest parasitism by Brown-headed Cowbirds, Frequency of nest parasitism increased as the distance to the nearest residential center and distance to the nearest equestrian riding stable decreased. Similarly, Brown-headed Cowbird abundance was negatively correlated with distance to the nearest residential center and distance to the nearest equestrian stable. To reduce the risk of nest parasitism, efforts should be devoted to (1) reducing further residential development at the wildland—urban interface and (2) educating landowners about bird feeders, which frequently attract Brown-headed Cowbirds.
Notiosorex shrews (Soricomorpha; Soricidae) have a fossil history that extends to the Miocene (i.e., mid-Hemphillian), In the intervening 6.69 million years, N. repenningi, N. jacksoni, and what heretofore was considered N. crawfordi existed with varying degrees of overlap in occurrence timewise and in geographic distribution in areas of the southwestern United States and northern Mexico. Examination of unusually small fossil specimens of Notiosorex indicated the presence of another species referable to this genus present in late Pleistocene- (i.e., early Wisconsinan) to Holocene-aged deposits. Based on statistical analyses, these specimens were as distinct from any of the other fossil or extant species of Notiosorex as any other pair of species within the genus. I referred these specimens to the new species N. harrisi. Analyses also indicted fossils heretofore considered N. crawfordl were equally distinct from other forms of Notiosorex. I referred them to the new species N. dalquesti. Individuals referred to the fossil species of Notiosorex range in size from the smaller N. harrisi, to N. dalquesti, to N. jacksoni, to the larger N. repenningi. This size differential could be related to changing climatic conditions with the concomitant ecological succession that occurred, which provided a driving force for speciation within the genus.
The changing climate and unique morphological and physiological adaptations allowed fossil taxa of Notiosorex to expand their distributions into areas subsequently less suitable for other forms of shrews, Present-day notiosoricini shrews occur throughout much of the southwestern United States and northern Mexico in a variety of habitats in association with rough, rocky terrain. Thus, if climate, even indirectly, was the driving force for speciation among fossil taxa of Notiosorex, other forces must have acted on the extant species N. cockrumi, N. crawfordl, N. evotis, and N. villai.
We investigated the present effects from a 10-year-old wildfire on leaf litter breakdown rates in 3 head-water streams in central Idaho. These systems experienced a massive debris flow one year after the fire. Based on soil instability and burn patterns, we identified 3 stream conditions; unburned, burned only, and burned/scoured. We placed leaf bags containing willow leaves (Salix sp.) in each stream type and removed bags at various time intervals until all bags were collected 100 days after their introduction. Leaf material was dried and weighed, and decay rate coefficients were calculated. Macroinvertebrates colonizing the bags were enumerated and identified, and selected taxa were placed into trophic groups. We found that the unburned stream had the fastest leaf litter breakdown rate, the lowest level of incident light reaching the stream, and the largest amount of benthic organic matter. The burned/scoured stream was nearly opposite in all respects. Numbers of 2 detritivore invertebrate taxa, Serratella tibialis and Zapada oregonensis, were highest in the unburned stream but lowest in the burned/scoured stream. A third taxon, Baetis sp., showed the opposite relationship. Presence of predatory invertebrates did not affect detritivore abundance or leaf decay rate in the bags, Our research suggests that recovery response variables of some stream systems may not have returned to prefire levels even a decade after the initial wildfire. In this study, the recovery of our streams appears to be connected to the return of the riparian zone, though fire-induced debris flows may slow or alter final recovery of the stream system.
Environmental indicators from lake sediments provide excellent opportunities to improve understanding of forest disturbance processes and corresponding changes in forest composition. Our research provides a methodology for assessing recent, historic, and prehistoric disturbances using lacustrine sediment records, We collected sediment cores from Blue Lake, a small subalpine lake on the Wasatch Plateau in central Utah. These cores record environmental changes caused by both spruce beetle (Dendroctonus rufipennis Kirby) and human (logging and livestock grazing) modification, We observed deteriorated insect remains in the lake sediments, These remains correspond temporally with a historic spruce beetle outbreak, though alkaline conditions in the lake water may have inhibited preservation of bark beetle remains. Pollen data reveal that despite the unprecedented level of mortality among Engelmann spruce (Picea engelmannii Parry ex Engelm.) resulting from the spruce beetle epidemic, logging activities subsequent to Euro-American settlement appear to be the most severe disturbance to the Blue Lake watershed over the last 750 years.
The pygmy rabbit (Brachylagus idahoensis) is a secretive, obligate sagebrush-steppe resident of the Intermountain West and is one of two rabbits in North America that digs its own burrows. Although the pygmy rabbit has a recorded home range of 0.21–67.9 ha in relatively high sagebrush cover (21%–36%), they spend much of their time within 30–100 m of a burrow system. Due to big sagebrush cover in preferred habitat and the secretive behavior of pygmy rabbits, it is often difficult to study this leporid through direct observation. We used remote cameras to document pygmy rabbit activity at burrow systems in south central Utah from 2006 to 2008. We analyzed photographs from remote cameras for daily and seasonal patterns of activity. Our results suggested that time of day and season were important influences on activity level, while year and site were less so. Pygmy rabbits were active during all time periods of the day, but the greatest activity occurred in the morning, except during winter. Numerous other species were recorded by remote cameras, including other leporids, birds, rodents, reptiles, and terrestrial predators. Remote cameras are a valuable tool in understanding pygmy rabbit behavior, in addition to confirming rabbit presence in areas of interest.
The mountains of north central Washington contain a variety of habitat types, from shrubsteppe to high alpine meadows. While native bee surveys of some surrounding areas like the Columbia Basin are fairly complete, little work has been done in the mountains of north central Washington to document the diversity of bees found therein. We conducted a survey of native bees in the Tonasket Ranger District of the Okanogan-Wenatchee National Forest during summer 2004. Collections yielded a diverse bee fauna (140 species in 24 genera) visiting diverse floral elements (57 plant species in 18 families). These preliminary data suggest that a rich bee fauna exists in the Okanogan Basin and surrounding mountains.
In most populations of mountain goats (Oreamnos americanus), mineral lick use is an essential part of the ecology of the species. In many areas, the distribution and use of licks in the landscape is poorly known, rendering planning for resource development difficult, We examined lick use by 28 GPS radio-collared mountain goats in 2 study areas in southeastern British Columbia during 2004–2005, Viewing collar-location movements on digital orthophotos, we assumed goat use of 6 previously known and 10 suspected mineral licks. Field visits verified that 9 of the 10 suspected sites were mineral licks, Thirteen of the 1.5 licks used by collared goats were within forests with commercial harvesting potential. All but 3 of the licks were ≤600 m from the closest logging block, and 5 licks were <100 m away, Number of annual visits to licks by individual goats ranged from 0 to 9. Goats often moved considerable distances (up to 17.3 km) to visit licks. Most visits by males occurred between early May and late June (median 9 June), and most visits by females occurred between early June and mid-July (median 21 June). Mean time spent at licks on each visit was 1.5 days for females and 1.6 days for males. Most of the licks were characterized by numerous cavities dug under trees (which we term “lick trees”). Using GPS collars, we were able to collect data on lower-elevation mineral licks not previously known to researchers.
We evaluated the feasibility of using passive integrated transponder (PIT) tags to mark and track individual shorthead sculpins (Coitus confusus). We implanted PIT tags in 80 shorthead sculpins in 2 size categories (60–80 mm and 81-106 mm total length) and in 1 of 2 locations (subcutaneous along the spinous dorsal fin or in the body cavity). We evaluated tag retention, sculpin survival, and net-avoidance behavior for 29 days. We observed no mortality directly attributable to PIT-tag injection at either tagging location. We observed a 38.8% loss rate of dorsal tags and a 2.5% loss rate of body-cavity tags. No change in net-avoidance behavior was observed. We released 97 PIT-tagged sculpins into an artificial stream and monitored them with 3 stationary and 1 portable antenna. Sixty sculpins were detected at least once, and 18 sculpins were detected multiple times with the portable antenna. These results indicate that PIT-tagging within the body cavity is a feasible method for marking and tracking individual shorthead sculpins.
The deserts of southern California house a diverse and unique insect fauna. Velvet ants (Hymenoptera: Mutillidae) are common in these deserts. Velvet ants are important to ecosystem health, particularly in desert environments, because they are parasitic on the bees and wasps that help maintain overall ecosystem function. The goal of this study was to measure velvet ant diversity across the deserts of southern California, We made preliminary collections from 10 sites in a variety of areas in the western Sonoran Desert (Colorado Desert), the Mojave Desert, and the Great Basin Desert. We measured β-diversity using Sørensen's similarity index to compare velvet ant richness and relative abundance between different sites. To determine how accurate our similarity estimates were, and to gain an understanding of actual velvet ant diversity, we also compared velvet ant richness of 2 sites (Algodones Sand Dunes and Deep Canyon) using data obtained from the examination of museum specimens borrowed from over 12 museums across the West, Comparisons of velvet ant faunas between sites revealed low similarities (0.167–0.75 species richness only; 0.022–0.67 both abundance and richness), Low similarity values indicate that a rich velvet ant fauna exists in the deserts of southern California.
Obtaining timely and accurate assessment of sage-grouse (Centrocercus spp.) chick survival and recruitment is an important component of species management and conservation. We compared the effectiveness of walking, spotlight, and pointing-dog surveys to detect radio-marked and unmarked chicks within broods of radio-marked hens in Utah. Walking surveys detected 72% of marked chicks, while spotlight and pointing-dog surveys detected 100% and 96%, respectively. We found no difference between spotlight and pointing-dog counts in number of marked and unmarked chicks detected (P = 0.57). Spotlight counts were slightly more time efficient than pointing-dog surveys. However, spotlight surveys were nocturnal searches and perceived to be more technically arduous than diurnal pointing-dog surveys. Pointing-dog surveys may offer greater utility in terms of area searched per unit effort and an increased ability to detect unmarked hens and broods.
Occurrences of mountain lions (Puma concolor) in Nebraska have been steadily increasing; however, reproductive activity in mountain lions has not been documented in the state. We present the first evidence of mountain lion reproduction in Nebraska since mountain lions recolonized the state in the early 1990s, On 28 February 2007, a spotted kitten was hit by a vehicle in northwestern Nebraska; and based on body length and weight, we estimate its age at 3.9 months. On 20 December 2008, a female mountain lion and spotted kitten were photographed in the northwestern part of the state, On 9 May 2009, a female mountain lion with a juvenile was also photographed. All records were from the Pine Ridge region of Dawes County, Nebraska, Our records suggest that mountain lions are establishing a permanent population in at least one region of Nebraska.
Lesser Prairie-Chicken (Tympanuchus pallidicinctus) populations have experienced dramatic rangewide declines (up to 92%) since settlement of the Great Plains, This decline has been attributed to changes in land-use practices, such as conversion of native rangelands to intensive agriculture and increased grazing pressure. These changes may increase the impact of interspecific competition on populations. We documented disturbance of lekking Lesser Prairie-Chickens by Ring-necked Pheasants (Phasianus colchicus). Future management and research should take into account possible impacts to Lesser Prairie-Chickens during the breeding season.
The mayfly Rhithrogena virilis was first described in 1934 by McDunnough in western Canada. Since its description, it has been recorded only once. We reared nymphs and provide descriptions and digital photos that may make identification of this species easier.
We report the first observations of the black-tailed jackrabbit (Lepus californicus) on Cerralvo Island, Baja California Sur, Mexico. Evidence suggests a self-sustaining population, Analysis of available records indicates no previous record of Lepus on the island, Introduction of the jackrabbit to the island appears to have occurred between 1960 and 1991.
In Iowa, the northern grasshopper mouse (Onychomys leucogaster) previously was known only from the northwestern part of the state. Herein, we report records of O. leucogaster from the 1970s and 1980s that extend its distribution into west-central and southwestern Iowa. These records may represent dispersal movements into these parts of Iowa by southward movements from populations in northwestern Iowa or they may represent eastward movements of individuals from Nebraska prior to channelization of the Missouri River.
The discovery of Draba pennellii Rollins and D. pedicellata (Rollins & R.A. Price) Windham var. pedicellata, both previously known only from Nevada, is reported here from the Deep Creek Mountains of western Utah. The documentation of significant populations of D. pennellii and D. pedicellata var. pedicellata in Utah is important for accurate botanical inventories and floristic studies in both Utah and Nevada, New distribution records for D. kassii S.L. Welsh, D. novolympica Payson & St. John, and Hackelia ibapensis L.M. Shultz & J.S. Shultz are described, and the significance of these range extensions and new populations is discussed.
Climbing behavior is poorly documented in skunk species, with the exception of the genus Spilogale. Herein we describe 2 cases of climbing behavior in the American hog-nosed skunk (Conepatus leuconotus): one in Colima, Mexico, and another in west central Texas, USA. In both cases, a male climbed over 5 m into oak trees when pursued by humans. Climbing as an escape behavior in hog-nosed skunks has not previously been reported.
We describe observations of black-tailed prairie dogs (Cynomys ludovicianus) emerging aboveground at night, apparently in response to wild-born and captive-born black-footed ferrets (Mustela nigripes) in South Dakota and New Mexico, respectively, We also discuss other similar observations accumulated on black-tailed prairie dog colonies as well as observations of white-tailed prairie dogs (Cynomys leucurus) making nighttime movements, apparently in response to pre-reintroduction ferrets in Wyoming. Our observations suggest that, in addition to documented daytime defenses against ferrets, prairie dogs reduce vulnerability to predation by ferrets by using evasive movements at night.
We report the first records of the western gray squirrel (Sciurus griseus) from Modoc County and eastern Lassen County in northeastern California. Specimens from Modoc County represent the first records of the species from the Great Basin geographic province. We conclude that these records represent a range expansion based upon previous fieldwork that did not report the species in the region.
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