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1.
In northern areas of their expanded range, information on Merriam's turkeys ( Meleagris gallopavo merriami ) is lacking, specifically pertaining to wintering behavior and factors associated with winter habitat selection. Forest managers need detailed quantification of the effects of logging and other management practices on wintering habitats needed by Wild Turkeys and other wildlife. Therefore, we examined winter habitat selection patterns within ponderosa pine ( Pinus ponderosa ) forests and determined factors associated with use of farmsteads by Merriam's turkeys in the southern Black Hills, South Dakota. We radio-marked 86 female Merriam's turkeys (70 adults and 16 yearlings) and monitored them during winter (1 December–31 March), 2001–2004. Female Wild Turkeys used recently burned pine forest less than expected but selected farmsteads and stands of mature ponderosa pine ( 22.9 cm diameter at breast height [DBH] trees) for foraging sites. Within forests, female Wild Turkeys selected foraging sites with less understory vegetation and visual obstruction, and larger-diameter ponderosa pine. Ponderosa pine seed abundance varied among years, and pine seeds were most abundant in stands of 30–35 cm DBH with basal area of 22–28 m2 ? ha–1. Abundance of pine seeds may have influenced use of farmsteads by Wild Turkeys, more so than ambient temperatures or snow depth. In the southern Black Hills, management should emphasize open- to mid-canopy and mature-structural-stage pine stands, where seed production was greatest. During winters when mast from pine is unavailable, farmsteads likely provide nutritional supplementation and may be important for maintaining Merriam's turkey populations.  相似文献   

2.
Observational data from spring and fall 1996 and spring 1997 for the region near Mulegé, Baja California Sur, Mexico, are summarized in tabular form. In addition, new or noteworthy data for 17 species are annotated to provide clarification of previously published records. A uniquely plumaged bird, too far south for a female American Robin ( Turdus migratorius ) in basic plumage and too far north for the endemic ""San Lucas"" Robin ( Turdus migratorius confinis ) and intermediate in coloration between the two, was recorded. Range expansions are documented for several species including the European Starling ( Sturnus vulgaris ), Anna's Hummingbird ( Calypte anna ), Western Meadowlark ( Sturnella neglecta ), White-faced Ibis ( Plegadis chichi ), and White-fronted Goose ( Anser albifrons ). Lease Grebes ( Tachybaptus dominicus ), a species of concern which is apparently declining in numbers, and Belding's Yellowthroat ( Geothlypis beldingi ) a species endemic to Baja California Sur, were observed in the freshwater marsh during all 3 study periods.  相似文献   

3.
Previous work suggested that Gambel oak seedlings are rare in the northern parts of its range in Utah where summer rainfall is relatively low but should be abundant in southern parts of the range where summer rainfall is usually high. Gambel oak grades from a relatively minor component of a ponderosa pine/mixed conifer assemblage in the south to a virtually monotypic formation in the north, where it exists as long-lived clones.   Quadrat analysis in Arizona and New Mexico, within the oak zone, revealed a seedling density ranging from 120 to 1320 per hectare. We found a significant tendency of seedlings to be located on the NE (cool, shady) side of sheltering objects in the environment. Mature ponderosa pine ranged in density from ca 40 to 500 stems per hectare, whereas mature Gambel oak ranged from ca 10 to 20 genets per hectare with ca 1 to 7 ramets per clone. These results support our previous conclusion that Gambel oak in northern Utah probably became established as a minor component of a mixed pine/oak woodland at a time in mid-Holocene when summer rainfall was much higher than today.  相似文献   

4.
Habitat use and selection by Merriam's Wild Turkeys ( Meleagris gallopavo merriami ) in Wasco County, Oregon, was studied during 1981-82. This turkey population selectively used forested cover types (such as ponderosa pine-Douglas-fir-oak, ponderosa pine-oak) characterized by a variety of structural features, species, and age classes. The population used single species forested cover types (oak, ponderosa pine) less than expected, used nonforested cover types in proportion to their availability, and avoided forested cover types with structure simplified by logging activities. The four age and sex classes had large seasonal home ranges ( ̄x = 1,615 ha); the smallest home ranges were exhibited by adult males in winter and the largest were shown by subadult males in fall. In most instances, turkeys used cover types as they were available. We suggest that structural complexity of vegetation, both within and among cover types, is an important component of habitat for Merriam's Wild Turkeys that should be considered in the evaluation of potential release sites and in habitat management plans.  相似文献   

5.
Limber pine ( Pinus flexilis James) seeds are usually wingless but occasionally have short, stubby wings. To determine the effectiveness of these wings in slowing seed descent, rates of fall were determined before and after wing removal. A similar experiment was conducted with seeds of Himalayan blue pine ( P. griffithii McClelland), a white pine with typically long seed wings. The short wings of limber pine seeds were found to influence rate of seed fall far less than the wings of Himalayan blue pine. This is consistent with evidence suggesting that limber pine seeds are not effectively dispersed by wind but are dependent for dispersal on Clark's Nutcracker ( Nucifraga columbiana ).     相似文献   

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8.
Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} In 1973 a timber harvest of ponderosa pine ( Pinus ponderosa ) was conducted in an area southeast of Monticello, Utah, that is inhabited by Abert squirrels ( Sciurus aberti ). Abert squirrel dietary habits, foraging patterns, and population densities were compared in the timber harvest area and in an adjacent nonharvested area. Squirrel feeding patterns and preferences were visually determined by physical evidence of past feeding. Live-trapping and field-marking of animals were used to determine population density and trends in the two areas. Squirrels fed in only 26.3% of sampled plots on the timber harvest areas, while 42.7% of the uncut area plots showed use (P 50 acres) by clear-cut methods commonly employed by management agencies.  相似文献   

9.
Spermophilus brunneus is restricted to a 90 × 125-km area of west central Idaho, with two distinct (northern and southern) groups of populations within this limited range. Morphological differences in pelage length and coloration, external and cranial measurements, and bacula suggest that these groups are either very distinct subspecies or species. We used starch-gel electrophoresis to estimate the amount of genetic differentiation accompanying these morphological differences by assaying genetic variation at 31 loci in the two geographic groups. Fifteen loci were polymorphic (13 in the northern group, 12 in the southern), and mean heterozygosity (H) was high (12.3% northern and 10.8% southern). Nei's genetic distance (0.057) is in the range usually associated with subspecific differences. However, Jaccard's association coefficient (0.893) is about the same as that found between several ground squirrel taxa currently recognized as species. The high levels of heterozygosity suggest that S. brunneus is a neoendemic rather than a paleoendemic species.  相似文献   

10.
Brewer's Sparrows ( Spizella breweri ) have two song types--a ""short"" song that has 1 to 3 trill types and a ""long"" song that has 5 to 10 or more trill types. I describe the short song and examine patterns of individual and geographic song variation from 15 sites on the Snake River Plain in southern Idaho. Territorial males sang the short song regularly during the breeding season. Two-trill song types comprised 72.9% of all song types, with 3-trill types (18.8%) and 1-trill types (8.2%) less frequent. Over 90% of the males sang their song type(s) essentially without variation. Many trill types appeared most often in only 1 of 3 possible song positions, i.e., 1st, 2nd, or 3rd trill. Trill types that occurred in different song positions differed in syllables per second, trill and syllable duration, and frequency variables. First trill types were more variable than 2nd or 3rd trill types. There was no evidence that birds at sites closer together shared more trill types or pairs of trill types than those farther apart. There was no tendency for territorial neighbors to sing similar song types. Brewer's Sparrows' small territories, dense populations, and apparently high rate of annual turnover may mediate against the evolution of song sharing or vocal dialects.  相似文献   

11.
Burrow diameters of five small mammal species, Townsend's ground squirrel ( Spermophilus townsendii ), Wyoming ground squirrel ( S. elegans ), Ord's kangaroo rat ( Dipodomys ordii ), montane vole ( Microtus montanus ), and deer mouse ( Peromyscus maniculatus ), were examined. Burrow cross sections were noncircular for all species with horizontal diameters 1.2-1.6 times wider than vertical diameters. Montane vole and deer mouse burrows were the smallest diameter, burrows of Wyoming and Townsend's ground squirrels were the largest, and kangaroo rat burrows were intermediate. Soil bulk density and texture significantly affected burrow diameters of montane voles and deer mice but not the other three species.  相似文献   

12.
Southwestern Idaho desert shrub-bunchgrass rangeland is being invaded by fire-prone exotic annuals that permanently dominate the landscape following wildfires. This study was undertaken to describe diets of Townsend's ground squirrels ( Spermophilus townsendii idahoensis ) at four study sites with varying degrees of exotic annual invasion to determine if the squirrels could utilize high proportions of exotic annuals in their diets. Townsend's ground squirrels were collected in March and May of 1987 and 1988, and stomach contents were analyzed using a microhistological technique. Grasses comprised 37-87% of Townsend's ground squirrel diets at the four sites. Native species, especially Sandberg's bluegrass ( Poa secunda ), winterfat ( Ceratoides lanata ), big sagebrush ( Artemisia tridentata ) and six-weeks fescue ( Vulpia octoflora ) constituted 7-96% (x = 47.2%) of the diet, whereas exotic species, especially cheatgrass ( Bromus tectorum ), tumbleweed ( Salsola iberica ), and tansymustards ( Descurainia spp.) made up 4-68% (x = 48.0%) of the diet. At each site 2-4 species comprised >90% of the diet. There was no apparent correlation between the importance values of exotic species at a site and their importance in Townsend's ground squirrel diets.  相似文献   

13.
From 1990 to 1992 we surveyed for Flammulated Owls ( Otus flammeolus ) in 3 areas in Idaho: Salmon National Forest (SNF), Payette National Forest and adjacent Hells Canyon National Recreation Area (PNF-HCNRA), and Nez Perce National Forest (NPNF). We also collected and summarized information on all historic and modern records of Flammulated Owls in Idaho. Flammulated Owls were detected on 65% of 68 routes (2-16 km in length) surveyed at densities ranging from 0.04 to 1.25 singing males/40 ha. Owls were detected on survey routes as early as 10 May and as late as 23 July. Mean percent canopy cover estimated at owl locations on the PNF-HCNRA and NPNF study sites ranged from 52% to 64%, while shrub cover ranged from 16% to 21% and ground cover was 39% to 49%. Our surveys and summary of distributional records indicated that Flammulated Owls occur throughout the montane forests of Idaho in old or mature stands of open ponderosa pine ( Pinus ponderosa ), Douglas-fir ( Pseudotsuga menziesii ), and stands co-dominated by those 2 species. Fire suppression and timber harvest activity in ponderosa pine forests represent 2 main threats to the species' future security in Idaho. More research on the effects of various silvicultural treatments on Flammulated Owl populations is warranted.  相似文献   

14.
Following an Ips bark beetle outbreak in 2002, mortality of ponderosa pine ( Pinus ponderosa Douglas ex C. Lawson) was evaluated in 2 study areas infested with southwestern dwarf mistletoe ( Arceuthobium vaginatum [Willd.] Presl subsp. cryptopodum [Engelm.] Hawksw. & Wiens) in the Coconino and Tonto National Forests, Arizona. A pairwise comparison of dwarf mistletoe ratings for live and dead ponderosa pines was conducted to determine whether dead ponderosa pines had higher dwarf mistletoe ratings than pines that were not attacked. In both study areas, dead ponderosa pines had significantly higher dwarf mistletoe ratings, indicating an association between the severity of dwarf mistletoe infection and susceptibility to attack by Ips spp. We suggest that the probability of ponderosa pine mortality is greater in stands severely infested with southwestern dwarf mistletoe in northern Arizona.  相似文献   

15.
The present distribution of the Mexican vole ( Microtus mexicanus ) is not entirely the product of post-Pleistocene forest fragmentation and extinction; recent dispersal also is indicated. Literature records further suggest that this phenomenon may reflect a general pattern of northward range expansion in many southwestern mammal species.  相似文献   

16.
Alniphagus africanus Schedl, 1963, and Hylesinus africanus Schedl, 1965, were both transferred to Hylesinopsis and thereby become junior homonyms of H. africanus (Eggers, 1933). The new name H. acaciolens is proposed as a replacement for Schedl's 1963 name and H. secutus as a new name for Schedl's 1965 name. Six species from Mexico are described as new to science, including: Hylocurus atkinsoni, H. crotonis, Monarthrum xalapensis, Pseudochramesus jaliscoensis, Pseudopityophthorus durangoensis , and P. xalapae .  相似文献   

17.
Alniphagus africanus Schedl, 1963, and Hylesinus africanus Schedl, 1965, were both transferred to Hylesinopsis and thereby become junior homonyms of H. africanus (Eggers, 1933). The new name H. acaciolens is proposed as a replacement for Schedl's 1963 name and H. secutus as a new name for Schedl's 1965 name. Six species from Mexico are described as new to science, including: Hylocurus atkinsoni, H. crotonis, Monarthrum xalapensis, Pseudochramesus jaliscoensis, Pseudopityophthorus durangoensis , and P. xalapae .  相似文献   

18.
Populations of breeding Swainson's Hawks ( Buteo swainsoni ), Red-tailed Hawks ( B. jamaicensis ), and Golden Eagles ( Aquila chrysaetos ) present in 1999 were compared with populations present between 1975 and 1982 at a 129-km 2 site in north central Oregon. Populations of Red-tailed Hawks and Golden Eagles remained unchanged, but the number of Swainson's Hawks pairs increased from 15 to 17. In 1999 Golden Eagles used nests occupied between 1975 and 1982, and 7 of 31 pairs of Red-tailed Hawks used nests occupied in earlier years. No Swainson's Hawks nested in trees occupied earlier. Few changes in territorial boundaries were detected.  相似文献   

19.
The sequential effects of feeding by grass bugs ( Irbisia pacifica [Hemiptera: Miridae]) and of drought stress on the growth of 2 crested wheatgrasses (the hybrid Agropyron cristatum × desertorum and A. cristatum cv. 'Fairway') were investigated in a controlled greenhouse experiment. Growth rates of genotypes that were previously selected for resistance to grass bug feeding were not consistently greater than those of unselected genotypes when plants were exposed to bug feeding. Thus, the mechanism of resistance to bug feeding for the selected genotypes does not appear to be ""tolerance,"" i.e., rapid growth rates that allow the resistant genotypes to compensate for damage to green leaves caused by bug feeding. In addition, previous bug feeding did not exacerbate the effects of drought stress on plant growth rates; droughted plants generally had lower growth rates, independent of the presence or absence of prior bug feeding. Thus, we suspect that the selection process may have inadvertently favored green, robust plants rather than true resistance to bug feeding.  相似文献   

20.
One hundred forty-three species of Pompilidae are recorded from Colorado, slightly more than half the number occurring north of Mexico. Some of these occur principally at higher altitudes or in the northern part of the state; this group includes 5 species of Holarctic distribution. Others (such as the tarantula hawks, Pepsis ) are prevalent across the southern third of the state and range south into New Mexico and often into Mexico. Still others are widely distributed wherever there is friable soil and suitable for nesting. Certain genera are more or less restricted to preying upon certain spider taxa, while others are generalists and a few are cleptoparasites of other Pompilidae.  相似文献   

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