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1.
During 1999 and 2000 we trapped and radio-marked 156 Columbian Sharp-tailed Grouse ( Tympanuchus phasianellus columbianus ) on leks in Conservation Reserve Program (CRP, n = 73) and mine reclamation (MR, n = 83) lands in northwestern Colorado. Median spring--fall home range sizes using the 95% fixed kernal and minimum convex polygon estimators for 54 grouse were 86 ha and 61 ha, respectively. Median fixed kernal home range size did not differ between males (79 ha) and females (87 ha). Home ranges of grouse associated with CRP (112 ha) were larger than those of grouse in MR (75 ha). Directional orientation of movements from leks of capture to wintering areas was nonrandom, and there was a positive elevation gain (median = 102 m) associated with these movements. Movements did not differ between grouse captured in CRP and MR for any season but did differ between genders for the spring--fall period. Males exhibited stronger fidelity and less variation in their movements than females; 96% of males compared with only 77% of females remained within 2.0 km of their lek of capture from spring through fall. Ninety percent of females nested within 2.5 km of their lek of capture. During winter all grouse were found farther (median = 21.5 km) from lek sites than in any other season. Males remained on the breeding range longer in the fall and returned earlier in the spring than females even though they wintered similar distances away (median males = 21.5 km, median females = 21.4 km). Our findings support the 2.0-km radius used in the Habitat Suitability Index model for Columbian Sharptailed Grouse to assess nest and brood-rearing cover around leks, but not the 6.5-km radius used to evaluate winter cover.  相似文献   

2.
We observed a breeding Bald Eagle ( Haliaeetus leucocephalus ) pair nesting in a short-grass prairie and agricultural community on the southern Great Plains of the Texas Panhandle in 2004 and 2005. The nesting eagles produced 1 fledgling in 2004 and 2 fledglings in 2005. Our assessment of landcover types within a 5-km radius of the nest indicated that grasslands accounted for most of the area (90%), followed by agricultural lands (8%). Black-tailed prairie dog ( Cynomys ludovicianus ) colonies occupied 2.5% of the area, and single human residences with associated structures (i.e., barns) occupied 2.5 ha in surface area was 51 km from the nest. An analysis of regurgitated castings collected near the nest revealed a mammalian-dominated, breeding-season diet with black-tailed prairie dogs occurring in 80.9% of the castings. Other identified prey included cottontails ( Sylvilagus spp., 15.9%), black-tailed jackrabbits ( Lepus californicus , 3.2%), pronghorn ( Antilocapra americana , 3.2%), and plains pocket gopher ( Geomys bursarius , 1.6%). Bird remains were also present in 34.9% of the castings. This is the first reported successful nesting of Bald Eagles in the panhandle region of Texas since 1916; the nest is particularly unique because of its distance from any substantial body of water.  相似文献   

3.
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;} Of 42 Microtus pennsylvanicus trapped 1 km from Bozeman, Montana, 14 (33.3 percent) were infected by strobilocerci of Taenia taeniaeformis, while only one (2.1 percent) of 47 was infected at a rural site 16 km from Bozeman. The higher incidence of the primary host, domestic cats, is believed to account for the higher rate of infection near Bozeman.  相似文献   

4.
Growth rates, gestation period, litter size, reproductive age, sex ratios, and development were studied on 198 litters of Reithrodontomys megalotis megalotis (Baird). Growth was characterized by several standard skull and body measurements and was partitioned into four phases of 1 – 3, 4 – 12, 13 – 22, and 23 – 70 days. Growth was best described by measurements of tail length, ear length, and dried eye - lens weight. Reproductive activity began as early as 38 days for females and 59 days for males. The gestation period was 22 days, and the mean litter size was 3.83 (range 1 – 7). Sex ratio was 53.49 percent males to 46.51 percent females. Reproductive efficiency was 53.53 percent. The development of R. m. megalotis was very similar to that of R. m. dychei. Early breeding, postpartum estrous, year - round breeding, high reproductive efficiency, and a short gestation period contribute to a high reproductive potential in R. m. megalotis.    相似文献   

5.
Food habits of a population of the Burrowing Owl ( Athene cunicularia ) at the Idaho National Engineering Laboratory, Butte County, were studied. The 421 pellets examined yielded 2,436 prey items of at least 22 prey species. Invertebrates, largely insects, constituted 91 percent of the total prey items, but only 29 percent of the total biomass; mammals constituted 8 percent of the prey items, but 68 percent of the biomass. The prey were mostly nocturnal species; diurnal species were poorly represented.  相似文献   

6.
Two Onychomys torridus longicaudus Merriam were captured at a site 22 miles W Winnemucca, Humbolt Co., Nevada. This record extends the known range of O. torridus 165 km to the northeast.  相似文献   

7.
We surveyed 7 species of predatory birds weekly during a 12-month period (December 1992 through November 1993) in the east Mojave Desert, California. The Common Raven ( Corvus corax ) was the most frequently observed species with an average of 6.9 sightings per 100 km. Turkey Vultures ( Cathartes aura ), Red-tailed Hawks ( Buteo jamaicensis ), Loggerhead Shrikes ( Lanius ludovicianus ), American Kestrels ( Falco sparverius ), Golden Eagles ( Aquila chrysaetos ), and Prairie Falcons ( Falco mexicanus ) were seen in decreasing order of frequency of observation through the study period. Ravens, Red-tailed Hawks, Loggerhead Shrikes, American Kestrels, and Prairie Falcons were seen throughout the year. Turkey Vultures were not present during winter months, while Golden Eagles were seen only during November and December. Turkey Vultures, Red-tailed Hawks, and ravens were most numerous on agricultural lands, while Loggerhead Shrikes were most common at urban areas. Raven numbers increased with increasing number of linear rights-of-way parallel to the survey route. Perching was the most common behavior type, although Turkey Vultures and ravens were often observed soaring, flying, or standing on the ground near highways. Transmission powerline towers and telephone poles were used as perch sites disproportionately to availability.  相似文献   

8.
Maternal defensive behavior against predators may appear risky but is common in many species. Herein we describe maternal defensive behavior of mountain goats ( Oreamnos americanus ) against Golden Eagle ( Aquila chrysaetos ) predatory attempts. We found that Golden Eagles attacked goats in 1.9% of sightings ( n = 311 sightings of active Golden Eagles over 12 years) but were never successful. Mothers always defended their young against Golden Eagle attacks. Predation by Golden Eagles on young-of-the-year appears low for most ungulate species, including mountain goats. The benefits of defending offspring against eagles are likely high in ungulates, and we would therefore expect selection to favor maternal defensive behavior.  相似文献   

9.
A population of Penstemon pseudospectabilis M. E. Jones (Scrophulariaceae) on Cave Creek in Cochise County, Arizona, was used in an experimental test of reproductive fitness with three caging treatments: all flying pollinators excluded, hummingbirds excluded, and no exclusion. Twenty plants were chosen and three shoots on each used in the experiment. The flowers were 25.6 (s.d. = 1.5) mm long, the end diameter was 8.5 (s.d. = 1.0) mm, the tube opening was 6.5 (s.d. = 1.0) mm, and the greatest diameter, 75% distal from the receptacle, was 10.1 (s.d. = 0.8) mm (N= 59). Floral nectar contained 11.7% (s.d. = 2.9%) fructose, 13.8% (s.d. = 2.7%) glucose, and 74.5% (s.d. = 5.4%) sucrose (N = 74). There was some evidence, significant only for fructose, that nectar-sugar composition varies between morning and evening. Larger floral dimensions were correlated with lower sucrose and higher hexoses. Casual observation showed Xylocopa sp., small bees, flies, and hummingbirds to be visitors. There was no sign of nectar robbing. Five percent of flowers set seed with all pollen vectors excluded, 44% with hummingbirds excluded, and 63%with no exclusion. Seed set per fruit was 2 with all excluded, 23 with hummingbirds excluded, and 46 with no exclusion. Mean seed set on pollinated flowers was 60, with a range of 2 to 192. Multiple linear regression showed the fraction of fruit setting seed when hummingbirds were excluded to be related to larger flower diameters and shorter flowers. With no pollinator exclusion, fruits setting seed were related to larger diameters and nectar fructose. For seeds per fruit, multiple regression gave similar, but less clear, results. We conclude that P. pseudospectabilis is pollinated by both bees and hummingbirds, with other pollinators not to be excluded as possible contributors. We found no hard evidence of selective forces currently at work.  相似文献   

10.
We examined the mycophagy (ingestion of fungi) of squirrels of five genera and eight species in the coniferous forests of Oregon. Data from 644 dietary samples demonstrated that squirrels of all eight species are mycophagous and eat the belowground fruiting bodies of at least 26 genera of mycorrhizal fungi. Four species are primarily arboreal and active throughout the year; the other four are primarily terrestrial and hibernate during winter. Of the squirrels examined, only the northern flying squirrel ( Glaucomys sabrinus [Shaw]) is nocturnal and almost exclusively a fungivore. The flying squirrel is used to illustrate the dynamics of all the squirrels in association with hypogeous mycorrhizal fungi, nitrogen-fixing bacteria, yeast, and coniferous trees in Oregon forests because we have studied it the most. Squirrels may prove to be vital links among different processes within temperate coniferous forests.  相似文献   

11.
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   

12.
The cyclical phenomenon of soft and hard formation of feces in desert black - tailed jackrabbits ( Lepus californicus deserticola, Mearns) was investigated. Sixty - nine blacktails were shot between 0525 hours and 1508 hours over a 4 - day period. The average age was 314 days for all black - tails. The large intestine was removed and linear measurements taken. Overall length of the large intestine averaged 163.3 cm; mean length of the colon was 51.5 cm and average length of the rectum was 111.8 cm. Moisture content for soft and hard pellets averaged 79.5 percent and 74.1 percent, respectively. Protein content of soft and hard pellets averaged 45.8 percent and 14.3 percent, respectively. The black - tails began the transition from hard to soft pellets as early as 0414 hours, and nearly all had completed the reverse transition by 1508 hours. Female black - tails began both early morning and afternoon transitions significantly later than the males. Reasons for the apparent sexual partitioning are proposed.  相似文献   

13.
A survey of colony attributes and associated vertebrates on black - tail ( Cynomys ludovicianus ), Gunnison's ( C. gunnisoni ), and white - tail ( C. leucurus ) prairie dogs was made. A belt transect 1.6 km wide and 13,334 km long from Hobbs, New Mexico, to the Utah - Wyoming state line was surveyed. There were 47 colonies located (4760 ha comprising 2.2 percent) in the belt. Intercolony distances varied significantly. Three black - tail towns averaged 33 ha in area (SD = 26, range 10 – 61), II Gunnison's averaged 46 ha (SD = 43, range 16 – 150), and 33 white - tail towns averaged 125 ha (SD = 200, range 0.2 – 958). Badger activity was positively and significantly correlated to colony size and number of burrow openings on Gunnison's and white - tail towns. There were 107 vertebrate species and subspecies (one amphibian, 25 reptiles, 51 birds, 30 mammals) observed on prairie dog colonies. Results of our surveys are compared with prairie dog studies elsewhere. The role of prairie dogs and relationships to some vertebrates species are discussed.  相似文献   

14.
Scytonotus granulatus (Say, 1821) (Polydesmida: Polydesmidae), the most widely ranging polydesmid species in North America and the 4th most widely distributed indigenous continental milliped, is recorded from LeFlore and Latimer Counties, Oklahoma, and Jackson County, Alabama, the 1st records from these states. It also occurs in Logan and Independence Counties, Arkansas. The Latimer County record corresponds approximately to the terminus of the eastern forested biome and extends the distributions of the species and the genus some 255 miles (408 km) westward; along with literature records from Shawnee County, Kansas, and Cass County, Nebraska, it constitutes the western range limits. The projected overall distribution extends around 1100 miles (1760 km) east-west and 985 miles (1576 km) north-south and encompasses parts of Ontario, Québec, and 19 states, including all of Pennsylvania, West Virginia, Ohio, Indiana, and Illinois. New localities are detailed as are those from Missouri and that from Dare County, on the Outer Banks of North Carolina.  相似文献   

15.
Distribution, movements, and habitat use of 10 wild adult razorback suckers ( Xyrauchen texanus ) were examined in Lake Mohave, Arizona-Nevada, from November 1994 through July 1997. Movement rates (0.00-17.35 km d -1 ) and ranges ( x = 39 km) were similar to those for riverine populations. All study fish returned to spawning sites used in previous years, but they also visited other spawning areas. Spawning females were significantly ( P = 0.031) more active than males (480 vs. 87 m d -1 ) and moved substantial distances between spawning sites during peak reproduction (1-28 February). Fish became most active (m d -1 , km month -1 ) after spawning and moved to areas known to support higher algal production. Fish were typically within 50 m ( P 30.0 m). Adults were detected throughout the available thermal gradient (12°-30°C), but during summer typically had body temperatures between 18° and 22°C. Vertical movements within the water column showed no correlation with depth or time of day, but seasonal shifts suggest fish may regulate body temperature by seeking specific temperatures during reservoir stratification.  相似文献   

16.
A survey of terrestrial vertebrates was conducted at the Scotts Bluff National Monument (SBNM), Nebraska, to determine species composition, relative abundance, and distribution by habitat of the existing amphibians, reptiles, birds, and mammals. Various sampling methods were used to detect animal species richness and to estimate population densities. The seven major habitat types at SBNM contained 4 species of amphibians, 8 reptiles, 96 birds, and 28 mammals. The only endangered or threatened species observed was a dead bald eagle ( Haliaeetus leucocephalus ). The racer ( Coluber constrictor ) and prairie rattlesnake ( Crotalus viridis ) were the two most abundant snakes. The prairie falcon ( Falco mexicanus ) was a common raptor that nested in Scotts Bluff. Sympatric populations of mule deer ( Odocoileus hemionus ) and white-tailed deer ( Odocoileus virginianus ) appeared to be hybridizing. The riverine woodland contained the greatest number of fauna species with only 4% surface area of SBNM. Sharp-tailed grouse ( Tympanuchus phasianellus ) and pronghorn antelope ( Antilocapra americana ), absent from the Monument, are two potential native species for reintroduction.  相似文献   

17.
Summer food habits of coyotes ( Canis latrans ) were investigated on a 3100-km 2 area in central Wyoming, divided into one deer-use area and five non-deer areas. Analysis of 404 scats (fecal samples) revealed an overall average of 63 percent occurrence of native ungulates, 63 percent leporids, 46 percent rodents, 14 percent livestock, and 11 percent birds. Pronghorn ( Antilocapra Americana ) was the ungulate most frequently consumed, occurring in about 87 percent of the scats. Mule deer ( Odocoileus hemionus ) occurred in only 8 percent, and in 5 percent the native ungulate remains were not identifiable beyond order. This large percentage of big game in the diet is apparently unusual, because big game has been of minor importance in most coyote food-habit studies. The high incidence of leporids is consistent with other studies performed in arid intermountain areas. Although cricetines, especially deer mice ( Peromyscus maniculatus ), were trapped consistently in all habitats, months, and trapping areas, they were found in scats at a lower frequency than microtines and sciurids. This suggests a coyote hunting strategy that selected for the latter two groups.  相似文献   

18.
Soil compaction from human trampling, biking, and off-road motor vehicle traffic was quantitatively investigated in a blackbrush ( Coleogyne ramosissima ) shrubland in Kyle Canyon of the Spring Mountains in southern Nevada. A significant difference was detected in soil compaction, bulk density, and percent pore space at a particular frequency of visits in each of 4 disturbance types. On average a single vehicle pass was equivalent to 10 human footprints. Ten and 100 footprints were equivalent to 1 motorcycle pass and 10 vehicle passes, respectively. Soil compaction is a product of increased bulk density and decreased pore space. The degree of soil compaction is a function of disturbance type and visit frequency when examining these 2 factors independently. However, interactive effects of disturbance type and visit frequency on soil bulk density, compaction, and percent pore space were not significantly different. The greatest effects occurred during the first few passes, with changes per pass decreasing as the number of passes increased in all 4 trails. Results of this study suggest that the effects of hiking and biking slowly increase over time relative to the effects of motor vehicle traffic in the Coleogyne shrubland of Kyle Canyon in southern Nevada.  相似文献   

19.
Soil compaction from human trampling, biking, and off-road motor vehicle traffic was quantitatively investigated in a blackbrush ( Coleogyne ramosissima ) shrubland in Kyle Canyon of the Spring Mountains in southern Nevada. A significant difference was detected in soil compaction, bulk density, and percent pore space at a particular frequency of visits in each of 4 disturbance types. On average a single vehicle pass was equivalent to 10 human footprints. Ten and 100 footprints were equivalent to 1 motorcycle pass and 10 vehicle passes, respectively. Soil compaction is a product of increased bulk density and decreased pore space. The degree of soil compaction is a function of disturbance type and visit frequency when examining these 2 factors independently. However, interactive effects of disturbance type and visit frequency on soil bulk density, compaction, and percent pore space were not significantly different. The greatest effects occurred during the first few passes, with changes per pass decreasing as the number of passes increased in all 4 trails. Results of this study suggest that the effects of hiking and biking slowly increase over time relative to the effects of motor vehicle traffic in the Coleogyne shrubland of Kyle Canyon in southern Nevada.  相似文献   

20.
We investigated ecology of flannelmouth sucker ( Catostomus latipinnis ) from 1992 to 1997 in the 26-km Lee's Ferry reach of the Colorado River immediately below Glen Canyon Dam, Arizona. We captured by electrofishing a total of 212 fish and recaptured 52 previously tagged by others. Flannelmouth sucker were captured throughout the tailwater but tended to aggregate about 5 km of the dam, possibly reflecting blockage of historic migration routes. Catch per hour of electrofishing did not differ among years but was greater from November to February than other periods, suggesting seasonal movements of flannelmouth sucker into the tailwater: Mean lengths and weights of fish did not differ among years or seasons. Length frequency analyses also indicated there were no significantly yearly trends in proportion of catch within size classes of fish. Mean condition differed only among seasons and was greatest in February, lowest in August, coinciding respectively with pre- and post-spawning periods of flannelmouth sucker in tributary just down from Lee's Ferry. Recaptured fish migrated from initial tagging locations 1.4-23.1 km downstream from Lee's Ferry. Fifty-nine percent of recaptured fish with known initial tagging locations increased in length, and fish tagged initially as subadults or adults, respectively, grew an average of 45.9 mm and 5.5 mm per year.  相似文献   

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