Waterfowl distribution and abundance during spring migration in southern Oregon and northeastern California

We used aerial surveys to study abundance and distribution of waterfowl (ducks, geese, swans, and coots) during spring in southern Oregon and northeastern California (SONEC). Total waterfowl-use days in SONEC during the 119-day, 5 January–3 May, spring period was similar during 2002 (127,977,700) and 2003 (128,076,200) and averaged 1,075,900 birds per day (bpd); these estimates should be adjusted upward 4%–10% to account for areas not surveyed. Waterfowl abundance peaked in mid-March in both years: 2,095,700 in 2002 and 1,681,700 in 2003. Northern Pintail ( Anas acuta ) was the most abundant species in both years, accounting for 25.6% of the 2002 and 24.5% of the 2003 waterfowl-use days. Pintail abundance peaked during the 13 March survey at 689,300 in 2002 and 532,100 in 2003. All other dabbling ducks accounted for 27.6% and 28.6%, diving ducks for 13.5% and 9.2%, geese for 24.6% and 29.3%, swans for 2.8% and 1.9%, and coots for 5.8% and 6.4% of the spring waterfowl-use days in SONEC during 2002 and 2003, respectively. Although use days changed little for total waterfowl (+0.08%) and dabbling ducks (–0.1%), diving duck use was lower (–32%), and goose use days were greater (+19%) in 2003 than in 2002. Distribution was similar in both years, with the most waterfowl use in the Lower (66%) and Upper (14%) Klamath subregions; 2%–6% occurred in each of the other subregions. Although the Lower Klamath subregion received the greatest overall waterfowl use, distribution among subregions varied among species and surveys, and all subregions were important during some part of the spring for 1 or more species. Peak spring abundance in SONEC during 2002 and 2003 averaged 50.3% of the midwinter abundance in California (all survey regions) and southern Oregon (69-3 survey region) for all waterfowl, 46.1% for dabbling ducks, 62.4% for diving ducks, 68.8% for geese, 109.4% for swans, and 43.8% for coots. Each spring, 75% of all waterfowl use in SONEC occurred on federal, state, or Nature Conservancy lands (i.e., protected areas). On protected areas there was a higher percentage of dabbling ducks (80.5%), geese (70.5%), and coots (81.5%) than diving ducks (60.4%) and swans (49%). Waterfowl use of Klamath Basin National Wildlife Refuge (NWR) averaged 42% greater during spring 2002–2003 (568,500 bpd) than during 1998–2001 (Gilmer et al. 2004). Numerous factors likely impacted magnitude and distribution of waterfowl use of SONEC during spring, including weather, waterfowl populations, SONEC habitat, and species ecology. SONEC is a critical spring staging area for waterfowl that winter in the Central Valley of California and other Pacific Flyway regions and should be a major focus area for waterfowl-habitat conservation efforts.     

Nomenclatural changes and new species in Scolytidae (Coleoptera), Part III

New synonymy is proposed for Phlocosinus (Hylesinus) machilus (Schedl) (= Phlocosinus cinnamomi Tsai & Yin). New replacement names are proposed for junior homonyms as follows: Cyrtogenius africus for Cyrtogenius (Metahylastes) africanus (Eggers). Cyrtogenius elongatissimus for Cyrtogenius (Ozodendron) elongatus (Schedl), Cyrtogenius elongatulus for Cyrtogenius elongatulus for Cyrtogenius (Eidophelus) elongatus (Schedl), Cyrtogenius gracillimus for Cyrtogenius gracilis Browne, Cyrtogenius papuae for Cyrtogenius (Pelicerus) papuanus (Eggers), Cyrtogenius papuensis for Cyrtogenius (Eidophelus) papuanus (Shedl), Cyrtogenius ruginosus for Cyrtogenius (mimidendrulus) rugicollis (Browne). The following species are named as new to science: Indocryphalus machili (India), Olonthogaster jiri (India), Olonthogaster regalis (Sri Lanka), Phlocosinus phoebe (India), Scolytomimus andamanensis (Andaman Islands), Scolytomimus mimusopis (Sri Lanka), ( Scolytomimus quadridens (New Guinea), and Scolytomimus rectus (Sri Lanka).     

New synonymy and new species of American bark beetles (Coleoptera: Scolytidae)

New replacement names for junior homonyms are presented as follows; Acanthotomicus tuberculifer for A. (Mimips) tuberculatus Schedl 1967, Chactoptelius versicolor for C. (Acrantus) tricolor Schedl 1958, Hylesinopsis angolanus for H. (Aridiamerus) angolensis Schedl 1982, Hylurgops tuberculifer for H. tuberculatus Schedl 1947, Pseudothysanoes spinatifer for P. spinatus Wood 1956, Scolytodes aterrimus for S. ater (Hylocurosoma atrum Eggers) 1941, Scolytodes boliviensis for S. (Prionosceles) bolivianus Eggers 1928, Scolytodes brasiliensis for S. (Hexacolus) brasiliensis Schedl 1935, Scolytodes discriminatus for S. discedens Eggers 1943, Scolytodes elongatissimus for S. elongatus (Hylocurosoma elongatum Eggers) 1943, Scolytodes gennaens for S. genialis Wood 1978, Scolytodes laevigatulus for S. (Hexacolus) laevigatus Schedl 1962, Scolytodes laevicorpus for S. laevis (Hylocurosoma laeve Eggers) 1943, Scolytodes majus for S. major Eggers 1943, Scolytodes medialis for S. medius Eggers 1943. New synonymy is reported for Dactylipalpus niger Schedl (= D. unctus Wood), Dendroctonus armandi Tsai & Li (= D. prosorovi Kurenzov & Kononov), Sinophloeus porter Brèthes (= S. destructor Eggers). Species new to science include: Acacicis bicornis (New Guinea), Acacicis zeylanicus (Sri Lanka), Sphaerotrypes bengalensis (India), Sphaerotrypes costatus (North Andaman Island), Sphaerotrypes cristatus (Sri Lanka), Sphaerotrypes pentacme (Burma), Sphaerotrypes ranasinghei (Sri Lanka), Xylechinus ougeiniac (India), Xylechinus padus (India).     

Fleas (Siphonaptera: Ceratophyllidae, Ctenophthalmidae) from rodents in five southwestern states

Nine species of fleas were collected incidental to a survey of rodents for molecular studies in Arizona, Colorado, New Mexico, Texas, and Utah, south of latitude 38° N. Three species were parasites of woodrats, Neotoma spp.: Orchopeas neotomae Augustson was confirmed for Texas, and the distribution patterns of O. agilis (Rothschild) and O. schisintus (Jordan) were more clearly defined. Four species were parasites of mice, Peromyscus spp.: Aetheca wagneri (Baker) was a new flea for P. gratus Merriam, the distribution of O. leucopus (Baker) was extended to far west Texas, Plusaetis sibynus (Jordan) was new for Utah and N. lepida , and the range of Stenoponia americana (Baker) was extended west of the Continental Divide in New Mexico. Other species included Foxella ignota (Baker) and Meringis dipodomys Kohls.     

Leaf area ratios for selected rangeland plant species

Leaf area estimates are required by hydrologic erosion, and growth/yield simulation models and are important to the understanding of transpiration interception, CO 2 fixation, and the energy balance for native plant communities. Leaf biomass (g) to leaf area (mm 2 ) linear regression relationships were evaluated for 15 perennial grasses, 12 shrubs, and 1 tree. The slope coefficient (β 0 ) of the linear regression equation is a ratio of leaf area to leaf biomass and is defined as the leaf area ratio [LAR = one-sided leaf area (mm 2 )/oven-dry leaf weight (g)]. LAR represents β 0 in each regression equation, where Y = β 0 (X). Linear regression relationships for leaf area were computed ( r 2 = .84-.98) for all 28 native range species after full leaf extension. Within-plant estimates of leaf area for mesquite ( Prosopis glandulosae Torr. var. glandulosae [Torr.] Cockll.) or lime prickly ash ( Zanthoxylum fagara [L.] Sarg.) were not significantly different ( P ≤ .05). LARs for three of the shrubs and the tree were established at four different phenological stages. There were no significant differences ( P ≤ .05) in LARs for lime prickly ash, mesquite, and Texas persimmon ( Diospyros texana Scheele) after full leaf extension during the growing season. The LAR relationship for Texas persimmon changed significantly after full leaf extension. LAR relationships for Texas colubrina ( Colubrina texensis [T. & G.] Gray) changed in response to water stress.     

Home-range size and overlap of sympatric male mule and white-tailed deer in Texas

Information about the ecology of sympatric male deer is limited, which may influence management strategies for these species. We estimated home-range and core-area sizes and overlap, and survival of sympatric male desert mule deer ( Odocoileus hemionus eremicus ) and white-tailed deer ( Odocoileus virginianus ) in west central Texas. We captured 18 males of each species, fitted them with radio-collars, and monitored them for mortality from 2000 through 2003. We calculated home ranges for 7 males of each species in 2001 and 2002. Home-range sizes of mule deer (8.8 km 2 ) and white-tailed deer (7.4 km 2 ) were similar. Interspecific home-range overlap was less common than intraspecific overlap. Mean annual survival was 0.76 (SE = 0.04) for mule deer and 0.80 (SE = 0.06) for white-tailed deer. The high degree of home-range overlap and similar survival between the 2 deer species suggest that management targeting only 1 species may be unfeasible.     

Nomenclatural changes and new species of Scolytidae (Coleoptera)

New replacement names for junior homonyms are presented as follows; Acanthotomicus tuberculifer for A. (Mimips) tuberculatus Schedl 1967, Chactoptelius versicolor for C. (Acrantus) tricolor Schedl 1958, Hylesinopsis angolanus for H. (Aridiamerus) angolensis Schedl 1982, Hylurgops tuberculifer for H. tuberculatus Schedl 1947, Pseudothysanoes spinatifer for P. spinatus Wood 1956, Scolytodes aterrimus for S. ater (Hylocurosoma atrum Eggers) 1941, Scolytodes boliviensis for S. (Prionosceles) bolivianus Eggers 1928, Scolytodes brasiliensis for S. (Hexacolus) brasiliensis Schedl 1935, Scolytodes discriminatus for S. discedens Eggers 1943, Scolytodes elongatissimus for S. elongatus (Hylocurosoma elongatum Eggers) 1943, Scolytodes gennaens for S. genialis Wood 1978, Scolytodes laevigatulus for S. (Hexacolus) laevigatus Schedl 1962, Scolytodes laevicorpus for S. laevis (Hylocurosoma laeve Eggers) 1943, Scolytodes majus for S. major Eggers 1943, Scolytodes medialis for S. medius Eggers 1943. New synonymy is reported for Dactylipalpus niger Schedl (= D. unctus Wood), Dendroctonus armandi Tsai & Li (= D. prosorovi Kurenzov & Kononov), Sinophloeus porter Brèthes (= S. destructor Eggers). Species new to science include: Acacicis bicornis (New Guinea), Acacicis zeylanicus (Sri Lanka), Sphaerotrypes bengalensis (India), Sphaerotrypes costatus (North Andaman Island), Sphaerotrypes cristatus (Sri Lanka), Sphaerotrypes pentacme (Burma), Sphaerotrypes ranasinghei (Sri Lanka), Xylechinus ougeiniac (India), Xylechinus padus (India).     

Nomenclatural changes and new species in Platypodidae and Scolyidae (Coleoptera), Part II

In Platypodidae the new name Genyocerus strohmeyeri replaced the junior homonym G. albipennis Strohmeyer, 1942, and the new name Platypus applanatulus replaced the junior homonym Platypus applanatus Schedl, 1976. New names are presented in Scolytidae as replacements for junior homonyms as follows: Cryphalus brownei for Cryphalus artocarpus Schedl, 1958; Cyclorhipidion dihingicum for Xyleborus dihingensis Schedl, 1951; Hypothenemus aterrimulus for Lepiceroides (now Hypothenemus ) aterrimus Schedl, 1957; Hypothenemus krivolutskayae for Hypothenemus insularis Krivolutskaya; Pityophthorus africanulus for Neodryocoetes (now Pityophthorus ) africanus Schedl, 1962; Scolytogenes papuensis for Xylocryptus (now Scolytogenes ) papuanus Schedl, 1975; Scolytogenes paradoxus for Scolytogenes papuanus Schedl, 1979; Xyleborinus spiniposticus for Eidophelus (now Xyleborinus ) spinipennis Schedl, 1979; Xyleborus formosae for Xyleborus formosanus Browne, 1981. New combinations for fossil Scolytidae include Dryocoetes diluvialis for Pityophthoroidea diluvialis Wickham, 1916, and Hylesinus hydropicus for Apidocephalus hydropicus Wickham, 1916. Phloeotribus zimmermanni Wickham, 1916, is transferred to the family Curculionidae. In Scolytidae, Cryphalophilus Schedl, 1970, is a junior generic synonym of Scolytogenes Eichhoff; Macrocryphalus Nobuchi, 1981, is a junior generic synonym of Hypothenemus Westwood, 1836; Nipponopolygraphus Nobuchi, 1981, is a junior generic synonym of Polygraphus Erichson, 1836; Pseudocosmoderes Nobuchi, 1981, is a junior generic synonym of Cosmoderes Eichhoff, 1878; Taphrocoetes Pfeffer, 1987, is a junior generic synonym of Taphrorychus Eichhoff; Trypanophellos Bright, 1982, is a junior generic synonym of Liparthrum Wollaston. New specific synonymy in Scolytidae includes: Brachyspartus moritzi Ferrari (= Corthylus obtusus Schedl), Carphoborus minimus (Fabricius) (= Carphobhorus balgensis Murayama), Coccotrypes dactyliperda (Fabricius) (= Coccotrypes tropicus Eichhoff), Cryphalus scabricollis Eichhoff (= Cryphalus brevicollis Schedl), Ficicis despects (Walker) (= Hylesinus samoanus Schedl), Hylastes plumbeus Blandford (= Hylurgops fushunensis Murayama), Hylurgops interstitialis (Chapuis) (= Hylurgops niponicus Murayama), Hylurgops spessivtsevi Eggers (= Hylurgops modestus Murayama), Ips stebbingi Strohmeyer (= Ips schmutzenhoferi Holzschuh), Phloeosinus rudis Blandford (= Phloeosinus shotoensis Murayama, Polygraphus kaimochi (Nobuchi) (= Polygraphus querci Wood), Polygraphus proximus Blandford (= Polygraphus magnus Murayama), Scolytogenes braderi Browne (= Scolytogenes orientalis Schedl), Scolytoplatypus parvus Sampson (= Scolytoplatypus ruficauda Eggers), Sphaerotrypes querci Stebbing (= Chramesus globulus Stebbing, Sphaerotrypes tectus Beeson), Sueus niisimai (Eggers) (= Sphaerotrypes controversae Murayama), Tomicus brevipilosus (Eggers) (= Blastophagus khasianus Murayama, Blastophagus multisetosus Murayama). The European Hylastes opacus Erichson is reported as an established breeding population in New York (USA). Phloeosinus armatus Reitter of Asia Minor is reported as causing economic damage as a new introduction to Los Angeles County, California. The following species are named as new to science: Cyclorhipidion subagnatum (Philippine Islands), Dendrotrupes zealandicus (New Zealand), Polygraphus thitsi (Burma), Triotemnus pilicornis (India), and Xyleborus mangificus (Peru).     

Brood parasitism and nest survival of Brown-headed Cowbird hosts at high-elevation riparian sites in the eastern Sierra Nevada, California

Deciduous riparian ecosystems in the western United States provide habitat for a higher density of breeding birds than reported for any other avian habitat type and provide habitat for more breeding bird species than adjacent uplands. On the east slope of the Sierra Nevada, riparian ecosystems make up Molothrus ater )—an obligate brood parasite that forages on bare ground and feedlots but typically commutes to distinct shrubland or woodland habitats for breeding. We examined nest survival, brood parasitism, breeding phenology, and causes of nest failure for birds at North Lake and Rock Creek: 2 high-elevation (>2500 m) riparian breeding habitats adjacent to recreational development and within cowbird commuting distance to additional potential foraging sites. Nest survival tended to be higher for host species at Rock Creek than for those at North Lake, but parasitism rates were not significantly different between plots. Of 21 open-cup nesting species, 12 were parasitized. We found the highest rate of parasitism (92%) for Warbling Vireos ( Vireo gilvus ) at North Lake, and parasitism contributed to lower total nest survival there (14%). For nearly all species, parasitized nests were less successful and produced fewer young than nonparasitized nests. However, predation was the leading cause of complete nest failure across all species and contributed to the lowest total nest survival estimates for Western Wood-Pewees ( Contopus sordidulus, 11%) and Dusky Flycatchers ( Empidonax oberholseri, 15%) at North Lake and for Dark-eyed Juncos ( Junco hyemalis, 15%) at Rock Creek. Nest survival was relatively high for Western Wood-Pewees (41%) at Rock Creek and for Yellow Warblers ( Dendroica petechia, 47%) at North Lake. We noted whether the arrival of pack animals at pack-station corrals contributed to variation in cowbird numbers at corrals or in parasitism rates at the 2 sites. Cowbirds occupied corrals before and after pack-stock arrival, and most host clutches were completed prior to pack-stock arrival at nearby corrals, suggesting that the presence of pack animals did not directly affect cowbird host species.     

Nesting and brood-rearing characteristics of Chukars in west central Idaho

We analyzed attributes from 23 nests (10 renests) and 46 brood locations of radio-marked Chukars ( Alectoris chukar ) in the lower Salmon River canyon of west central Idaho in 1995 and 1996. Nesting effort was 100%, apparent nest success was 45%, and estimated time from destruction or abandonment of a nest to initiation of laying a subsequent nest averaged 13 ± 5 days s x . Average clutch size for 1st nests (14.5 ± 1.0) was greater ( P = 0.017) than renests (10.4 ± 1.1). Cover types used by nesting Chukars included grass/forb (48% of nests), rock (43%), and shrub (9%), whereas the most common structure used for nests was rock outcrop (57%). Chukars did not use yellow starthistle ( Centaurea solstitialis ) habitats differently from what was expected ( P = 0.08) for nesting, but birds with broods selected areas with less starthistle ( P < 0.001). Chukar broods, which averaged 12.0 ± 1.1 chicks, used shrub and grass/forb cover types approximately equally (43% and 47% of locations, respectively) but rock habitats infrequently (11%).     

Survival rates of translocated and native Mountain Quail in Oregon

We estimated survival rates for 232 radio-tagged native ( n = 157) and translocated ( n = 75) Mountain Quail ( Oreortyx pictus ) from 1997 to 1999 in Hells Canyon National Recreation Area (HCNRA) in northeastern Oregon and in the Cascade Mountain Range (CMR) of southwestern Oregon. For the combined areas the estimated survival rate during 150-day intervals was 0.42 ± 0.04. Estimated survival was 0.41 ± 0.04 for Mountain Quail in HCNRA and 0.34 ± 0.34 for quail in CMR. There were no differences in survival functions for native quail in HCNRA and CMR ( P = 0.91), for translocated and native quail in HCNRA ( P = 0.93), for native quail in CMR and translocated quail in HCNRA ( P = 0.97), or for birds released in the fall and birds released in the winter ( P = 0.57). Male and female survival functions were significantly different ( X 2 1 = 4.61, P = 0.02). The estimated risk ratio for males was 0.66 that of females. Translocated wild Mountain Quail appeared to have survival rates similar to native quail. Mountain Quail experienced mortalities of > 50% over a 150-day interval in both the conifer forests of the western Cascade Mountain Range and the semiarid habitats of northeastern Oregon. With the ability to rapidly expand their populations and exploit marginal habitats, Mountain Quail are excellent candidates for reintroduction programs, and translocated wild Mountain Quail could be used to supplement declining populations.     

Monitoring Idaho fescue grasslands in the Big Horn Mountains, Wyoming, with a modified Robel pole

The reliability of monitoring visual obstruction and estimating standing herbage with a modified Robel pole was examined for high-elevation meadows in sedimentary soils on the Bighorn National Forest, Wyoming. Our objectives were to (1) test a modified pole graduated with 1.27-cm (0.5-inch) bands for estimating standing herbage based on linear regression of visual obstruction readings (VORs) on standing herbage, (2) validate the derived regression, (3) provide sample size estimates, and (4) develop guidelines for monitoring mountain grasslands. Each transect had 20 visual obstruction stations spaced 10 meters apart with 4 visual obstruction readings at each station. At 4 stations, vegetation within a 0.25-m 2 area was clipped at ground level. VORs and clipped standing herbage were averaged by transect for analysis. Visual obstruction reliably predicted average standing herbage (dry weights) for mountain meadows ( r 2 = 0.81, s x&macr; = 382 kg &sdot; ha &ndash;1 ). Standing herbage ranged from 387 kg &sdot; ha &ndash;1 to 3930 kg &sdot; ha &ndash;1 , with a mean of 1742 kg &sdot; ha &ndash;1 . A validation data set of 13 transects sampled across the range of variation in standing crop showed that 85% of transects fell within the 90% prediction limits. We recommend a minimum of 4 transects for monitoring key areas or small areas up to 259 ha (640 acres) when managers need to consider differences in VOR bands and address multiple objectives. Cluster analyses (ISODATA) applied to the pole readings resulted in 4 visual obstruction categories: short, short-intermediate, tall-intermediate, and tall. This tool provides a simple, reliable, and cost-effective (time-saving) alternative to clipping vegetation and obtaining dry weights for monitoring. Mention of a proprietary product does not constitute a guarantee or warranty of the product by USDA or the authors and does not imply its approval to the exclusion of other products that also may be suitable.     

Noteworthy flea records from Utah, Nevada, and Oregon

Collections from several scattered western localities have (1) extended the ranges in Nevada of two sagebrush vole fleas, Oropsylla bacchi johnsoni and Megabothris clantoni prince , (2) provided a second record for Utah of the rarely collected flea, Delotelis telegoni , and (3) included additional examples of unusual and seldom reported host-flea relationships for the area.     

Isozymes of an autopolyploid shrub, Atriplex canescens (Chenopodiaceae)

Diploid, tetraploid, and hexaploid populations of Atriplex canescens ( x =9) were examined for 18 isozyme systems. Of 24 interpretable loci, only one locus (Per 1 ) was polymorphic. Another locus (Per 2 ) showed a dosage effect. Genetic distance values, D, ranged from near 0 to 0.05, which are in the normal range for local species races. Results from clonal ramets gave identical results. The data and analyses support an essentially autopolyploid origin for the polyploid populations examined.     

Diameter-weight relationships for juniper from wet and dry sites

Height-diameter (basal or canopy) relationships for Juniperus scopulorum trees taken from wet and dry sites were quite different, but total aboveground weight - diameter relationships for trees taken from the two sites did not differ. It is shown that log total weight (kg) = approximately 1.7 + 2.26 log basal diameter (cm) = - 2.55 + 2.98 log canopy diameter (cm). Though the first relationship (r 2 = 0.98) is stronger than the second (r 2 = 0.80), the canopy diameter-weight relationship may be useful for estimating tree weights from aerial photos. Root - shoot ratios for wet site trees 5, 12, and 31 cm in basal diameter were 37, 27, and 26 percent, respectively.     

Diet of the Mogollon vole as indicated by stable-isotope analysis (δ 13 C and δ 15 N)

There are no published studies on the diet of Mogollon voles ( Microtus mogollonensis ) although this species occurs throughout the Southwest in montane forestlands. Mogollon voles are believed to be herbivorous, selecting the vegetative portion of grass as their dominant food source. Herbivores frequently select more easily digested C 3 plants over C 4 plants; we thus expected Mogollon voles would feed primarily on C 3 plants. We collected hair samples from Mogollon voles captured in northern Arizona between 1967 and 2003 and plant samples from some capture sites. Then we compared stable carbon (δ 13 C) and nitrogen (δ 15 N) isotope ratios to investigate dietary preferences for C 3 or C 4 plants. Mean isotope ratios for C 3 plants we sampled were –26.84‰ ( s = 0.17) for δ 13 C and –0.02‰ ( s = 0.32) for δ 15 N. For C 4 plants, mean isotope ratios for δ 13 C and δ 15 N were –15.04 ‰ ( s = 0.38) and –0.74‰ ( s = 0.55), respectively. Mogollon voles were largely herbivorous based on δ 15 N (mean and standard error: 3.77 &#177; 0.17‰) and used C 3 plants more than C 4 based on δ 13 C (–24.21 &#177; 0.14‰). Activities that lead to changes in plant species composition or reduction in C 3 plants in montane grasslands and forests (e.g., excessive ungulate grazing) may reduce habitat quality for Mogollon voles.     

Habitat and spatial relationships of nesting Swainson's Hawks ( Buteo swainsoni ) and Red-tailed Hawks ( B. jamaicensis ) in northern Utah

A total of 28 Swainson's Hawk ( Buteo swainsoni ) and 30 Red-tailed Hawk ( B. jamaicensis ) nests were found in Cache Valley, Utah, during the summers of 1992 and 1993. All nests were in trees, but only Red-tailed Hawks nested in dead trees (30%). In the intensive study area, nesting densities were 0.10 nests/km 2 for Swainson's Hawk and 0.08 nests/km 2 for Red-tailed Hawk. Nearest-neighbor nest distances were significantly shorter among Swainson's Hawks (1.74 km) than among Red-tailed Hawks (2.83 km). Congeneric nearest-neighbor distances were significantly shorter than conspecific distances for Red-tailed Hawks (1.59 vs 2.83 km) but not for Swainson's Hawks (1.52 vs. 1.74). GIS analysis of habitat types was made for 2-km radii around nest sites. Cropland was the dominant land cover type at nest sites of both species and no significant difference was found between species. Swainson's Hawk nest sites contained significantly more pasture, whereas Red-tailed Hawk nest sites contained significantly more juniper, maple, and sagebrush. Only Red-tailed Hawk nests ( n = 8; 27%) were found on the periphery of the valley at the base of foothills of the Cache Mountains. This preference resulted in a significantly higher elevation for Red-tailed Hawk nest sites. Swainson's Hawk nests occurred only on the valley floor on level terrain. Distance to the nearest paved road and building was very similar for both species, implying that little difference exists in tolerance levels for human activities. Overall, multivariate niche overlap for habitat was high (0.89), indicating a lack of habitat partitioning between these 2 Buteos in Cache Valley.     

Partitioning phenotypic variation: genotypic,environmental and residual components from bryozoan skeletal morphology

Using morphometric studies of colonial (clonal) organisms such as Bryozoa grown as replicates in controlled laboratory experiments, phenotypic variation (hard part morphology) can be partitioned into its genotypic and environmental (ecophenotypic) components. The interaction between these, i.e. different genotypic responses to the same environmental change, can also be recognized. Palaeobiological studies are inherently constrained by species concepts based on morphotypes (preserved morphological phenotype). Uncertainties associated with fossil species concepts restrict the deductive resolution potential of fossil taxa in discussions of the broader biological questions of species evolution, ecology, biogeography and phylogeny. The relationship between species-level morphological variation and genetic variation in modern taxa is central to evaluating the viability of fossil morphotypes as biological species. Results from a preliminary study of three genotypes of Electra pilosa L., grown as replicate colonies in tanks comprising different microenvironmental conditions, allow for direct evaluation of morphospecies concepts. Numerical analyses (Cluster Analysis, Principal Component Analysis and Two-way ANOVA) of six morphometric characters demonstrated a strong Genotype control over zooid morphology and limited environmental (Tank) effects with minimal environmental differences among tanks. No significant Genotype by Tank (=environment) interactions were found for any characters. These results demonstrate that it is possible to quantify the extent to which a given trait is plastically expressed in different environments. The strong degree of correlation between morphology and genetics for this species is encouraging for the use of morphotypes as proxies for biological species.