Formation and contents of yellow-pine chipmunk ( Tamias amoenus ) winter larders

Despite much attention to the foraging habits and hibernation patterns of food-storing mammals, little is known about the contents of winter larders under natural conditions or how animals prepare a winter larder. Here we describe the contents of 15 yellow-pine chipmunk ( Tamias amoenus ) winter larders from 3 different years and describe the movement of scatter-hoarded seeds into larders. We found larders by locating 14 radio-collared chipmunks in their winter dens. One additional larder was found by tracking the movement of seeds labeled with radioactive scandium-46 from scattered caches into the larder. Chipmunks formed winter dens and rapidly provisioned winter larders in the fall, just before the onset of winter. Surface caches were dynamic, with seeds residing in 1–6 cache sites (mean = 2.6, SD = 1.1) before being found in the larder. Distances from scattered caches to the winter larder were 34.5 m (SD = 17.1). Contents of winter larders consisted of pine and shrub seeds. In 14 of the 15 larders, pine seeds contributed most to the size and caloric content of larders. Pine seeds and other seeds found in winter larders were produced by plants 2–4 months before the onset of winter. We conclude that if yellow-pine chipmunks did not scatter-hoard seeds during summer and autumn, seeds would not have been available for use in winter larders.     

Black bears ( Ursus americanus ) harvest Jeffrey pine ( Pinus jeffreyi ) seeds from tree canopies

Despite much attention to the foraging habits and hibernation patterns of food-storing mammals, little is known about the contents of winter larders under natural conditions or how animals prepare a winter larder. Here we describe the contents of 15 yellow-pine chipmunk ( Tamias amoenus ) winter larders from 3 different years and describe the movement of scatter-hoarded seeds into larders. We found larders by locating 14 radio-collared chipmunks in their winter dens. One additional larder was found by tracking the movement of seeds labeled with radioactive scandium-46 from scattered caches into the larder. Chipmunks formed winter dens and rapidly provisioned winter larders in the fall, just before the onset of winter. Surface caches were dynamic, with seeds residing in 1–6 cache sites (mean = 2.6, SD = 1.1) before being found in the larder. Distances from scattered caches to the winter larder were 34.5 m (SD = 17.1). Contents of winter larders consisted of pine and shrub seeds. In 14 of the 15 larders, pine seeds contributed most to the size and caloric content of larders. Pine seeds and other seeds found in winter larders were produced by plants 2–4 months before the onset of winter. We conclude that if yellow-pine chipmunks did not scatter-hoard seeds during summer and autumn, seeds would not have been available for use in winter larders.     

Scatter-hoarding behavior of deer mice ( Peromyscus maniculatus )

Deer mice ( Peromyscus maniculatus ) are known to larder hoard food, but their scatter-hoarding behavior is poorly documented. Eleven deer mice were each presented with 150 Jeffrey pine ( Pinus jeffreyi ) seeds in 10 γ 10- m enclosures in Jeffrey pine forests on the east slope of the Sierra Nevada. Subjects made a mean ± 1 s of 31.2 ± 30.0 caches per trial. Caches were shallow (most 2-12 mm deep) and usually contained only 1 or 2 seeds. Most caches were made at the edge of antelope bitterbrush ( Purshia tridentata ) shrubs in mineral soil or in thin layers of plant litter. These results suggest that deer mice might make a significant contribution to the dispersal of Jeffrey pine.     

Diets of sympatric bobcats and coyotes during years of varying rainfall in central Arizona

We collected fecal samples (scats) of sympatric bobcats ( Lynx rufus ) and coyotes ( Canis latrans ) between 2000 and 2003 in a 53,600-ha area of the Upper Sonoran Desert in central Arizona. Our objective was to investigate composition, diversity, and overlap of diets of bobcats and coyotes in relation to varying rainfall in the Sonoran Desert of central Arizona. In general, bobcats ate more rodents than did coyotes, and coyotes ate more lagomorphs, large prey, and fruit/seeds than did bobcats. Composition of bobcat diets was independent of differences among years in annual rainfall and seasonal rainfall during summer–autumn (May–October) and winter–spring (November–April). Composition of coyote diets also was independent of drought conditions among years during summer–autumn, but coyotes ate more large prey and fewer rodents during years with winter–spring drought. Seasonally, bobcats ate more rodents than did coyotes in summer–autumn and winter–spring, whereas coyotes ate more lagomorphs than did bobcats during winter– spring, and more large prey and fruit/seeds in both seasons. Coyotes ate more large prey and lagomorphs during winter–spring, when seasonal rainfall was higher, and more fruit/seeds in summer–autumn, when seasonal rainfall was lower. Diversity of diets was consistently higher for coyotes than for bobcats, and increased for bobcats but not for coyotes during winter–spring drought and during higher seasonal rainfall in winter–spring. Overlap of diets between predators was independent of rainfall levels. We suggest that bobcats in the Sonoran Desert are more selective, specialized predators and that coyotes are more generalist, opportunistic predators. We hypothesize that, although diversity of bobcat food items and composition of coyote diets differ with varying rainfall in the Sonoran Desert, patterns of feeding strategy are independent of seasonal differences in precipitation and effects of drought, and bobcats and coyotes partition food resources independently of varying rainfall.     

Yellow pine chipmunks cannot climb quaking aspens: implications for avian nest site selection

Predation of eggs or nestlings is generally believed to be the most influential factor limiting passerine reproductive success. Thus, there should be strong selective pressures for birds to place their nests in sites that are inaccessible to predators or that are less likely to be discovered by them. We found and monitored 231 nests of 4 species of arboreal, cup-nesting birds: Western Wood-Pewee ( Contopus sordidulus ), Warbling Vireo ( Vireo gilvus ), American Robin ( Turdus migratorius ), and Yellow-rumped Warbler ( Dendroica coronata ). We determined strength of nest tree species selection by comparing nest trees and tree species availability. Western Wood-Pewees and Warbling Vireos demonstrated strong preference for placing nests in quaking aspen ( Populus tremuloides ). Yellow-rumped Warblers showed a weak preference for aspen, and American Robins demonstrated no preference. We designed a series of experiments to determine whether yellow pine chipmunks ( Tamias amoenus ), an abundant nest predator, could climb aspen trees and, if so, what factors might prevent them from doing so. Yellow pine chipmunks were unable to climb aspen but showed no difficulty in climbing and maneuvering on lodgepole pine ( Pinus contorta ) boles, which were identical in diameter to aspen boles. Refuge from chipmunks as potential nest predators is likely contributing to nest site selection for a few arboreal cup-nesting bird species where aspen trees are available.     

Summer burrows of Ord's kangaroo rats ( Dipodomys ordii ) in western Nebraska: food content and structure

Extent of larder hoarding differs among species of kangaroo rats, and limited information is available for food stored in burrows by Ord’s kangaroo rat ( Dipodomys ordii )—the most widespread species of Dipodomys. I excavated 9 burrows recently used by adult D. ordii during summer in the Sandhill Region of Nebraska. I observed only small quantities of food stored in burrows. Eight of 9 burrows contained segments of sand dropseed ( Sporobolus cryptandrus ) in limited quantities. These segments consisted of upper leaves with fruits (containing seeds) housed in sheaths. My observations represent the first documentation of D. ordii storing food in burrows under natural conditions. Compared to the burrows of other species of kangaroo rat, burrows of D. ordii were simple in structure with 1 main tunnel and 1–3 entrances. In summer, Ord’s kangaroo rats commonly harvest seeds from plants in the Sandhill Region of Nebraska, but individuals apparently do not store large quantities of food in burrows, which suggests they store food in scatter hoards during this season.     

Seasonal changes of pelage in the roe deer Capreolus capreolus and its role in thermoregulation

Summary

Seasonal changes of coat in the roe buck (Capreolus capreolus) have been studied in field animals throughout the year. Spring and autumn moults produce summer and winter coats geared to the seasons. The winter guard hairs are much wider than summer guard hairs because the medullary spaces are larger. This results in a close packing of the winter hairs and the air contained within them acts as an efficient insulator.     

Plague in pine martens and the fleas associated with its occurrence

Thirteen pine martens ( Martes Americana ) were sampled periodically from July 1979 to September 1980 for plague ( Yersinia pestis ) antibodies and their fleas collected and identified. Four individuals were positive for plague antibodies on 8 of 24 sampling occasions. Titer peaks in these individuals occurred simultaneously in early winter but fell to undetectable levels by late spring. A chipmunk flea ( Monopsyllus ciliatus ) was the most common ectoparasite constituting 55% of all individuals collected. Thirty-one percent of all fleas belonged to Chaetopsylla floridensis, a species previously unreported in California. The remains of ground-dwelling sciurids (chipmunks, Eutamias spp., and ground squirrels, Spermophilus spp.) were very common in marten scats during the period preceding elevated titers. For this reason, and the fact that 92% of all fleas collected from martens during this same period were found more commonly on chipmunks and ground squirrels, these rodents were implicated as the source of the martens’ exposure to plague.     

Winter habitat selection patterns of Merriam's turkeys in the southern Black Hills, South Dakota

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.     

Gray Partridge foraging ecology in eastern South Dakota

We examined crop contents of 217 Gray Partridge ( Perdix perdix ) collected during a two-year period in eastern South Dakota. Row crop grains (corn, sunflowers) dominated late fall, winter, and spring diets. Small grains (oats, barley, wheat, rye) were rarely consumed although fields of small grains were widely available. During a severe winter when waste row crop grains were buried by snow, partridge consumed more leafy vegetation. Insects dominated the early summer diet, while foxtail ( Setaria spp.) seeds were a major late summer and early fall food.     

Feeding ecology of Gila boraxobius (Osteichthyes: Cyprinidae) endemic to a thermal lake in southeastern Oregon

Gila boraxobius is a dwarf species of cyprinid endemic to a thermal lake in southeastern Oregon. Despite a relatively depauperate fauna and flora in the lake, 24 food items were found in intestines of G. boraxobius. Ten of the 24 foods, including six insects, were of terrestrial origin. The relative importance of food items fluctuated seasonally. Diatoms, chironomid larvae, microcrustaceans, and dipteran adults were the primary foods during spring. In summer, diatoms decreased and terrestrial insects increased in importance. During autumn important foods were terrestrial insects, chironomid larvae, and diatoms. Diatoms and microcrustaceans increased in importance during winter. Chironomid larvae were of importance in winter, when the importance of terrestrial food items decreased substantially. Similar food habits were observed between juveniles and adults, except that adults consumed more gastropods and diatoms and juveniles consumed more copepods and terrestrial insects. Gila boraxobius feeds opportunistically with individuals commonly containing mostly one food item. Fish typically feed by picking foods from soft bottom sediments or from rocks. However, fish will feed throughout the water column or on the surface if food is abundant there. Gila boraxobius feeds throughout the day, with a peak in feeding activity just after sunset. A daily ration of 11.1 percent body weight was calculated for the species during June. A comparison of food habits among G. boraxobius and populations of G. alvordensis during the summer shows that all are opportunistic in feeding, but that G. boraxobius relies more heavily on terrestrial foods.     

Bristlecone pine and Clark's Nutcracker: probable interaction in the White Mountains, California

Many bristlecone pines in the White Mountains, California, are members of multistem clumps. We propose that these clumps have arisen by multiple germinations from seed caches of Clark’s Nutcracker, as occurs in several other pine species. The commonness of nutcrackers and their caching of singleleaf pinyon seeds in the study area provide supporting evidence. Other vertebrates appear unlikely to be responsible for the stem clumps. Seed burial may be required to establish regeneration on these adverse sites where bristlecone pine attains great longevity.        

Spring and winter records of the eastern pipistrelle ( Perimyotis subflavus ) in southeastern New Mexico

Eastern pipistrelles ( Perimyotis subflavus ) were first documented from South Dakota, western Texas, and New Mexico during recent years, suggesting that the distribution of this species is expanding westward across central parts of North America. In New Mexico, only 2 records of P. subflavus previously were known—one from summer and one from autumn. Here we report on 3 new records of P. subflavus from southeastern New Mexico, including the first 2 records from winter and the first record from spring. One individual in winter was observed hibernating in a cave in Chaves County. Our records and previous ones from autumn and summer suggest that this species is resident throughout the year in New Mexico.     

Larval development of the coronuloid barnacles Austrobalanus imperator (Darwin), Tetraclitella purpurascens (Wood) and Tesseropora rosea (Krauss) (Cirripedia,Tetraclitidae)

The presence of embryos in the mantle cavity of A. imperator, T. purpurascens and T. rosea was monitored over two years. Tesseropora rosea showed a clearly defined breeding season in summer and early autumn. Seasonal breeding in A. imperator and T. purpurascens was less well defined, a small number of gravid individuals being present during most of the year. Breeding increased during the late autumn and early winter in A. imperator and during winter, spring and early summer in T. purpurascens. The larval stages of A. imperator, T. purpurascens and T. rosea are described from larvae reared in the laboratory. Separation of the larval stages between these species depends on fine morphological detail. Distinctive larval features permit the separation of coronuloid larvae from those of the other balanomorph superfamilies, but coronuloid nauplii resemble balanoid nauplii more than chthamaloid nauplii.     

Seasonal abundance and life cycle of Archaeomysis articulata (Crustacea: Mysidacea) on a sandy beach of western Hokkaido,Japan

Abundance and life cycle of the sandy beach mysid Archaeomysis articulata Hanamura were investigated based on seasonal collections over 2 years in the surf-swept intertidal zone of an open sandy beach in Ishikari Bay, western Hokkaido, Japan. The number of mysids in the intertidal zone increased from winter to spring, reaching its maximum in summer to autumn (average >2500 ind. m^-2), and decreased considerably towards the end of the year. The abundance was maintained at a minimal level (<200 ind. m^-2) throughout the winter. The breeding season was March to November, during which the liberation of young was most intensive from late April to mid-October. Three alternate generations, including overwintering, spring and summer generations, were suggested from field observations. Archaeomysis articulata is primarily iteroparous; only a restricted number of breeding females could produce more than two broods. The life span was estimated to be 7–9 months for the overwintering generation and 2.5–3.5 months for the spring–summer generations. The sex ratio fluctuated at samplings, with a tendency toward female dominance (overall mean=54%). The number of embryos carried by a single female ranged from 16 to 94, tending to increase with increasing size of females. The size of egg-like embryos varied seasonally from 0.45 to 0.54mm, being largest in spring and smallest in summer, with no correlation to the length of females; water temperature is considered an important factor in regulating the size of eggs. The embryonic development time was estimated to be 1.5 months for the spring generation (water temperature 5–10°C), and much shorter than this for the summer and overwintering generations. The mortality rate during embryonic development was estimated to be 7–18%.     

Seasonal trends and colonization patterns of macroinvertebrate assemblages in two streams with contrasting flow regimes

Patterns of colonization by macroinvertebrates were examined in two streams that differ in flow regime: a snowmelt system and a mesic groundwater system. Experiments were conducted during spring runoff, summer baseflow, and winter baseflow using artificial substrata. Colonization patterns reflected seasonal changes in benthic macroinvertebrate assemblages and life histories in each stream. The density and biomass of benthic organisms were approximately 3X greater in winter than in either spring or summer for both streams. Similarly, colonization was greater in winter than in spring or summer for both streams. In spring, colonization patterns were different between streams, with colonization being imperceptible in the snowmelt stream. Macroinvertebrate abundance fluctuated during the summer colonization experiment at both sites, resulting from a complex interplay among population emergence, recruitment, and/or movement. Assemblages in the snowmelt system primarily comprised mobile or ruderal taxa, such as Beatis tricaudatus and Chironomidae, whereas relatively sessile taxa, such as Glossoma nigrior , were predominant in the mesic groundwater system. Seasonal patterns of colonization differed among stream types primarily because of the profound interplay of flow regime and temperature on benthic community structure and organism life history.     

Composition and abundance of periphyton and aquatic insects in Sierra Nevada, California, stream

The species composition of periphyton and benthic insect communities and abundances of common taxa (&;gt;0.1&;#37; of individuals) were examined during snow-free months in Convict Creek, a permanent snowmelt- and spring-fed stream in the Sierra Nevada of California. The communities were highly diverse. The most abundant taxa in the periphyton were diatoms ( Achnanthes minutissima, Cocconeis placentula lineata, Cymbella microcephala, C. sinuata, Fragilaria construens, F. crotonensis , Navicula spp., Synedra acus , and S. rumpens ), except in late spring and summer when several seasonal blue-green algae ( Chamaesiphon incrustans, Lyngbya spp. and Oscillatoria spp.) are at their maximum densities. Most common periphyton taxa vary systematically in abundance with season, but relative abundances of taxa also appear to be influenced by streambed scouring and by concentrations of ambient nutrients. Data on population densities and length frequencies of larval and nymphal stages of common benthic insects and occurrences of pupal and adult stages were examined to determine life history patterns. Taxa hatching in winter and spring and abundant as immatures in late spring include ephemeropterans ( Epeorus longimanus, Drunella flavilinea , and Caudatella heterocaudata ), plecopterans ( Calineuria californica, Doroneuria baumanni, and Pteronarcys princeps ) and dipterans ( Cryptolabis sp.). Common taxa hatching in late spring or summer are the plecopteran Malenka ( californica? ) and the trichopterans Arctopsyche grandis and Rhyacophila acropedes . Several bivoltine and multivoltine ephemeropterans ( Baetis devinctus and B. tricaudatus ) and dipterans ( Simulium spp. and Chironomidae) have summer cohorts. Taxa hatching in late summer or autumn and most abundant in autumn include ephemeropterans ( Baetis spp., Ephemerella infrequens, Epeorus dulciana, Ironodes lepidus , and Paraleptophlebia pallipes ), trichopterans ( Hydropsyche oslari, Lepidostoma spp., Glossosoma califica, Micrasema sp., Brachycentrus americanus, Neophylax sp., and Rhyacophila vaccua ) and dipterans ( Antocha monticola, Pericoma sp., and Chironomidae). Major recurring events that may influence life history patterns and structure of the benthic insect community are (1) near-freezing, nighttime winter water temperatures and occasional anchor ice, (2) a prolonged period of high discharge in late spring and early summer (3) a brief summer, and (4) a prolonged period of moderate stream discharge in autumn when the substratum is stable and food is abundant.     

Demographic characteristics,seasonal range and habitat topography of Balkan chamois population in its southernmost limit of its distribution (Giona mountain,Greece)

The annual range of Balkan chamois (Rupicapra rupicapra balcanica) in Giona mountain was found to be 5502 ha, with a low population density (2 individuals/100 ha). Seasonal range patterns varied significantly, with a minimum extent in summer and a maximum in winter (30% and 79% of the annual range, respectively). Summer stress and the rutting period might be associated with the observed aggregated distributions during the summer and autumn (core areas of 28% and 22% of seasonal ranges, respectively, defined after the Fixed Kernel Density Estimator). Chamois were found to use significantly lower altitude habitats in winter (1212 m) than in summer (2223 m), and significantly steeper slopes in winter (35°); aspect was not found to have a significant effect on habitat use. Population structure consisted of kids (21%), yearlings (8%), females (35%) and males (36%). Conservation management for the species should consider poaching, livestock competition and global warming.     

Field studies of Cybocephalus nigriceps nigriceps (J. Sahlberg) (Coleoptera: Cybocephalidae) in Israel

Summary

Cybocephalus nigriceps nigriceps (J. Sahlberg) reproduces in Elat (the Arava region of Israel) during spring and summer. Eggs and larvae are present on date palms during these seasons only, whereas adults occur in the grove throughout the year. The adult population reaches its peak in mid-summer and decreases considerably during spring and autumn. Two main locations in which adults occur during the seasons, were found on date palm trees.

Due to the lack of reproduction and activity during autumn and winter, the predator takes almost no part in the biological control of the parlatoria date scale in these seasons.