Ochotona Princeps Research Articles

North American Pika ( Ochotona princeps) as a Late Quaternary Biogeographic Indicator Species

Reevaluation of Quaternary sites of fossil pika ( Ochotona) lends no support for the inference that Nearctic pikas were not restricted to rocky habitat. The saxicolous nature of all widespread, isolated populations of extant Nearctic pikas and their closest Palearctic sister taxa support consideration of O. princeps, and perhaps all Nearctic Quaternary Ochotona , as indicators of cool, mesic, rocky situations. As indicators of rocky microhabitat, fossil remains of O. princeps do not require that the entire region was cool and mesic, but only that suitable rocky microhabitat existed in the vicinity. Use of fossil pika dung alone as indicative of pikas in the immediate community is suspect, as the small, round, and buoyant pellets may be transported downslope by hydraulic flushing of talus habitat. Current local elevational lower limits ( E) of appropriate habitat for paleoecological reconstruction at extralimital fossil sites are predicted by the equation: E(m) = 14087 - (56.6)°N - (82.9)°W.

Male-Female Spacing, Territorial Replacement, and the Mating System of Pikas (Ochotona princeps)

Etude du placement de mâles et des femelles de O. princeps pour tester l'hypothese selon laquelle les comportements sociaux influencent le positionnement des territoires d'individus du meme sexe. Le systeme de reproduction de cette espece est examine

Hoary Marmots Attracted to Human Urine Sites

Accounts of foraging behavior in hoary marmots (Marmota caligata) show very similar patterns in colonies from Alaska (Hansen 1975; Holmes 1984a), Montana (Tyser and Moermond 1983), and Washington (Barash 1973,1974; Taulman 1975). All members of a colony have equal access to foraging areas as a result of the high social tolerance between colony members (Barash 1974). Selection of primary feeding areas is influenced by the abundance of preferred plant species and by the proximity of refuge and sleeping burrows (Holmes 1984a). Marmots typically move about while feeding, looking up about once a minute to reconnoiter their surroundings as they chewJ before moving on a few steps (Taulman 1975; Tyser and Moermond 1983; Holmes 1984a). This paper presents new data on hoary marmot feeding behavior at human urine sites. From 18 June through 20 September 1975 I spent 322 hrs observing the behavior of a colony of four adult and three yearling hoary marmots on the south slope of Mt. Cashmere in the Washington Cascades at an elevation of 2200 m (47°32'N, 120°50tW). I observed 19 instances of from one to four marmots at a time feeding at human urine sites. The sites were often bare ground, and the marmots appeared to be nibbling or licking the soil, occasionally scratching at the dirt. While feeding at a latrine site, marmots assumed a characteristic posture seen at no other time. They crouched with the forepaws together under the body in a cat-like stance. A feeding marmot appeared motionless for 5-10 min at a time, not looking up or moving around, as is normally seen in foraging or traveling behavior. Pattie (1967) reported on a group of yellow-bellied marmots (Marmota faviventris) feeding regularly along a roadside where they may have been picking up traces of salt. He substantiated this theory with further observations that yellow-bellied marmots, as well as pikas (Ochotona princeps), golden-mantled ground squirrels (Citellus saturatus) and mule deer (Odocoileus hemionus) visited latrines and ate both dirt and vegetation where humans had urinated. Another researcher (Holmes 1984b) found that hoary marmots would enter traps baited with human urine after the spring thaw, when 14 other previously-taken baits were no longer effective. To test the hypothesis that the approximately 0.7% salt normally found in human urine was the attractive ingredient, I mixed enough salt in 0.5 l of water to produce a slight salty taste and poured this on a plot of bare ground within 30 m of the sleeping burrows. A similar site 1 m from the experimental plot received an equal amount of unsalted water. The next day two marmots, and again seven days later one marmot, fed at the site that had received the salted water. Each marmot showed the same novel feeding behavior as did marmots at urine sites. No marmots were observed to notice the control plot. Hoary marmots presumably obtain salt in trace amounts from rocks and soil, but they are attracted to the higher concentrations available in the soil at human latrines. Normal foraging behavior is not appropriate because of the small size of the urine sites; thus, animals remain stationary when feeding. Urine sites utilized were near the marmots' sleeping burrows since that part of the colony territory provided an excellent vantage point for observations. ThereforeJ marmots feeding at urine sites had a familiar refuge nearby. The fact that the customary head-up alert posture seen during normal foraging was not performed by marmots feeding at urine plots implies the possibility that

Mate choice and reproductive success of pikas

Factors affecting mate choice and female reproductive success were studied in a population of pikas, Ochotona princeps, in northeastern Oregon. Features of the den habitat (number of entrances to the den, size of the surrounding talus, distance to vegetation, amount of grass and forb present) and the mate or potential mate (weight and age) were analysed with respect to their effects on offspring production and survival, maternal survival and female mate choice. Female pikas chose mates primarily on the basis of the type of den available and the distance from the den to vegetation. These features were the primary determinants of the number of young weaned, but had no significant effects on maternal survival. Paternal weight was an important influence on offspring production, but its effect on female fitness was tempered by a negative effect on female survival. Characteristics important to female choice had no significant influence on the survival of young between weaning and natal dispersal and so cannot be considered to be male ‘handicaps’. Male pikas tended to be philopatric so that sons of males with territories that were attractive to females tended to inherit the attractive territories of their fathers. Female choice among pikas is thus best explained by Darwin's and Fisher's theories of intersexual selection.

Cheek-Gland Odors in Pikas (Ochotona princeps): Discrimination of Individual and Sex Differences

Cheek-Gland Odors in Pikas (Ochotona princeps): Discrimination of Individual and Sex Differences

Influence of Refuging Consumers (Pikas: Ochotona Princeps) on Subalpine Meadow Vegetation

Talus slopes in western North America frequently are bordered by vegetation that differs in biomass, cover, height, and species composition from vegetation located farther from talus. These areas are grazed by pikas (Ochotona princeps), which nest in that talus. Foraging theory predicts that pikas will produce a gradient of grazing pressure, which could produce the observed vegetational zonation. In a subalpine meadow in west—central Colorado, pikas produced the predicted gradient of grazing pressure, along which plant groups varied clinally in abundance. The effects of pikas on talus—border vegetation were tested by excluding pikas from small plots at several distances from talus. Vegetational cover and species richness increased in exclosures relative to control plots. These changes in vegetation following exclusion of pikas were greatest near talus and decreased with distance, paralleling the gradient of foraging by pikas. The effect of pika exclusion on cushion plants changed quantitatively and qualitatively with distance from talus and with time since grazing was stopped. These patterns were predicted from a model of the interaction of competition and predation along a gradient of grazing pressure. Mechanisms similar to those proposed for pikas are also expected for other small herbivores that forage from fixed nest sites.

Territorial intrusions by pikas ( Ochotona princeps) as a function of occupant activity

Pikas ( Ochotona princeps) defend individual territories on talus. We tested the short-term stability of pika territories and found that although animals may intrude on the territories of conspecifics at any time, they were much more likely to do so if the occupant was inactive. Pikas usually waited until occupants were unavailable to defend their territory before intruding, apparently to avoid detection and repulsion by the occupant. Intruder avoidance of active occupants was most pronounced among same-sex dyads and non-nearest neighbours. Instances of territory intrusion were most frequent among nearest neighbour heterosexual dyads. Most cases of intrusion appeared to be related to eventual relocation of territories, deterring settlement of unfamiliar conspecifics on nearby vacant territories, and/or increasing familiarity with nearest neighbours of the opposite sex.

Foraging Behavior of the Pika (Ochotona princeps), with Comparisons of Grazing versus Haying

Pikas ( Ochotona princeps ) inhabit areas with talus and forage on surrounding vegetation. Their foraging behavior was consistent with several predictions of central place foraging theory. Intensity of foraging decreased with distance from talus, whereas selectivity increased. Plant abundance and species richness increased with distance from talus. Differences between grazing (direct consumption of plants) and haying (harvesting and caching plants) behaviors appear to reflect differences in costs and benefits between these activities. Higher proportions of forbs and tall grasses were hayed than grazed. When haying, pikas traveled significantly farther into the meadow from the talus border than when grazing. Pikas grazed year round, but hayed only during a restricted time (July through September) when plant biomass had peaked.

Population Density and Fluctuations of Pikas (Ochotona princeps) in Colorado

Pika populations in the Colorado Rockies have shown relatively consistent densities and stability over eight years of study. At three different sites, mid-August densities varied from 3.4 to 9.8 pikas/ha, and annual population fluctuations averaged less than 30%. In contrast, many other small mammal populations, including those of Microtus, Mus, Clethrionomys, Apodemus, Lemmus, Lepus and Oryctolagus show much greater variability in population density, and often show mean annual fluctuations from 60 to over 100%. We hypothesize that the relative stability of pika populations of moderate size is a result of their food-based territorialism coupled with parent-offspring and sibling relationships. Territorialism places behavioral limits on population densities whereby juveniles either disperse or remain philopatric depending upon density-related social behaviors.

Low levels of genetic variability in pikas from Colorado

Genetic variability at 27 loci was analyzed in four populations of pikas (Ochotona princeps) from Colorado. Estimates of mean heterozygosity [Formula: see text] ranged from 0.5 to 1.4%. These results are among the lowest estimates of [Formula: see text] reported for a mammal having a broad distribution, and are the lowest reported for a lagomorph. Data from this study and others estimate [Formula: see text] as 0.71% for pikas from Colorado. Founder effect, followed by drift occurring in small isolated populations during postglacial shifts in the range of the pika, is the most likely explanation for low estimates of genetic variability in pikas from Colorado.

Growth of Pikas (Ochotona princeps) in Colorado

Journal Article Growth of Pikas (Ochotona princeps) in Colorado Get access Steven C. Golian, Steven C. Golian Department of Environmental Population and Organismic Biology, University of Colorado, Boulder, CO 80309 Search for other works by this author on: Oxford Academic Google Scholar Molly R. Whitworth Molly R. Whitworth Department of Pathology, Johns Hopkins University, Baltimore, MD 21205 Search for other works by this author on: Oxford Academic Google Scholar Journal of Mammalogy, Volume 66, Issue 2, 31 May 1985, Pages 367–371, https://doi.org/10.2307/1381250 Published: 31 May 1985 Article history Received: 02 February 1984 Accepted: 22 August 1984 Published: 31 May 1985

Analysis of the vocal repertoire of adult pikas: ecological and evolutionary perspectives

Analyses of vocalizations and behaviour of field and captive populations of pikas ( Ochotona princeps) indicate that adults use at least nine structurally distinct acoustic signals in a variety of contexts. The pika acoustic repertoire more closely resembles in size and form the repertoires of many rodent species rather than those of other lagomorphs. The evolution of an elaborate acoustic repertoire has been influenced both by the pikas' atypical social organization and the visually disruptive environment in which they live.

The Function of the Pika Short Call in Individual Recognition

Abstract and SummaryTwo populations of individually marked pikas (Ochotona princeps) were studied on Niwot Ridge, Boulder County, Colorado, U.S.A., to determine if these lagomorphs are able to, and actually do, recognize other individuals through the use of vocal cues contained in the short call. Discriminant function analysis demonstrated that short calls are individually distinct in structure. Furthermore, pikas responded differentially to naturally occurring calls from different individuals and recognition appears to be possible solely through the use of vocal cues contained within the short call.Pikas also discriminated between playbacks of familiar and unfamiliar short calls. The strength of response appears related to the level of competition and the relative amount of threat that a familiar or unfamiliar pika represents to the responding individual.

The role of an acoustic display in territorial maintenance in the pika

Field experiments were performed on pikas (Ochotona princeps) to determine the role of their short call in the maintenance of territories. Removal of a resident resulted in significant increase in intrusions by adjacent pikas and the persistence of the intruder within the vacant territory. However, replacing a removed resident with its short call was effective in preventing a significant increase in intrusions.

Sex differences in the ontogeny of social behavior in pikas: possible relationships to dispersal and territoriality

A laboratory study on the ontogeny of social behavior in pikas (Ochotona princeps), an alpine lagomorph, was conducted to determine the role of early relationships between adult females and young and among siblings in the development of territorial and dispersal behaviors. Sex differences during development were examined because field studies have reported greater dispersal distances in young females than young males. At birth, females were significantly heavier than males. There were no sex differences in nursing frequency until after the 2nd week of age, when males initiated more nursing attempts than females. By the end of the weaning period (weeks 5 and 6), adult females became non-interactive with young, but aggression of young toward littermates and the mother increased until the eighth week. At this time, young males outweighed their sibling females. Young were dominant over their mothers by the age of 5 weeks, and young males were dominant over their sibling females. Sex differences were observed in aggression, scent-marking, exploratory activity, and submissive vocalizations, with higher rates in young males, except for submissive vocalizations, which were higher in females (Table 2). Vocalizations and scent-marking behavior increased over time, and were positively correlated with interaction rates. These data support the hypothesis that female young disperse farther than male young largely as the result of unsuccessful competition with male siblings for available territories close to the birthplance. A dispersal strategy for pkkas is proposed.

Maternal care and behavioural development in pikas Ochotona princeps

A laboratory study on the pika, Ochotona princeps, an alpine lagomorph, was conducted to examine the ontogeny of social organization in this species. Thirty-six wild-caught adult females and their laboratory-born litters were observed for 1182 h from birth of the young to 3 months of age. This paper presents the first quantitative results and description of maternal care and the development of behaviour in young pikas. Analysis of maternal behaviour revealed that pikas exhibit an absentee maternal care system, characteristic of the order Lagomorpha. Females visited the nest once every 2 h, nursing for an average of 10 min each visit. All maternally-initiated nursing behaviours declined to zero by the sixth week. Retrieval of neonates was not observed. Young pikas are born altricial and slightly haired, with eyes closed and teeth fully erupted. Pikas were weaned by the end of the sixth week, at an average weight of 75 g. The first adult behaviours observed were scent-marking, alarmcalling and aggression; sexual behaviour was not well-developed by the end of the 3-month observation period. During the period of weaning conflict, maternal aggression peaked, as nursing attempts by the young increased. During this time, young males made more nursing attempts than did sibling females and adult females were more aggressive toward young males than toward females. After weaning, mothers became non-interactive with young, but the aggression of young toward littermates and the mother increased until the eighth week, when overall aggression levelled off. Vocalizations and scent-marking behaviour increased over time, and they were positively correlated with interaction rates. By the end of 3 months, the young had reached adult weight and were extremely territorial and aggressive toward conspecifics.

The Genus Schizorchis (Cestoda: Anoplocephalidae) in Eurasian Pikas, Ochotona spp. (Lagomorpha: Ochotonidae), with Descriptions of New Species

Pikas, Ochotona hyperborea (Lagomorpha: Ochotonidae), were collected at six localities in northeastern Siberia (Magadansk Oblast') and examined for helminths. Cestodes of the genus Schizorchis (Anoplocephalidae) were found at two localities. Schizorchis yamashitai is reported for the first time from the Eurasian continent, and S. ryzhikovi n. sp. is described. In addition, S. nepalensis n. sp. is described from 0. roylei in Nepal. The relationships and zoogeography of these cestodes are discussed. The mammalian genus Ochotona Link (Lagomorpha: Ochotonidae) is represented in the Nearctic by two species, and in the Palaearctic by approximately 17 (cf. Honacki et al., 1982). As a group, pikas have a distinctive helminth fauna, composed mainly of host-specific genera. Of three such genera of cestodes, only one, Schizorchis Hansen, 1948, is known to be polytypic, with two species each in North America and Eurasia. One palaearctic species, S. yamashitai Rausch, 1963, is known only from Ochotona hyperborea (Pallas) on the island of Hokkaido. The second, S. altaica Gvozdev, 1951, has been reported from pikas of various species on the Eurasian continent. However, discrepancies in the descriptions of cestodes identified as S. altaica suggest that more than one species is involved. Fieldwork undertaken by us in northeastern Siberia during four years (197577 and 1979) provided the opportunity to collect pikas at various localities, and from these animals, we obtained cestodes representing two species of Schizorchis. The availability of additional comparative material permitted a reassessment of taxa occurring in Eurasian pikas, including cestodes from Ochotona roylei (Ogilby), from Nepal, identified tentatively by Rausch & Ohbayashi (1974) as S. altaica. The results of this work are reported in the present paper, and two additional species of Schizorchis are described. 1 Publication costs, in part, are being met by a grant from the Spencer-Tolles Fund of the American Microscopical Society. 2 Fieldwork in northeastern Siberia was carried out under the U.S.A./U.S.S.R. Environmental Protection Treaty, Area V, Subproject A-3, Diseases and Parasites of Wildlife. Logistic support in the Soviet Union was provided by the Institute of Biological Problems of the North, Far-Eastern Scientific Center, Academy of Sciences of the U.S.S.R., Magadan, under the direction of Dr. V. L. Kontrimavichus. 3 Present address: Gor'kii Institute of Veterinary Research, Gor'kii N2, U.S.S.R. TRANS. AM. MICROSC. Soc., 103(2): 144-156. 1984. ? Copyright, 1984, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.159 on Fri, 09 Dec 2016 05:19:02 UTC All use subject to http://about.jstor.org/terms VOL. 103, NO. 2, APRIL 1984 MATERIALS AND METHODS With the exception of the specimens from Ochotona roylei, which had been preserved in situ, the cestodes were allowed to relax in water, fixed in a hot solution of 10% formalin, stained in acetic carmine or hematoxylin, dehydrated, and cleared in terpineol. After removal to xylene, the tegument and underlying muscle layers were removed from part or all of one strobilar surface of selected specimens, which then were mounted permanently. Also, some previously mounted cestodes were removed from the slides, rehydrated and restained if necessary, and similarly processed. Comparative material consisted of the following: Schizorchis ochotonae Hansen, 1948 from Ochotona princeps (Richardson), near Jackson, Wyoming, 2; S. altaica Gvozdev, 1951 from 0. rutila (Severtsov), Kazakhstan (leg. E. V. Gvozdev), 2; S. caballeroi Rausch, 1960 from 0. collaris (Nelson), various localities in Alaska, 20, and from 0. princeps, Lane County, Oregon (leg. C. Maser), 2; and S. yamashitai Rausch, 1963 from 0. hyperborea, Lake Shikaribetsu, Hokkaido, 7.

Spatial Relationships and Social Organization in Adult Pikas: A Facultatively Monogamous Mammal

Abstract and SummaryAdult spatial relationships and social organization in a marked population of alpine mammals, the pika (Ochotona princeps), were studied over a 3‐year period in the Rocky Mountains of Colorado. Home range size, distances between centers of activity of dyads, and weighted overlaps of home ranges of dyads were used to define space use patterns. Disappearance and establishment of individuals reflected the temporal component of space use. Relative frequencies of foraging (haying and feeding), surveillance, and communication (short calling, long calling, cheek rubbing) behaviors were recorded. Social relationships among adults were defined by agonistic interactions (aggression) and affiliative behaviors (social tolerance, vocal duets, copulations).Males and females occupied individual home ranges of equal size on talus, their obligate habitat type. Adjacent home ranges were normally occupied by pikas of the opposite sex. Replacement of home ranges was always by a member of the same sex as the previous occupant. A high degree of affiliative behavior was expressed between spatially contiguous heterosexual dyads. Aggression was greater among intrasexual than heterosexual dyads, and spatial overlaps among intrasexual conspecifics were less than among heterosexual conspecifics.Ecological constraints, such as the distribution of food (primarily located in meadows adjacent to the talus) and the short summer reproductive season (placing a premium on early appropriately timed litter;;) have apparently led to a facultatively monogamous mating system. Males can neither monopolize essential resources sufficiently to attract several females, nor defend groups of females as social repulsion among females further increases their dispersion.

Responses of pikas (Ochotona princeps, Lagomorpha) to naturally occurring terrestrial predators

The responses of individually marked pikas (Ochotona princeps) to terrestrial predators were investigated in 1980 and 1981 in the Rocky Mountains of Colorado. Pikas uttered short call vocalizations in a variety of contexts: preceding or following an individual's movement, and in response to conspecifics, other nonpredaceous mammals and predators. Adult pikas apparently discriminated contexts in which predators were present by short calling more frequently and for longer duration compared with calling in nonpredator contexts. Short calls uttered by juveniles were similar in all contexts.

Colonization in a pika population: dispersal vs philopatry

Relative tendencies toward dispersal or philopatry in a marked population of alpine mammals, the pika (Ochotona princeps), were investigated over a 3-year period in the Rocky Mountains of Colorado. Home range size, distances between centers of activity of dyads, and weighted overlaps of home ranges of dyads were used to define space use patterns. Disappearance and establishment of individuals reflected the temporal component of space use. Social relationships among conspecifics were defined by agonistic and affiliative behaviors. Home ranges of resident adult males and females were of equal size on talus, the obligate habitat of pikas. Adjacent home ranges were normally occupied by members of the opposite sex, and this spacing apparently results from the balance of agonistic and affiliative behaviors exhibited by nearest-neighbor heterosexual pairs. Most juveniles were philopatric. Throughout the summer they remained on their natal home range where they were involved in both agonistic and affiliative behaviors with their mother and putative father. Most animals that established residency were juveniles, and of these almost all settled within 50 m of their natal home range center. This pattern was independent of population density. Immigrants were met with extreme aggression by resident adults that was not balanced by affiliative behaviors. Few immigrants of either sex successflly established on the study area. Adults occasionally changed home ranges, probably to enhance their chances of mating. Intense aggression directed at unfamiliar animals coupled with the acceptance of spatial overlap of related young throughout the summer apparently promote philopatry in pikas. Philopatric settlement in pikas may lead to incestuous matings and contribute to their low intrapopulation genetic variability.