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The length of gestation is the number of days between fertilization and parturition, and the length of lactation is the number of days between parturition and weaning. Determination of these lengths is difficult for ground-dwelling squirrels such as prairie dogs, marmots, and ground squirrels that usually copulate, give birth, and nurse offspring underground. For Gunnison's prairie dogs (Cynomys gunnisoni), the mean +1 SD length of gestation is 29.3 ? 0.53 days (n = 124). The approximate length of lactation, estimated from the mean +1 SD duration between parturition and the first emergence of juveniles from the natal burrow, is 38.6 ? 2.08 days (n = 112). Published in Journal of Mammalogy, volume 78, issue 1, on...
Areas occupied by white-tailed prairie dogs (WTPD; Cynomys leucurus) and Gunnison's prairie dogs (GPD; C. gunnisoni) are not well-known in Colorado (USA) and elsewhere. Suitable methodology for monitoring changes in populations of WTPD and GPD over broad areas also has not been well established. We evaluated occupancy modeling methodology to establish baseline occupancy rates for WTPD and GPD in Colorado. We estimated that WTPD occupied 24.1% (SE = 12.8) of 47,710 0.25-km2 plots and GPD occupied 7.5% (SE = 1.3) of 158,225 0.25-km2 plots in Colorado during 2004 and 2005. Areas reported as colonies in the Colorado Division of Wildlife's database were not good predictors of WTPD and GPD occupancy. Occupancy rates were...
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A plague (Yersinia pestis) epizootic spread through Gunnison's prairie dogs (Cynomys gunnisoni), and possibly other rodent species, in the Moreno Valley in north-central New Mexico between winter 1984-1985 and autumn 1987. We observed the progress of the epizootic and subsequent population recovery at four prairie dog towns within the valley during this period. At two towns (Midlake and Val Verde) the prairie dogs were marked prior to the epizootic. At two additional towns (Vega and South Entrance) prairie dogs were marked following the epizootic. In 1988, a second epizootic occurred at Vega. One hundred thirty-nine serum samples were collected from prairie dogs and other rodents and 1,750 fleas were collected from...
I measured rates of growth of individual Gunnison's prairie dogs (Cynomys gunnisoni) at three towns in the Moreno Valley, New Mexico; at an established prairie dog town (site I) prior to a plague (Yersinia pestis) epizootic and at two towns reestablished after the epizootic (sites 2 and 3). Populations declined by >99% during rile epizootic. After the epizootic, adults had greater mass, and juveniles grew faster than before. At sites 2 and 3, juveniles had high interyear survival (39%), whereas at site I, prior to plague, survival of juveniles was 17%. At sites 2 and 3, yearlings bred, whereas they did not al site 1. Mean litter size near the end of lactation was 1.5 at site 1 and 5.0 at sites 2 and 3. Application...
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This study addressed the initial effects of a reintroduction of Gunnison's prairie dogs (Cynomys gunnisoni) on resident small mammal and plant communities on the Sevilleta National Wildlife Refuge (SNWR), New Mexico. In spring 1997, 60 prairie dogs (36.8 kg live mass) were introduced onto a former prairie dog colony in a desert grassland site. Small mammals and vegetation were sampled on both a treatment (reintroduction site) and a control site (without prairie dogs) before and after the prairie dogs were reintroduced. We tested for differences in small mammal and plant community change during the 1st year of the colony's existence using repeated measures analysis of variance. Although prairie dog biomass was ca....
Because most animals copulate surreptitiously, estimates of male and female copulatory success are elusive. Here I describe six distinctive behaviors that coincide with underground copulations of Gunnison's prairie dogs (Cynomys gunnisoni): the underground consortship itself, inordinate male attention toward the estrous female, self-licking of genitals, dustbathing, the mating call, and late final submergence of the estrous female. These diagnostic behaviors allowed me to identify sexual partners for 308 females that came into estrus during a 7-year study. Published in Journal of Mammalogy, volume 79, issue 3, on pages 887 - 897, in 1998.
Of the 3 major factors (habitat loss, poisoning, and disease) that limit abundance of prairie dogs today, sylvatic plague caused by Yersinia pestis is the I factor that is beyond human control. Plague epizootics frequently kill > 99% of prairie dogs in infected colonies. Although epizootics of sylvatic plague occur throughout most of the range of prairie dogs in the United States and are well described, long-term maintenance of plague in enzootic rodent species is not well documented or understood. We review dynamics of plague in white-tailed (Cynomys leucurus), Gunnison's (C gunnisoni), and black-tailed (C ludovicianus) prairie dogs, and their rodent and flea associates. We use epidemiologic concepts to support...
Gunnison's prairie dogs (Cynomys gunnisoni) are social North American ground squirrels whose social system has been shown to vary with food resource distributions, as predicted by the habitat variability-mating system model. We expanded this model to include the effects of variations in population densities, in addition to resource distributions, on both the social system and the individual mating strategies of Gunnison's prairie dogs. Specifically, we predicted that monogamy would be associated with uniform resources, regardless of population density, giving way to polygyny with increasing resource patchiness at intermediate densities, and to multiple males and females at high population densities. In addition,...
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The influence of landscape spatial structure on ecological processes has recently received much attention. Comparisons are made here between the spatial structure of grasslands, and active and extirpated Gunnison's prairie dog (Cynomys gunnisoni Hollister) towns at the Petrified Forest National Park, Arizona, U.S.A. The spatial structure of bare ground was quatified using a box-counting technique to extract landscape fractal dimensions, D, and bare-ground patch size. These landscapes are fractal, and active prairie dog towns had higher fractal dimensions, i.e. a more homogeneous spatial structure as D approaches 2, than inactive towns, which had higher fractal dimensions than unmodified grasslands. Morisita's index...
The use of molecular techniques for the assessment of familial relationships among social species of mammals has become relatively commonplace. However, some species represent poor candidates for such studies due to naturally low levels of genetic diversity, leading to unacceptably large standard errors associated with estimates of relatedness. Here, we report on a preliminary study of genetic diversity within two populations of a social species of ground squirrel, Gunnison's prairie dog (Cynomys gunnisoni) using DNA fingerprinting. We observed low levels of diversity in the form of large mean coefficients of genetic similarity among individuals occupying the same population. Overall similarity, determined from...
Mating system characterizations have been hindered by difficulties in accurately assigning parentage to offspring. We investigated the relationship between social assemblages and mating relationships in a territorial harem polygynous mammal, the Gunnison's prairie dog, using a combination of behavioral and molecular analyses. We demonstrate multiple paternity and an extraordinarily high incidence of extraterritorial fertilizations (i.e., 61% of all progeny), in combination with the existence of female kin groups. On this basis, we conclude that social assemblages alone provide a poor description of the Gunnison's prairie dog mating system, and suggest several potential reasons for the maintenance of territoriality...
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Previous studies have shown that landscape structure influences animal movement and population structure. In this study, we show an indirect interaction between beetles and prairie dogs due to prairie dog ecosystem engineering. Gunnison's prairie dog (Cynomys gunnisoni Hollister) towns have more bare ground and are structurally less complex than adjacent unmodified grasslands. This results in bare ground facilitating beetle movement. Differences in landscape structure between prairie dog towns and unmodified grasslands had a significant effect on the movement of the darkling beetle, Eleodes hispilabris Say. Beetle movement tended to be more linear (pathway fractal dimension approached 1) on prairie dog habitats...
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I examined dispersal and social organization of Gunnison's prairie dogs (Cynomys gunnisoni) for 7 years at Petrified Forest National Park, Arizona. Within colonies, individuals lived in harem-polygynous family groups called clans. The number of clans at the study site each year ranged from 21 to 23, with a mean of 22.3. Clan size (the number of adults living in the same territory) ranged from I to 19, with a mean of 5.30. Clans contained 1.06 +/- 0.39 (SD) breeding males,, 3.01 +/- 2.08 breeding females, and 1.23 +/- 1.65 nonbreeding yearling males. Some clams contained two breeding males, and others contained no resident breeding male. The area of clan territories ranged from 0.16 ha to 1.82 ha, with a mean of...
Few studies have experimentally tested the resource dispersion hypothesis (RDH). In this study, I tested whether space use and social organization of Gunnison’s prairie dog responded to changes in the dispersion and abundance of resources. Food manipulations were carried out during the reproductive and nonreproductive seasons across 2 years. Gunnison’s prairie dog adults responded to the experiments by decreasing territory size as food became patchier in space and time. Both males and females modified their home ranges, with no detectable difference between sexes, either prior to or during the experiments. As food became patchier in space and time, the spatial overlap of adults increased, whereas it decreased...
Long-term research with marked individuals shows that black-tailed, Gunnison's, and Utah prairie dogs (Sciuridae: Cynomys ludovicianus, C. gunnisoni, and C. parvidens) all reproduce slowly, despite claims of ranchers and early naturalists. Five factors are responsible for the slow reproduction. First, survivorship in the 1st year is <60% for all 3 species, and it remains low in later years. Second, even under optimal conditions, females of all 3 species produce only 1 litter/year. Third, the percentage of males that copulate as yearlings is only 6%, 24%, and 49% for black-tailed, Gunnison's, and Utah prairie dogs, respectively. The percentage of females that copulate as yearlings is only 35% for black-tailed prairie...
Available information on the status, of the western Burrowing Owl (Athene cunicularia hypugaea) in Arizona is limited. To determine its current status, I sent out questionnaires, made personal contacts, conducted field observations, and searched the literature. These data indicated that relatively little is known in Arizona about this uncommon species. This paper summarizes existing information on the Burrowing Owl in Arizona and provides baseline information for future studies. Location records suggest that this species is a widespread, albeit uncommon, bird in Arizona. The data compiled during this study are still not adequate to assess the status of Burrowing Owls in Arizona as of 1998. An annotated bibliography...
Previous studies of Gunnison's prairie dogs, Cynomys gunnisoni, have reached different conclusions about the factors influencing sociality in this species. In this study I tested whether Gunnison's prairie dog social structure was resource-based or whether male mating strategies drive the organizational patterns observed. Group size, where the term group refers to individuals occupying the same territory, was predicted by territory size and density of food available. The spatial overlap of adults within territories was positively correlated with spatial patchiness of food resources. All group members participated in territory defense, although adult males engaged in significantly more intergroup aggressive interactions....
Body mass is sexually dimorphic and varies seasonally for all 5 species of prairie dogs (Sciuridae: Cynomys), as shown by data from live individuals over a period of 28 years (1974–2001; n = 16,447 body masses). Sexual dimorphism (i.e., body mass of males as percentage of body mass of females) during the breeding season is 105% for black-tailed prairie dogs, 127% for Utah prairie dogs, 131% for Gunnison's prairie dogs, and 136% for white-tailed prairie dogs. Sexual dimorphism is minimal at the end of the breeding season, when exhausted males are thin and early-breeding females are heavy with pregnancy. Sexual dimorphism is maximal at weaning, when rested, well-fed males are heavy and females are emaciated from...
Few studies have experimentally tested the resource dispersion hypothesis (RDH). In this study, I tested whether space use and social organization of Gunnison?s prairie dog responded to changes in the dispersion and abundance of resources. Food manipulations were carried out during the reproductive and nonreproductive seasons across 2 years. Gunnison?s prairie dog adults responded to the experiments by decreasing territory size as food became patchier in space and time. Both males and females modified their home ranges, with no detectable difference between sexes, either prior to or during the experiments. As food became patchier in space and time, the spatial overlap of adults increased, whereas it decreased as...
Few studies have experimentally tested the resource dispersion hypothesis (RDH). In this study, I tested whether space use and social organization of Gunnison?s prairie dog responded to changes in the dispersion and abundance of resources. Food manipulations were carried out during the reproductive and nonreproductive seasons across 2 years. Gunnison?s prairie dog adults responded to the experiments by decreasing territory size as food became patchier in space and time. Both males and females modified their home ranges, with no detectable difference between sexes, either prior to or during the experiments. As food became patchier in space and time, the spatial overlap of adults increased, whereas it decreased as...
map background search result map search result map Dynamics of plague in a Gunnison's prairie dog colony complex from New Mexico The Gunnison's prairie dog structures a high desert grassland landscape as a keystone engineer Philopatry, Dispersal, and Social Organization of Gunnison's Prairie Dogs Responses of small mammals and vegetation to a reintroduction of Gunnison's prairie dogs Prairie dog engineering indirectly affects beetle movement behavior Dynamics of plague in a Gunnison's prairie dog colony complex from New Mexico The Gunnison's prairie dog structures a high desert grassland landscape as a keystone engineer Philopatry, Dispersal, and Social Organization of Gunnison's Prairie Dogs Prairie dog engineering indirectly affects beetle movement behavior Responses of small mammals and vegetation to a reintroduction of Gunnison's prairie dogs