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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...
We determined sizes of home ranges for pygmy rabbits in southwestern Wyoming and characterized the vegetation within and outside those areas used during winters of 1993 and 1994. Seventy percent of pygmy rabbits used more than one core area within their home range. Habitats within home ranges had less low ground cover and a greater number of wider, taller Artemisia tridentata than did adjacent non-used areas. Pygmy rabbits selectively used dense and structurally diverse stands of A. t. tridentata, which also accumulated more snow than areas of low use. Structure and diversity of vegetation above the snow's surface declined as the season progressed and depths of snow increased. The subnivean environment provided...
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...
ABSTRACT.-Habitaut tilization by Peromyscus boylii, P. maniculatus, and Neotoma stephensi was studied by live trapping marked animals on grids in a variety of local habitats in eastcentral Arizona. None of the species exhibited clear-cut affinities for specific plant taxa; rather, the types of flora used by each species varied from grid to grid. P. boylii tended to use a wide variety of vegetational microhabitats, but almost always was captured in higher frequencies than expected in the commonest type(s) at a locality. P. maniculatus showed much more restricted habitat utilization, but where it did occur, it tended to be captured in the most prevalent vegetation more often than expected. N. stephensi also occurred...
In the third year of my study of social behavior and population dynamics in the Gunnison's prairie dog (Cynomys gunnisoni), one colony was eliminated by sulvatic plague (Yersinia pestis). The passage of plague through prairie dog colonies has been reported previously (Eskey and Haas, 1940; Ecke and Johnson, 1952; Leckleitner et al., 1962, 1968), but only one other colony has been ovserved prior to the onset of a plague outbreak: Clark's (1977) study of white-tailed prairie dogs (Cynomys leucurus). THe present report provides detailed population data prior to and during a plague outbreak in the Gunnison's prairie dog. Published in Journal of Mammalogy, volume 66, issue 1, on pages 194 - 196, in 1985.
ABSTHACT: The voles Microtus montanus, M. longicaudus, M. mexicanus, and AM. pennsylvanicus occur in New Mexico and all reach their distributional limits in the general region. The four species differ in degree of ecological and geographic restriction and in amount of geographic variation. Degree of geographic variation seems to be positively correlated with degree of restriction and isolation. A possible case of character displacement resulting from competition of closely related species is discussed. Historical biogeographic factors possibly leading to the present situation are considered. Published in Journal of Mammalogy, volume 43, issue 2, on pages 154 - 166, in 1962.
Multiple factors likely influence natal dispersal behavior of juvenile mammals, which is typically male-biased. Because of their small body size and specific habitat requirements, pygmy rabbits (Brachylagus idahoensis) are expected to exhibit limited dispersal. We predicted that dispersal would be male-biased, that juveniles born later in the year would disperse farther, and that juveniles would be more likely to disperse away from areas of higher habitat saturation. We used radiotelemetry to study dispersal of 61 juvenile pygmy rabbits (31 males and 30 females) from shortly after emergence from natal burrows (April?July) to the beginning of the next breeding season (mid-March) during 2004?2006. Juveniles dispersed...
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...
Food habits of four rodents (Dipodomys ordii, Onychomys leucogaster, Peromyscus maniculatus, and Spermophilus tridecemlineatus) of a shortgrass prairie ecosystem in northeastern Colorado were studied in 1969 and 1970 through microscopic analysis of stomach contents. Mean per cent volumes of animal matter in diets of these rodents over the entire study were: D. ordii, 4.4 per cent; 0. leucogaster, 73.9 per cent; P. maniculatus, 39.0 per cent; and S. tridecemlineatus, 44.0 per cent. The greatest amount of seasonal variation in per cent volume animal matter in the diet was in P. maniculatus. Animal matter in diets of all four species was composed almost entirely of arthropods and a few parts of vertebrates. The most...
map background search result map search result map Philopatry, Dispersal, and Social Organization of Gunnison's Prairie Dogs Philopatry, Dispersal, and Social Organization of Gunnison's Prairie Dogs