Killing technique of North American badgers preying on Richardson's ground squirrels

2001 ◽  
Vol 79 (11) ◽  
pp. 2109-2113 ◽  
Author(s):  
Gail R Michener ◽  
Andrew N Iwaniuk
Keyword(s):  
North American ◽  
Prey Size ◽  
Ground Squirrels ◽  
Thoracic Cavity ◽  
Internal Organs ◽  
Small Prey ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Southern Alberta

Carcasses of 13 Richardson's ground squirrels (Spermophilus richardsonii) cached during autumn by North American badgers (Taxidea taxus) in southern Alberta, Canada, were inspected to determine the capture and killing technique. Regardless of prey size (251–651 g) or torpor status (normothermic or torpid), badgers killed ground squirrels with a single grasping bite directed dorsally or laterally to the thorax. The canines and third upper incisors of badgers generally bruised the skin without puncturing it, but caused extensive hematomas on the thoracic musculature and penetrated between the ribs, with associated breakage of ribs and hemorrhaging in the thoracic cavity. Internal organs and bones other than ribs were usually not damaged. Thoracic bites, rather than nape or throat bites, are used by several mustelids, including North American badgers, when capturing small prey (<10% of the predator's mass).

Description of Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae): a parasite of the badger Taxidea taxus with experimental transmission to the Richardson's ground squirrel, Spermophilus richardsonii

1983 ◽  
Vol 61 (2) ◽  
pp. 370-377 ◽  
Author(s):  
Richard J. Cawthorn ◽  
Gary A. Wobeser ◽  
Alvin A. Gajadhar
Keyword(s):  
Ground Squirrel ◽  
Prepatent Period ◽  
Ground Squirrels ◽  
Intermediate Hosts ◽  
Patent Period ◽  
Sporocyst Residuum ◽  
Experimental Transmission ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Large Round

Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae) is an heteroxenous coccidium with badgers (Taxidea taxus) as natural and experimental definitive hosts and Richardson's ground squirrels (Spermophilus richardsonii) as experimental intermediate hosts. Free sporocysts (10.2 × 8.0 μm with a large, round sporocyst residuum consisting of a single refractile granule), obtained from intestinal scrapings of badgers (carcasses frozen 2 years at −20 °C), were orally administered to juvenile Richardson's ground squirrels. Acute fatal sarcocystosis developed in some squirrels at 11–13 days postinoculation (p.i.). Meronts (second generation) were present 9–12 days p.i. in the vascular endothelium of many tissues (especially the lungs). Cysts developed in skeletal muscle, contained metrocytes (7 × 5 μm) 30 days p.i., and beginning 46 days p.i., bradyzoites (12.0 × 3.5 μm) were present. Cysts were macroscopic as early as 258 days p.i. Squirrel carcasses containing cysts (76 days p.i.) of S. campestris sp. n. were fed to Sarcocystis-free badgers. The prepatent period was 9 days and the patent period at least 13 days. Both badgers were ill early in the patent period and passed unformed feces during the patent period. Free sporocysts were 10.2 × 8.0 μm and each had an elongate sporocyst residuum containing numerous small refractile granules.

Effect of age and parity on weight gain and entry into hibernation in Richardson's ground squirrels

1978 ◽  
Vol 56 (12) ◽  
pp. 2573-2577 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Weight Loss ◽  
Weight Gain ◽  
Survival Rate ◽  
Weight Maintenance ◽  
Ground Squirrels ◽  
Winter Survival ◽  
Delayed Entry ◽  
Spermophilus Richardsonii ◽  
Southern Alberta ◽  
Effect Of Age

Weight gain and time of entry into hibernation were recorded for nonparous yearling, parous yearling, and parous 3-year-old Spermophilus richardsonii in southern Alberta in 1977. Nonparous squirrels steadily gained weight over the 12-week period between emergence from hibernation and immergence into hibernation. The weight pattern of parous squirrels exhibited a sub-cycle of weight gain, weight loss, and weight maintenance associated with pregnancy, parturition, and lactation resulting in delayed attainment of prehibernation peak weights and delayed entry into hibernation. There was no difference in time of emergence of parous and nonparous females in the subsequent spring. Age affected rates of post lactation weight gain such that the oldest mothers remained active longest but attained the lowest prehibernation weights. Oldest mothers had the lowest over-winter survival rate.

Factors associated with nest- and roost-burrow selection by burrowing owls (Athene cunicularia) on the Canadian prairies

2005 ◽  
Vol 83 (10) ◽  
pp. 1373-1380 ◽  
Author(s):  
Ray G Poulin ◽  
L Danielle Todd ◽  
Kimberly M Dohms ◽  
R Mark Brigham ◽  
Troy I Wellicome
Keyword(s):  
Ground Squirrels ◽  
Athene Cunicularia ◽  
Canadian Prairies ◽  
Burrowing Owls ◽  
Burrowing Owl ◽  
Factors Associated ◽  
Crop Fields ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Selection Of

We examined nest- and roost-burrow characteristics from a declining population of burrowing owls (Athene cunicularia (Molina, 1782)) in Saskatchewan. Between 1992 and 2003, 84% of the 584 nests we found were in grassland pastures, even though these pastures constituted only 7% of the potentially available nesting area within our study area. In contrast, less than 3% of nests were in crop fields, despite these fields comprising 90% of the potentially available area. Within grassland pastures, owls selected nest burrows in areas with a higher density of burrows within 75 m (11.1 burrows/ha) compared with non-nest burrows of similar dimensions (5.6 burrows/ha). Richardson's ground squirrels (Spermophilus richardsonii (Sabine, 1822)) and badgers (Taxidea taxus (Schreber, 1777)) are the primary excavators of suitable nesting burrows in prairie Canada. In our study area, burrowing owls chose to nest and roost in badger-sized burrows, selecting those with taller tunnel entrances and soil mounds relative to unused burrows. We suggest that management for burrowing owl nesting habitat in Canada should consider the owls' avoidance of crop fields and their preference for grassland pastures. Managers should also consider the owls' apparent preference for nesting in areas of high burrow densities and their selection of badger-sized burrows for nesting and roosting.

Restudy of Spirura infundibuliformis McLeod, 1933 (Nematoda: Spiruroidea) from Spermophilus richardsonii, with observations on its development in insects

1993 ◽  
Vol 71 (9) ◽  
pp. 1869-1873 ◽  
Author(s):  
R. C. Anderson ◽  
E. T. Barnes ◽  
C. M. Bartlett
Keyword(s):  
Ground Squirrels ◽  
Infective Stage ◽  
Ambient Temperatures ◽  
Spermophilus Richardsonii ◽  
Southern Alberta

A redescription is provided of Spirura infundibuliformis from the stomach of ground squirrels, Spermophilus richardsonii, in southern Alberta, Canada; Spirura leucurusi Babero, 1973 is regarded as a synonym. Spirura infundibuliformis is distinguished from most members of Spirura by the presence of 9–13 pairs of preanal papillae; 20 other species described in the genus have only 4, rarely 5, pairs. Spirura infundibuliformis developed at ambient temperatures (20–30 °C) to the infective stage in 11–12 days in grasshoppers common on the prairies (Melanoplus infantilis, Aeropedellus clavatus, Aulocara elliotti, and Camnula pellucida), where the ground squirrels were collected, as well as in laboratory-reared crickets (Acheta pennsylvanicus).

Effect of climatic conditions on the annual activity and hibernation cycle of Richardson's ground squirrels and Columbian ground squirrels

1977 ◽  
Vol 55 (4) ◽  
pp. 693-703 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Rocky Mountains ◽  
Climatic Conditions ◽  
Ground Squirrels ◽  
Active Season ◽  
Southern Alberta ◽  
Annual Activity ◽  
The Times ◽  
Columbian Ground Squirrels ◽  
Spring Emergence ◽  
Species Ecology

In 1975 and 1976 the times of spring emergence, breeding, and entry into hibernation were compared for Spermophilus richardsonii and S. columbianus in an area of sympatry in the foothills of the southern Alberta Rocky Mountains. Both species emerged earlier in 1976, which had a warmer than normal spring, than in 1975, which had a cooler than normal spring. In both years S. richardsonii emerged earlier than S. columbianus and remained active longer. Juvenile S. richardsonii entered hibernation when 17–20 weeks old whereas juvenile S. columbianus were 10–11 weeks old. Yearling S. richardsonii bred, whereas yearling S. columbianus did not. Breeding success affected the time of entry into hibernation but not the time of emergence from hibernation in the next spring. A possible relationship between the periodic arousals during hibernation and the emergence pattern of squirrels in spring is discussed. The significance of flexibility of spring emergence, length of the active season, and age at breeding to survival and species ecology is considered.

Effects of central injection of biogenic amines during arousal from hibernation

1979 ◽  
Vol 236 (3) ◽  
pp. R162-R167 ◽  
Author(s):  
J. D. Glass ◽  
L. C. Wang
Keyword(s):  
Ambient Temperature ◽  
Specific Heat ◽  
Biogenic Amines ◽  
Heat Production ◽  
Ground Squirrels ◽  
Spermophilus Richardsonii ◽  
Simultaneous Measurements ◽  
Apparent Specific Heat ◽  
Intracerebroventricular Injections ◽  
Made In

Simultaneous measurements of heat production (HP) and heat loss (HL) and brain and rectal temperatures were made in Richardon's ground squirrels (Spermophilus richardsonii) rewarming from hibernation at an ambient temperature of 6.0 +/- 0.5 degrees C. Calculations from HP and HL measurements from control animals showed that due to differential rewarming, there was a reduction of apparent specific heat of the animal to 0.59 cal/g. degrees C. This resulted in an energy saving of 30%. Three intracerebroventricular injections of 5-hydroxytryptamine (5-HT) of 56 microgram each at brain temperatures of 10, 20, and 30 degrees C caused initial suppression of HP and a greater overall HL, which resulted in a slower rate of arousal as compared to the controls. Injections of norepinephrine (NE) of 12.5 microgram each at similar brain temperatures caused a greater rate of HP, which resulted in a faster rate of arousal as compared to the controls. The respective actions of 5-HT and NE on thermoregulation during rewarming are similar to those in some euthermic hibernators and nonhibernating species. Our data indicated that these substances evoke thermoregulatory responses during arousal in much the same manner as during normothermia.

Accelerated circannual cycles in ground squirrels, Spermophilus richardsonii, kept in constant conditions

1983 ◽  
Vol 61 (8) ◽  
pp. 1765-1770 ◽  
Author(s):  
Roman B. Melnyk
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Ground Squirrels ◽  
Food Utilization ◽  
Metabolic Processes ◽  
Reproductive Condition ◽  
Spermophilus Richardsonii ◽  
Upper Limit ◽  
Circannual Cycles

Six- to 8-month cycles of food intake, body weight, moult and reproductive condition in captive Richardson's ground squirrels (Spermophilus richardsonii) kept in 12 h light: 12 h dark and 23 ± 3 °C for over a year are described. A decrease in efficiency of food utilization towards the end of the weight gain period may be associated with metabolic processes which determine an upper limit for body weight. The advantages of this species as a model for the study of spontaneous obesity are discussed.

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