Spatial relationships between swift foxes and coyotes in northwestern Texas

2003 ◽  
Vol 81 (1) ◽  
pp. 168-172 ◽  
Author(s):  
Jan F Kamler ◽  
Warren B Ballard ◽  
Rickey L Gilliland ◽  
Kevin Mote

Interspecific competition among canids can result in mortalities and spatial displacement of smaller canids by larger canids. To investigate mortalities and spatial relationships of swift foxes (Vulpes velox) and coyotes (Canis latrans), we captured and radio-tracked both species at Rita Blanca National Grasslands in northwestern Texas. At least 89% of swift fox mortalities were caused by coyotes, resulting in a relatively low annual survival of 0.47 for swift foxes. Annual home ranges of swift foxes occurred near the periphery and outside coyote home ranges, and did not overlap or only slightly overlapped coyote core areas. Thirty-three of 36 known swift fox dens occurred outside coyote core areas. When swift foxes established dens within coyote core areas (n = 3), they were killed by coyotes shortly thereafter. Our data indicated that spatial displacement of swift foxes was not due to behavioral avoidance of coyotes but rather to increased killing of swift foxes within coyote core areas. Most mortalities caused by coyotes occurred in the immediate vicinity of swift fox dens, suggesting that coyotes made an active effort to kill swift foxes.

2002 ◽  
Vol 80 (11) ◽  
pp. 2024-2029 ◽  
Author(s):  
Travis L Olson ◽  
Frederick G Lindzey

We monitored dispersion patterns of swift foxes (Vulpes velox) for 3 years in shrub-grassland habitats on the margin of the species' geographic range near Medicine Bow, Wyoming. Annual home-range size was 18.6 ± 1.6 km2 (mean ± SE, n = 13) and was similar to home-range estimates reported in other studies conducted within grassland habitats in other portions of the species' geographic range. Male home ranges were larger than those of their mates during pup-rearing periods (P < 0.04) but were similar in size during the dispersal period. The home ranges of both sexes were smallest during the pup-rearing period. The degree of home-range overlap for mates (biological periods combined) was high (range = 27.4–100%, mean ± SE = 70.8 ± 0.03%, n = 26 pairs) but was minimal between adjacent pairs (range = 0.2–36%, mean ± SE = 11.9 ± 2.4%, n = 10 pairs), suggesting territorial behavior. Occupied home ranges were distributed similarly each year despite one or both pair members often being new. Swift fox home-range size varied seasonally, and home-range dispersion patterns appeared to be influenced by the presence of other fox pairs and the recent use of an area by other swift foxes.


2003 ◽  
Vol 117 (3) ◽  
pp. 424 ◽  
Author(s):  
Patrick R. Lemons ◽  
Warren B. Ballard ◽  
Robert M. Sullivan ◽  
Marsha A. Sovada

Activity of Swift Foxes (Vulpes velox) at den sites was studied in northwestern Texas during pup rearing seasons in 2000 and 2001 to determine role of males in parental care. Twenty-four percent of radio-collared females with a potential to breed successfully raised pups to eight weeks of age. We intensively monitored presence and absence of male and female Swift Foxes at two den sites each year. Females were present >2.6 times more at den sites than males during the pup rearing season. Female and male Swift Foxes largely stayed at dens during diurnal hours and were active away from dens during nocturnal and crepuscular hours. Females and males spent 12.4% and 3.0% more time at dens before pups emerged, than after pups emerged, respectively. Following depredation of one male parent, the female spent 29% less time at the den site. Decrease in time spent at the den by the female following loss of her mate suggested that loss of one parent might severely impact recruitment of Swift Foxes. Our observations indicated that intense Coyote (Canis latrans) depredation may severely impact pup-rearing success as well as the parental care within Swift Fox family groups.


2012 ◽  
Vol 90 (3) ◽  
pp. 337-344 ◽  
Author(s):  
Amariah A. Lebsock ◽  
Christopher L. Burdett ◽  
Safi K. Darden ◽  
Torben Dabelsteen ◽  
Michael F. Antolin ◽  
...  

Space use is a fundamental characteristic that informs our knowledge of social relationships and the degree to which individuals are territorial. Until recently, relatively little was known about the spatial ecology and social organization of swift foxes ( Vulpes velox (Say, 1823)). We investigated space use of swift foxes on shortgrass prairie in northeastern Colorado. Our first objective was to evaluate sizes of seasonal and annual home ranges and core areas of 13 radio-collared swift foxes monitored continuously for 2 years. Our second objective was to compare home-range and core-area overlap of breeding pairs to that of neighboring foxes, including male–male, female–female, and nonbreeding female–male dyads. Home-range size in our study population was among the smallest previously reported for swift foxes. Males tended to have slightly larger home ranges and core areas than females, and home-range size was significantly larger in the breeding season than in both the pup-rearing and the dispersal seasons; sizes of core areas did not differ seasonally. Spatial overlap between breeding pairs was substantial, whereas spatial overlap between neighbors, particularly males, was low, suggesting territoriality.


2007 ◽  
Vol 121 (1) ◽  
pp. 71
Author(s):  
Brady K. McGee ◽  
Warren B. Ballard ◽  
Kerry L. Nicholson

Predator avoidance may be a reason why Swift Foxes (Vulpes velox) are one of the most burrow-dependent canids in North America. Typically Swift Foxes have multiple dens, which they frequently move among. As part of a larger study to reduce Coyote (Canis latrans) related mortalities on Swift Foxes, we installed artificial escape dens in areas occupied by Swift Foxes on Rita Blanca National Grassland, Dallam County, Texas. For this paper, our objective was to determine the effects of artificial escape dens on Swift Fox den use patterns. From January 2002 to August 2004 we captured, radio-collared, and monitored 55 Swift Foxes. We documented annual number of dens used, rate of den use (fidelity), distance between dens, den area, and den sharing. We compared treated (artificial dens installed) and untreated (no artificial dens) areas but found no differences in annual number of dens (P = 0.64; mean = 8), rate of den use (P = 0.96; mean = 35%), mean distance between dens (P = 0.99; mean = 2,311 m), den area (P = 0.55; mean = 5.72 km2), or den sharing (P = 0.46; mean = 42% of time). We did not observe an effect of artificial escape dens on Swift Fox den use patterns probably because artificial escape dens were designed for temporary escape cover rather than diurnal den use.


2000 ◽  
Vol 78 (12) ◽  
pp. 2106-2111 ◽  
Author(s):  
Jan F Kamler ◽  
Philip S Gipson

We radio-tracked 10 coyotes (Canis latrans) from April 1996 to March 1998 on Fort Riley Military Reservation, Kansas, to compare movements, habitat use, and survival between resident (breeders and pack associates) and transient coyotes. Home ranges of resident coyotes were mutually exclusive, whereas those of transient coyotes overlapped the home ranges of other coyotes. Excursions from home ranges were made by all resident pack associates but not by resident breeders. Grassland habitats were used more than expected by resident coyotes but less than expected by transients. Woodlands and cultivated lands were used more than expected by transients. Transient coyotes used areas between the home ranges of resident family groups. Annual survival rates were higher for resident than for transient coyotes. Avoidance of resident coyotes by transient coyotes may explain differences in space and habitat use by coyotes.


2006 ◽  
Vol 120 (1) ◽  
pp. 31 ◽  
Author(s):  
Ann M. Kitchen ◽  
Eric M. Gese ◽  
Sarah G. Lupis

Predation by Coyotes (Canis latrans) is a major source of mortality in Swift Fox (Vulpes velox) populations. Year-round den use by Swift Foxes is likely to be a predator avoidance strategy. Due to the importance of denning to Swift Fox ecology, we recorded den site selection of Swift Foxes in southeastern Colorado. Den site selection was recorded at two scales: microhabitat characteristics at the den and den placement within the home range. The number of den entrances, height and width of each entrance, aspect, hill position, slope, percent rock in soil, vegetative cover, and horizontal foliar density of 42 Swift Fox dens were examined during December 1999 – April 2000. This was compared to the same microhabitat characteristics at 42 random sites within Swift Fox home ranges to determine if Swift Foxes were using site characteristics according to their availability. Our results indicated that Swift Foxes were not highly selective of den sites based on the microhabitat characteristics evaluated in this study, although Swift Foxes selected areas of intermediate rock percentages. In addition, Swift Foxes were radio-tracked throughout the sample period and the location and frequency of use of known dens were recorded. Within the core area of home ranges, Swift Foxes used more dens (mean = 3.51 ± 1.70 (SD)), and had a higher frequency of use of dens (mean = 8.20 ± 6.01) than in the mid-range area (number of dens, mean = 0.90 ± 0.94; frequency, mean = 1.27 ± 2.12) and the boundary area (number of dens, mean = 0.34 ± 0.53; frequency, mean = 0.45 ± 0.93) of the home range. We discuss our results in terms of the importance of dens in facilitating escape from Coyotes. These results illustrate the need for examining den site selection at multiple scales to determine all selection factors, and to provide information useful for recovery and management efforts for this species.


1999 ◽  
Vol 77 (10) ◽  
pp. 1645-1656 ◽  
Author(s):  
Ann M Kitchen ◽  
Eric M Gese ◽  
Edward R Schauster

In its current distribution and abundance, the swift fox (Vulpes velox) has been significantly reduced from its historic range. A possible cause is competition with, and predation by, coyotes (Canis latrans). We investigated the level of spatial, temporal, and dietary resource use overlap between swift foxes and coyotes at the Pinon Canyon Maneuver Site in southeastern Colorado. We captured and radio-tracked 73 foxes and 24 coyotes from April 1997 to August 1998. We collected 10 832 and 5350 locations of foxes and coyotes, respectively. Overall, home-range sizes of foxes and coyotes were 7.6 ± 0.5 (mean ± SE) and 19.8 ± 1.9 km2, respectively. A high degree of interspecies spatial overlap was apparent, with fox home ranges being overlapped by coyote home ranges by as much as 100% and coyote sign (tracks and scats) being evident in all swift fox home ranges. There was no evidence of temporal avoidance of coyotes in fox movement patterns. Coyotes traveled significantly farther than foxes during diurnal hours; foxes spent the majority of diurnal hours in or on top of dens. Coyotes and foxes showed a high index of overlap for dietary resources, although some dietary partitioning was apparent. Swift foxes specialized in small prey, such as insects and rodents, while coyotes used greater proportions of large prey, such as lagomorphs and ungulates. Interference competition was evident, with 48% (12/25) of fox mortalities identified as confirmed or probable coyote-caused deaths. In each case, death occurred outside either the fox's home range or the 85% isopleth of that range, indicating that coyotes are more likely to attack a fox successfully when it is a substantial distance from a den. We propose that swift foxes are able to coexist with coyotes, owing to year-round den use and a degree of dietary partitioning.


2001 ◽  
Vol 28 (3) ◽  
pp. 214 ◽  
Author(s):  
Jennifer Koenig ◽  
Richard Shine ◽  
Glenn Shea

Although most species of large reptiles in the Sydney region are now restricted to remnant bushland, the blue-tongued lizard (Tiliqua scincoides) remains abundant. How has this large, slow-moving reptile managed to persist in the suburbs? We implanted radio-transmitters into 17 adult blue-tongued lizards and tracked them for six months (October 1998 to March 1999). Radio-tracked animals utilised 5–17 suburban backyards, but each lizard spent most of its time in a few ‘core’ areas near 2–7 shelter sites. Males had larger home ranges than females (mean of 12700 v. 5100 m 2 ) and moved further between shelter sites. Gravid females (mean home range 1000 m 2 ) were more sedentary. Lizards used corridors of dense vegetation to move between retreat sites, and actively avoided crossing roads. In sunny weather, lizards typically basked close to their overnight shelter for 1–4 h each morning until they obtained body temperatures of approximately 32°C. They maintained high body temperatures while moving about in the afternoon. In combination, the following ecological factors may facilitate persistence of blue-tongued lizards at our suburban study sites. (i) The most important subgroup of the population in terms of conservation are gravid females, which are highly sedentary and, thus, less likely to encounter the dangers of suburbia. (ii) The more ‘expendable’ males move about much more, but mostly in times and places that involve minimal risk from humans and their domestic pets. (iii) Lizards show strong site fidelity, spending up to 70% of their time in ‘safe’ locations; importantly, they avoid roads. (iv) Blue-tongued lizards readily utilise ‘artificial’ shelter sites and the commensal prey species (e.g. snails) found in most gardens. (v) These lizards can grow rapidly, mature early, and produce large litters. Because blue-tongued lizards have a long life span (over 30 years in captivity), populations of adults may persist for many years in the absence of recruitment.


2012 ◽  
Vol 57 (4) ◽  
pp. 393-398 ◽  
Author(s):  
Donelle L. Schwalm ◽  
Warren B. Ballard ◽  
Ernest B. Fish ◽  
Heather A. Whitlaw
Keyword(s):  

1994 ◽  
Vol 21 (1) ◽  
pp. 65 ◽  
Author(s):  
A Horsup

The home range and movements of the allied rock wallaby, Petrogale assimilis, a small macropod of the seasonally wet-dry tropics of Queensland, were studied over a 22-month period. There was no significant difference in the size of home ranges (95% isopleth) or core areas (65% isopleth) of males and females. Home ranges were generally elliptical with a mean size of 11.9 ha. Season had a major effect on home ranges. The following measures were all significantly greater in the dry seasons than in the wet seasons: home-range size (larger), home-range shape (more elongate), distance moved by females when feeding (longer), distance between shelter site and home-range centre of activity (longer). Feeding movements of males did not vary seasonally and were as long as dry-season movements of females, suggesting that movements of males are primarily determined by behavioural rather than physiological considerations. The overlap of rock-wallaby home ranges varied little between the sexes or seasons and averaged 38%. Core areas overlapped by an average of 22%; however, feeding adult rock-wallabies rarely met other conspecifics, except their partners. A comparison of the fixes of unpaired wallabies that had overlapping home ranges showed that temporal separation was occurring. In contrast, the home ranges of consort pairs showed extremely high temporal and spatial overlap. Rock-wallabies exhibited strong fidelity to their home ranges. The overlap of the seasonal home ranges and core areas of each individual rock wallaby averaged 68% and 52%, respectively. However, the seasonal home range of a socially immature adult male altered in location and size as he matured socially until it stabilised when he obtained a permanent consort.


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