Mark C. Wallace

Toe Clipping of Amphibians and Reptiles: Science, Ethics, and the Law 1

Abstract Public concern for the humane treatment of animals in research has led to specific guidelines for appropriate treatment of study organisms. Field research poses special challenges that Institutional Animal Care and Use Committees find difficult to address based on existing guidelines. Toe clipping is a common but contentious example whose use has been called barbaric and whose efficacy has been questioned. We provide a brief review of the ethical bases for such positions, the legal framework they have engendered, and the scientific evidence regarding the impacts of the practice. Leading philosophical views vary but tend to focus on the suffering or distress of individual animals, primarily vertebrates. The law has adopted this individual-centered view. Biologists, in contrast, tend to more wholistic views that focus on populations and ecosystems. Scientific studies of the impacts of toe clipping, most of them relatively recent, have become increasingly sophisticated statistically. Most show little impact of toe clipping on study animals, the exception being the likelihood of recapture of toe-clipped individuals in some frogs. If unaccounted for, effects of methodology can bias scientific findings. The few studies focusing on physiological indicators of distress show no increase resulting from toe-clipping. Thus, toe clipping of reptiles and amphibians meets legal and ethical expectations and should remain acceptable where it meets study needs. Biologists have long been concerned about the possible ethical implications of their methods. Philosophical inquiry has been beneficial in improving our understanding of these methods, but the need of biologists for better philosophical elaboration of ecological ethics has only partially been addressed.

SURVIVAL OF FEMALE ELK IN NORTHERN ARIZONA

Because modeling and sound management of ungulate populations requires reliable estimates of survival and mortality, we measured survival and cause-specific mortality rates for 43 yearling and 197 adult, radiocollared female elk (Cervus elaphus) in hunted and unhunted areas of northern Arizona during 1985-93, and for 18 adult radiocollared females from the moderately hunted White Mountain Tribal Reservation (1983- 85). Hunting-related causes were the largest source (62%) of adult mortality. Annual survival was highest in the unhunted segment of the population (0.969). Elk survival rates in northern Arizona are representative of an expanding elk population with few limiting factors, and our data provides baseline information for Mexican wolf (Canis lupus baileyi) reintroductions.

Effects of jet aircraft on mountain sheep

Military-designated air spaces have been established above national parks and monuments, wildlife refuges, wilderness areas, and Department of Defense lands. Each of these landscapes is managed differently, which has led to questions of compatibility between military aircraft and wildlife. We determined the influence of F-16 aircraft overflights on mountain sheep (Ovis canadensis nelsoni) from January 1990 to May 1992 in the Desert National Wildlife Refuge, Nevada. We constructed a 320-ha enclosure and calibrated the area for sound pressure levels (i.e., noise) created by F-16 aircraft flying along the ridgeline of the mountains in the enclosure, approximately 125 m above ground level. In May 1990, we placed 12 mountain sheep from the surrounding area in the enclosure and monitored their behavior and use of habitats for 1 year to ensure they were familiar with the area before they were subjected to aircraft overflights. The habitat use and activity of the sheep in the enclosure were similar to free-ranging conspecifics. In May 1991, we instrumented 5 mountain sheep with heart-rate monitors and added them to the enclosure. During May 1991 to May 1992, F-16 aircraft flew over the enclosure 149 times during 3 1-month periods. We recorded heart rate and behavior of sheep 15 min preoverflight, during the overflight, and postoverflight. Heart rate increased above preflight levels in 21 of 149 overflights but returned to preflight levels within 120 sec. When F-16 aircraft flew over the enclosure, the noise levels created did not alter behavior or use of habitat, or increase heart rates to the detriment of the sheep in the enclosure.

Diets of free-ranging mexican gray wolves in arizona and New Mexico

Abstract Systematic diet studies of Mexican gray wolves (Canis lupus baileyi) were not conducted before wolves were extirpated by the late 1960s from the southwestern United States. We collected carnivore scats (n = 1,682) from the Apache and Gila national forests in Arizona and New Mexico, USA, from April 1998 through October 2001 and identified scats to species using traditional field methods, of which 251 were identified as Mexican wolf scats. We found the diet consisted of large-sized food items (92.8% percent frequency of occurrence [PFO]), primarily elk (Cervus elaphus) adults (36.6% PFO) and calves (36.2% PFO). Biomass calculations indicated that Mexican wolves consumed 414 kg of prey as represented by the scats, with elk representing 76.7% of the biomass. When comparing PFO with percent biomass, PFO calculations may have underrepresented larger food items and percent biomass may have overrepresented smaller food items. We compared the diet composition of Mexican wolf scats (n = 251) to the diets reported in previous North American gray wolf (C. lupus) studies (n = 7). The high proportion of elk in Mexican wolf diets in our study area may reflect the low-density, early colonizing stage of the wolf population and elk probably being the most numerous ungulate in our study area. Our results suggested that free-ranging Mexican wolves consumed a higher proportion of large-sized prey than other North American gray wolves. Our results provide baseline diet information for a newly reestablished wolf population.

Evaluation of two techniques for attaching radio transmitters to turkey poults

Abstract We conducted a pen study to evaluate two methods of attaching radio transmitters to Wild Turkey (Meleagris gallopavo) poults. Transmitters (1.8 g) were attached interscapularly to 2-d-old turkeys, either with glue or as implants. Attachment method had no detectable effect on the growth or survival of poults. Transmitter retention differed between the methods. Mean retention times were 27.6 d for glued backpacks and 30.5 d for interscapular implants. Ease of implementation and behavioral differences of birds immediately after application suggest that glued backpacks are preferred in situations where a retention time of 29 d is adequate.

Livestock Grazing, Wildlife Habitat, and Rangeland Values

livestock and wildlife values should be placed within this broader context. Ranchers and conservationists in the West realize that debates over grazing systems and stocking rates are of little consequence if rangelands continue to be lost or fragmented due to subdivision, farming, weed invasion, catastrophic wildfi re, and energy development. However, impacts of domestic grazing that diminish land value via reduced range productivity and wildlife habitat quality can also lead to alternative land uses and habitat conversion. Maintaining the multiple values of western rangelands will require a shift from local to landscape conservation to match the scale of land use change that threatens grazing, rural ways of life, and wildlife habitat. The future of western rangelands is in developing partnerships that help keep sustainable grazing the prevailing land use. Indeed, as rangelands are lost to other land uses, overlapping interests will make conservation partners out of otherwise odd associates—ranchers need open space for grazing and wildlife biologists, managers, and other conservationists want to maintain or enhance the wildlife values on working ranches. In this paper, we review a representative sampling of scientifi c literature to document grazing impacts on wildlife and its habitat to better understand the roles of grazing strategies in wildlife habitat conservation. Further, we explore commonalities between grazing and conservation interests and provide a vision for advancing wildlife and habitat management and conservation.

Observations on Capturing and Aging Deer Fawns

Abstract During a study of fawn mortality of sympatric white-tailed (Odocoileus virginianus) and mule deer (O. hemionus eremicus) in west-central Texas from 2004 to 2006, we made observations that should help deer researchers increase their efficiency of capture of fawns, obtain better estimates of ages of fawns, and obtain more reliable estimates of fawn survival. We experimented with vaginal-implant transmitter designs and found that larger holding wings and antennas protruding <1 cm past the vulva resulted in more successful drops at birth sites. White-tailed fawns moved farther from birth sites than mule deer fawns of similar ages (P = 0.027). Our model predicted that white-tailed and mule deer fawns moved an average of 100 m away from birth sites after 12.5 and 17.5 h postpartum, respectively; outliers may be expected. Compared to previously published models estimating ages of captive fawns from new hoof growth, our model predicted that free-ranging fawns were generally 1.5 weeks older. As others have suggested, abandonment induced by marking was rare, and we suggest methods for monitoring does and fawns that could minimize such occurrences. Behavioral and morphological models that we describe may be species-, site-, and time-specific, and biologists should use caution when extrapolating inferences from captive animal–derived models to free-ranging populations.

Comparison of Mexican Wolf and Coyote Diets in Arizona and New Mexico

Abstract Interactions between wolves (Canis lupus) and coyotes (C. latrans) can have significant impacts on their distribution and abundance. We compared diets of recently translocated Mexican wolves (C. l. baileyi) with diets of resident coyotes in Arizona and New Mexico, USA. We systematically collected scats during 2000 and 2001. Coyote diet was composed mostly of mammalian species, followed by vegetation and insects. Elk (Cervus elaphus) was the most common item in coyote scats. Mexican wolf diet had a higher proportion of large mammals and fewer small mammals than coyote diet; however, elk was also the most common food item in Mexican wolf scats. Our results suggest that Mexican wolf diet was more similar to coyote diet than previously reported, but coyotes had more seasonal variation. Considering results in other areas, we expect that Mexican wolves will have a negative impact on coyotes through direct mortality and possibly competition. Reintroduction of Mexican wolves may have great impacts on communities by changing relationships among other predators and their prey.

Habitat Use by Sympatric Mule and White-Tailed Deer in Texas

Abstract White-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) occur sympatrically across much of the central and western United States, including portions of west Texas. Fluctuations in populations of both species and the potential for interspecific competition indicate a need for information to aid in management of sympatric populations. We evaluated the role of vegetation and topography on habitat use by sympatric deer in west-central Texas using a geographic information system. We captured and radiocollared 50 female mule deer, 53 female white-tailed deer, and 18 males of each species, and we monitored habitat use from February 2000 to August 2002 in west-central Texas. Mule deer primarily used juniper (Juniperus spp.)-dominated habitats and habitats with elevations >870 m. White-tailed deer home ranges primarily occurred in mesquite (Prosopis spp.)-dominated areas at elevations <840 m. However, overlap did occur, because individuals of both species used or avoided specific areas. Males of both species avoided areas with dense vegetation, including those containing permanent water sources, but females of both species selected such areas, particularly during summer fawning. We did not always detect the same differences observed on the smaller core area (50% kernel home range) scale at the larger home range level, indicating that individuals made decisions about habitat use at different spatial scales. Given the differential importance of various vegetation associations to the establishment of core areas of each sex and species, maintenance of a mosaic of vegetation, particularly in lower-elevation areas and in proximity to food and permanent water, is necessary for managers to perpetuate coexistence of both species. Managers should target habitat conditions of overlap areas, particularly in core areas, for determination of potential limiting factors for both species since competition is mostly likely to occur in these areas.

Survival of Rio Grande Wild Turkey chicks

Abstract Knowledge of chick survival rates is required to develop species-specific habitat-survival relationships. We determined pre-flight daily survival of Rio Grande Wild Turkey (Meleagris gallopavo intermedia) chicks from hatching to time of tree roost at four sites in southwestern Kansas and the Texas Rolling Plains, May–August, 2000 and 2001. One-hundred twenty-three chicks from 39 broods were equipped with cyanoacrylate-attached transmitters. The first day of brood tree-roost ranged from 9–16 d after hatching. Chick survival to 16 d of age ranged from 0.11 to 0.67. One-hundred percent of mortalities in 2000 and 70% of mortalities in 2001 for chicks 0–16 d old occurred <10 d after hatching. Survival at two of four sites was higher for 10–16 d-old chicks than 0–9 d-old chicks. Combining different survival periods may cause biased results when examining habitat-survival relationships.