Early winter food habits of white-tailed deer in southern Michigan

Master of ScienceWildlife ManagementUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/101285/1/39015003286542.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/101285/2/39015003286542.pd

Seasonal variation in California bighorn ram (Ovis canadensis californiana) habitat use and group size

Seasonal changes in bighorn sheep (Ovis canadensis) habitat use and social systems can create profound management challenges. We studied spring-summer distribution, habitat use, and group size of California bighorn rams on Poker Jim Ridge, Oregon. Ram groups were observed during April-August 1990. Herd range was smaller in spring (24.4 km2) than summer (74.5 km2). Ram groups were closer to escape terrain (P< 0.001), farther from water (P < 0.001), on gentler slopes (P = 0.01) and at higher elevations (P < 0.001) in spring. Distance to escape terrain and distance to water were significant main effects differentiating spring and summer habitat use (P < 0.001). Rain group size varied by month (P < 0.001), with groups in July-August smaller than those in April-June (P < 0.01). Seasonal changes in ram distribution appeared to be associated with changing habitat conditions, particularly water availability. Small group sizes in late summer probably reflected resource limitations, and occurred in spite of use of less secure habitats during this period. Managers of bighorn sheep populations should consider the unique requirements of their populations under a variety of environmental conditions, and provide adequate protection to sustain seasonal shifts in distributionPayer and Coblentz "Seasonal variation in California bighorn ram (Ovis canadensis californiana) habitat use and group size." Northwest Science. 1997; 71(4): 281-28

Development of a prolonged estrus effect for use in Judas goats

The use of Judas goats (JGs; Capra hircus) to locate remnant animals is a powerful tool for enhancing feral goat eradication efforts, being especially important to island conservation programs. JGs are goats that are captured, fitted with radio telemetry collars and released. As goats are gregarious, JGs search out and associate with other goats. They can then be tracked down and any associated feral goats removed. JGs increase the efficiency of removing animals at low densities by reducing search time for hunters locating remnant herds. Prolonged duration or increased frequency of estrus in female JGs could potentially increase the efficiency of this method; does in estrus actively seek out and are searched for by bucks, and are more active than non-estrus does. Two experiments under controlled, farm conditions demonstrated that estrus can be prolonged by using Compudose-100 implants (one or two implants; single dose 21.1 mg estradiol 17β) or a single Synovex-S implant (200 mg progesterone and 20 mg estradiol benzoate). Two Synovex-S implants failed to significantly prolong estrus. Single Compudose-100 implants provided the most dramatic effect, and when combined with 15 mg PGF2∝ and sterilization by tubal occlusion provides an effective means of terminating pregnancy, inducing sterility and prolonging estrus 6–16-fold compared to sterile does and at least 82-fold compared to unaltered does, with a single intervention. Incorporating these methods into Judas goat programs will likely increase the efficiency and capability of feral goat control and island conservation

Increasing the efficacy of Judas goats by sterilisation and pregnancy termination

The use of Judas goats to locate remnant animals is a potentially powerful tool for enhancing goat-eradication efforts, which are especially important to island conservation. However, current Judas goat methodology falls short of its potential efficacy. Female Judas goats are often pregnant at the time of deployment or become impregnated in the field; pregnant females leave associated goats to give birth, causing downtime of Judas goat operations. Further, male Judas goats may inseminate remnant females. Sterilising Judas goats prior to deployment removes these inefficiencies. Here, we describe two methods (epididymectomy for males and tubal occlusion for females) that sterilise Judas goats while still maintaining sexual motivation and other behaviours associated with intact animals. These surgeries are straightforward, time efficient, and may be conducted in the field by staff with minimal training. Given the widespread and deleterious impacts of non-native herbivores to ecosystems and the importance of Judas operations in detecting animals at low densities, sterilisation and termination of pregnancy should be applied routinely in Judas goat (and possibly other species) programs to increase the efficacy of low-density control operations and eradication campaigns