Réale et al. (2000) states that, \"Although humans have modified the rutting and lambing seasons of O. aries, some feral populations show highly synchronized estrus and lambing periods that relate to latitude (Jewell 1989 ). These herds were assumed to have recovered that synchrony because of the high adaptive value of spring lambing.\"

Grazing and browzing of herbaceous vegetation, and stripping of bark by feral sheep and other introduced mammals (cattle (Bos taurus), Mouflon sheep (Ovis musimon), and feral goats (Capra hircus)) have led to exposure of soil to erosion and degradation of forests on Mauna Kea (Scowcraft and Sakai 1983). Welsh (2002) adds that, \"O. aries are extensive and destructive herbivores. They have been found to decrease populations of the mamane (Sophora chrysophylla), an endemic leguminous tree, by stripping the bark off thus facilitating damage from insects and and other disease causing organisms\". Results of a study (Scowcroft and Giffen 1983) which evaluated the regeneration of vegetation and forests inside and outside sheep exclosures located in heavily browsed portions of the mamane forest of Mauna Kea, indicated feral sheep browsing suppresses regeneration of mamane and three other endemic species, Hawai‘ian bent, heu-pueo, and aheahea.

Liu and Jiang (2004) report that, \"The most important food competitor of the critically endangered Przewalski's gazelle (see Procapra przewalskii in IUCN Red List of Threatened Species) is the domestic Tibetan sheep (O. aries) in the steppe and deserts around Qinghai Lake on the Qinghai-Tibet Plateau.\"

Kirby et al. (2004) state that, \"The sheep tick Ixodes ricinus (L.) is an ectoparasite of major economic and pathogenic importance in Scotland. Its distribution in the Scottish uplands is assumed to be governed by the abundance and distribution of its definitive hosts (deer and O. aries) and climatic variables such as temperature and rainfall.

Physical: Management strategies for sheep (O. aries) include hunting and the use of fencing to keep animals out (Welsh, 2002). Due to the behavioural similarities between sheep and goats (see Capra hircus), management strategies and hunting techniques for goats work equally well for sheep, although some minor variations may be required for each technique (this is also the case with goats, depending on vegetation, terrain, naivety). Please see Campbell & Donlan, 2005; Parkes et al. 1996 and Daly & Goriup, 1987 for more details on management strategies and hunting techniques for goats. Trapping of sheep at waterpoints or other limited resources (e.g. salt licks in some areas) can be highly effective. Please see O'Dempsey, 1993 for methods.

The use of Judas sheep as a hunting method could be applied quite easily; sheep are highly social animals and will search for conspecifics when isolated. Techniques like sterilisation, termination of pregnancy and inducing a prolonged estrus in goats for increasing their efficacy as Judas goats could be adapted for sheep. Epididymectomy can be conducted efficiently in rams with the procedures indicted for male goats. Tubal occlusion could similarly be applied in ewes as described for does. Pregnancy termination in the ewe isn't as straight-forward as it is in goats. In the first 55 days of pregnancy, abortion can be induced with prostaglandins (6 mg PGF2alpha / 58kg body weight), after 55 days pregnancy termination with prostglandins is unlikely (Stellflug et al. 1997). Incorporating cesarean section with sterilisation procedures may be the most effective means of ensuring pregnancy is terminated prior to deployment of Judas sheep. The procedure for cesarean section on sheep is outlined by Mobini et al. 2002.
(Karl Campbell., pers.comm., September 2005).