Anthony J. DeNicola

Effects of Parturition on Home Ranges and Social Affiliations of Female White-Tailed Deer

The effects of parturition, contraceptive treatment, and a buck harvest on home range sizes and social affiliations of 48 female white-tailed deer (Odocoileus virginianus) were studied in a 176-ha enclosure in southern Connecticut. Population density was reduced from 68 deer/km 2 to 39 deer/km 2 in late 1992 through removal of 51 bucks. The male: female sex ratio changed from 3:2 to 1:2. Concurrently, 24 does were treated with experimental contraceptives. Kernel home ranges enclosing 95 and 50% of each does utilization distribution were calculated for 2 6-week periods following parturition in 1992 (pre-harvest), and 4 6-week periods in 1993 (post-harvest): 1 period before and 3 periods following parturition. Mean home range size and frequency of association with other does were significantly greater following the harvest. Lactating does occupied smaller home ranges than non-lactating does only in the post-harvest year. Lactating does associated with other does less frequently than did non-lactating does in all periods and both years. Frequency of association was lowest during the first 6 weeks following parturition. The proportion of significant social interactions between pairs of does did not change between years. Contraceptive treatment had no effect on home range size, but led to a lower frequency of social affiliations. Our results indicate parturition led to smaller home ranges and lowered sociability among does with fawns for 6 weeks pre-partum and 12-18 weeks postpartum in the post-harvest year, but these effects were partly masked in the pre-harvest year, when population density was highest.

Reduced abundance of Ixodes scapularis (Acari: Ixodidae) and the tick parasitoid Ixodiphagus hookeri (Hymenoptera: Encyrtidae) with reduction of white-tailed deer.

Abstract The principal vector for the pathogens of Lyme disease, human granulocytic ehrlichiosis, and human babesiosis is the tick Ixodes scapularis Say. A chalcid wasp, Ixodiphagus hookeri, in the family Encyrtidae parasitizes populations of the tick on several islands or other geographically isolated sites in New England with high densities of these ticks and white-tailed deer (Odocoileus virginianus), the principal host for adult I. scapularis. Deer densities were reduced at a forested tract in Bridgeport and the Bluff Point Coastal Reserve in Groton, Connecticut, from levels exceeding 90 animals per km2 in 1992 (Bridgeport) and 1994 (Bluff Point) to 17 and 10 animals per km2, respectively, by fall 2001. Tick densities declined with sustained reductions in the population of white-tailed deer. Similarly, prevalence of tick parasitism by Ixodes hookeri declined at both sites from 30 to 25% to <1.0% and was significantly correlated with previous year’s deer density at both sites (rs = 0.933 and rs = 0.867, P ≤ 0.0001) and with nymphal tick densities at Bridgeport (rs = 0.867, P ≤ 0.0001), but was not as well correlated with tick densities in Groton. The virtual disappearance of I. hookeri in this study corresponds with a lack of I. hookeri in mainland I. scapularis at comparable deer and tick densities, suggesting that there is a threshold deer density of ≈10–20/km2, with corresponding tick densities necessary for I. hookeri to successfully parasitize I. scapularis.

Topical Treatment of White-Tailed Deer with an Acaricide for the Control of Ixodes scapularis (Acari: Ixodidae) in a Connecticut Lyme Borreliosis Hyperendemic Community

The 4-Poster device for the topical treatment of white-tailed deer, Odocoileus virginianus (Zimmermann), against ticks using the acaricide amitraz, was evaluated in a Lyme borreliosis endemic community in Connecticut. As part of a 5-year project from 1997 to 2002, 21-24 of the 4-Posters were distributed at residential sites in Old Lyme, CT, in a core treatment area of approximately 5.2 km(2) in fall 1997. The 4-Posters were active October to mid-December and March into May, corresponding to the peak periods of activity for adult Ixodes scapularis in this particular area. Corn consumption ranged from 361 to 4789 kg/month for October and November and 696-3130 kg/month during April. Usage of 4-Posters by deer generally was high (>90%), except during acorn masts in fall 1998 and 2001. Amitraz was applied by rollers at the estimated rate of 1.3 g active ingredient/ha/year. The abundance of host-seeking I. scapularis nymphs declined significantly (p < 0.001) in the core treatment area, as compared to a control community in Old Saybrook, CT, through 2004, over the project period from 1998 to 2003, from 9.3/100m(2) to 0.97/100m(2), rising to 1.90/100m(2) in 2004. From 1999 through 2003, there were 46.1%, 49.6%, 63.4%, 64.6%, and 70.2% reductions, respectively, in the nymphal tick population in comparison with the untreated community and initial tick abundance in 1998. Control of I. scapularis adults declined to only 19.1% in 2004; 2 years after the treatment of deer was discontinued. Differences in nymphal tick abundance between the control and core treatment area were significant in 1999 (p = 0.042) and highly significant in 2001 (p < 0.001) and 2002 (p = 0.002). The passive topical application to deer of the acaricide amitraz resulted in a significant decrease in the population of free-living I. scapularis nymphs in the treated core in Connecticut.

Dose determination and efficacy of remotely delivered norgestomet implants on contraception of white-tailed deer

Management of overabundant wildlife populations using contraceptives is being considered with increasing frequency in many localities. A wide array of effective contraceptives is needed to meet a variety of management objectives. Therefore, we evaluated the synthetic progestin norgestomet for its efficacy and its minimum effective dose in free-ranging white-tailed deer (Odocoileus virginianus). We evaluated two doses of norgestomet implants (14 and 42 mg) at a site in southern Connecticut during 1992–1995. Four doses (14, 21, 28, 42 mg) of norgestomet implants were tested at a site in northern Indiana during 1993–1996. The effectiveness of norgestomet implants in preventing pregnancy was similar for the 42 mg (92%), 28 mg (100%), and 21 mg (100%) doses. There was a significant decline in efficacy using the 14 mg (48%) dose. It appears that 21 mg is approximately the lowest dose that consistently prevents reproduction in adult white-tailed deer of various sizes and ages. Norgestomet implants show promise as a highly effective contraceptive agent that is safe to treated animals and secondary consumers and simple to deliver remotely. Zoo Biol 16:31–37, 1997.

Acaricidal treatment of white-tailed deer to control Ixodes scapularis (Acari: Ixodidae) in a New York Lyme disease-endemic community.

The efficacy of topically treating white-tailed deer with an acaricide was evaluated in a Lyme disease-endemic community of southern New York State. Twenty-four 4-Poster feeders were placed in a 5.2 km(2) treatment area in Bedford, NY, while a site in Lewisboro, NY, 4.8 km distant, served as control. Treatment periods ran from 15 September to 15 December each fall from 1997 to 2001, and from 15 March to 15 May each spring from 1998 to 2002. Corn consumption averaged 15,779 kg in fall sessions and 9054 kg in spring sessions, and a mean of 89.6% of deer in the study area showed evidence of using the feeders. Deer densities, estimated by aerial snow counts, averaged 22 and 28 deer per km(2) in Bedford and Lewisboro, respectively, over a 3-year period. Significant reductions in tick numbers on deer captured in the treatment area were noted in fall 1999 compared to deer captured at the control site. Drag sampling for nymphal host-seeking ticks indicated 63.6% control in 2001, which dropped to 54.8% the following year, but reached 80% in 2003. Higher-than-normal acorn production in 2001 that likely caused a drop in deer visitation to the feeders may have reduced efficacy against larval ticks in 2002. The 4-Poster effectively reduced the density of Ixodes scapularis, though the level of control is dependent on environmental factors that affect feeding behavior of white-tailed deer.

Successful field capture techniques for free‐ranging argali sheep (Ovis ammon) in Mongolia

Argali sheep (Ovis ammon) are the worlds largest wild sheep and are threatened throughout their range in Mongolia. Little is known about the ecology of this highly cursorial species. This project was initiated to develop safe capture techniques in order to learn more about the ecology of argali in the Ikh Nartiin Chuluun Nature Reserve in southeastern Mongolia by using radiotelemetry. To our knowledge no one had ever successfully live-caught a free-ranging argali. We developed three techniques for capturing argali. From 2003 to 2007 we hand captured 65 argali lambs, losing one (our first capture) to maternal neglect because we stayed too long in the area and a second that was euthanized after being accidentally injured by a horse. Between 2000 and 2003 we captured six argali by darting, losing one ewe to an abdominal infection after a misplaced dart. Finally, between 2002 and 2007 we captured 32 argali by drive-netting. We lost one ewe to over-exertion after a long drive. The remaining 31 animals captured by drive-netting did not appear to suffer any immediate effects (still alive in 30 days). This report will discuss the strengths and weaknesses for each of these capture techniques. Zoo Biol 27:137-144, 2008. (c) 2008 Wiley-Liss, Inc.

Argali lamb (Ovis ammon) morphometric measurements and survivorship in Mongolia.

Abstract We examined variables that might affect survivorship of neonatal argali sheep (Ovis ammon), including body weight, date of birth, gender, precipitation, and year affects, which often influence neonatal survivorship in other species of sheep. From 2003 to 2008 we hand-captured 75 argali lambs (38♂, 36♀, 1 undetermined) and attached expandable, drop-off radio collars in Ikh Nart Nature Reserve, Mongolia. We collected morphometric and physiological measurements and radio-tracked lambs to obtain data on survivorship and mortality. We found similar morphometric and physiological measurements for male and female lambs, with significant differences only in foreleg length (♀<♂) and respiration rates (♀>♂). Only 44.6% of argali lambs survive their first month of life, but thereafter their mortality rate decreases. Lambs not born in 2006, born in years following years with higher April precipitation, and born later in the year enjoyed significantly higher survival to one month. We found high mortality in the years with severe drought (2005–2006), which depressed overall survivorship. We found no significant effect of any physiological or morphometric variables on lamb survival. Argali lambs die from several causes, with predation (44.6%) and starvation (21.4%) being the most significant.

The Effect of Remotely Delivered Gonadotropin Formulations on Reproductive Function of White-Tailed Deer

AbstractThree experiments were conducted on two white-tailed deer herds over 2 years. In the first year, 8 of 17 does were remotely treated with a human chorionic gonadotropin-ovalbumin/saponin (hCG) biobullet formulation. In the second year, 11 of 23 does from one herd and 10 of 35 does from the second herd were remotely treated with porcine luteinizing hormone (pLH) biobullet formulation. Treatments were administered from September to mid-October, before the breeding season. Reproduction was assessed the subsequent spring. All untreated and hCG-treated does gave birth and timing of the parturitions was unaffected by the hCG treatment. In the second year, more (p<0.05) pLH-treated does than untreated does gave birth at the first location. In addition, a higher number of the pLH-treated deer gave birth earlier the next spring at the first location. Therefore, remote treatment with a sustained-released pLH biobullet formulation may enhance reproductive function of white-tailed deer.