Mickey Hellickson

1. Patterns of male reproductive allocation provide insight into life-history characteristics. The trade-offs associated with resource and female group defense are well-defined. However, less is understood about trade-offs in species that practice scramble-competition polygyny, where successful strategies may favor competitive mate-searching rather than contest competition and fighting. 2. White-tailed deer (Odocoileus virginianus) practice scramble-competition polygyny where solitary males search for and assess receptivity of females scattered across the landscape. Physically mature males are expected to do most of the breeding because of the high energetic costs of reproduction and high social status. However, young males may collectively sire one-third of offspring. To gain a better understanding of trade-offs associated with scramble-competition polygyny, we quantified metrics associated with reproductive effort and success. 3. We quantified changes in body mass of harvested males, energetic costs of locomotion based on movements of GPS radio-collared males, and timing of reproduction via temporal genetic parentage assignments. 4. Young males (1.5 and 2.5 years old) sired offspring, but their mating success was mainly limited to peak rut, when most females were in estrus. Furthermore, multiple paternity was common, indicating opportunistic reproduction. Reproductive effort, indexed by body mass loss, was highest in prime-age males (5.5-6.5 years old). Surprisingly, young and post-prime males also exhibited significant body mass loss, indicative of investment in reproductive effort. Movement rates increased 2 to 4-fold during rut as a function of mate-search activities, but cost of locomotion would cause only about one-third of observed body mass loss. Because males are capital breeders, we infer most of body mass loss is due to reduced foraging. 5. In scramble-competition polygyny, the repeated location of potential mates and assessment of their estrous status appear to be important constituents of male mating strategies. Therefore mating success may be influenced by time management and spatial memory, and not based solely on social dominance. Thus, reproductive effort should be greater for individuals capable of reducing time foraging. For those that cannot, opportunistic mating opportunities may arise when operative adult sex ratios are low. Our analyses reveal valuable insight into the trade-offs associated with scramble-competition polygyny

Nutrient intake of deer in south Texas is lowest in late summer and winter; therefore, supplemental food may be provided during these times by managers. When natural food resources become scarce, white-tailed deer (Odocoileus virginianus) may shift home ranges or core areas to incorporate supplemental food sources. Thus, supplemental food sources may influence daily movements and home range characteristics of deer. To examine how deer were distributed relative to supplemental feed sites, 48 adult male white-tailed deer were radio collared and tracked from October 2002 to August 2004. The average density of supplemental feeders within deer home ranges was 47 % lower in year 1 and 18 % lower in year 2, than the density of feeders in the study area (>0.19 supplemental feeders/mile). Home ranges of deer with feed (n = 17, 635.6 ± 64.5 acres) were larger (t25 = 3.44, P = 0.002) than deer home ranges without feed (n = 14, 379.8 ± 37.1 acres). In both years, there was no difference amon...

Predictive equations based on various body measurements have provided managers with practical and reliable estimates of mass, but have not been reported for white-tailed deer (Odocoileus virginianus) in the Western Rio Grande Plains region of Texas, nor for male white-tailed deer in Texas. To address this need, we assessed relationships among live and dressed mass, chest girth, shoulder height, front hoof length and width, and gross Boone and Crockett Club (BCC) score. Regression analyses indicated live mass of mature (>5.5 years old) males can be predicted based on dressed mass (R = 0.883). Live mass for fawn and yearling females can be predicted with models based on dressed mass (R = 0.962), front hoof length (R = 0.898), shoulder height (R = 0.822) and chest girth (R = 0.772); while dressed mass (R = 0.818) provided the best prediction of live mass for adult (>2.5 years old) females. However, alternative variables other than dressed mass are needed for live-captured deer th...

Nutrient intake of deer in south Texas is lowest in late summer and winter; therefore, supplemental food may be provided during these times by managers. When natural food resources become scarce, white-tailed deer (Odocoileus virginianus) may shift home ranges or core areas to incorporate supplemental food sources. Thus, supplemental food sources may influence daily movements and home range characteristics of deer. To examine how deer were distributed relative to supplemental feed sites, 48 adult male white-tailed deer were radio collared and tracked from October 2002 to August 2004. The average density of supplemental feeders within deer home ranges was 47% lower in year 1 and 18% lower in year 2, than the density of feeders in the study area (>0.19 supplemental feeders/mile²). Home ranges of deer with feed (n = 17, 635.6 ± 64.5 acres) were larger (t25 = 3.44, P = 0.002) than deer home ranges without feed (n = 14, 379.8 ± 37.1 acres). In both years, there was no difference among...

In south Texas, white-tailed deer (Odocoileus virginianus) translocations have become a common technique for non-lethal means of deer re- moval with the implementation of a Trap, Transport, and Transplant (TTT) permit program. However, the effectiveness of TTT as a management tool has not been evaluated. We monitored survival, movements, and body condition of 51 adult white-tailed deer from two translocations to two 2,000-ha south Texas properties, one of which was partially enclosed by a 2.5-m net-wire fence. Annual survival of all translocated deer was lower in the partially fenced property (64%) compared to the unfenced property (80%), but overall survival was similar to survival rates of adult native south Texas deer reported in previous studies (68%-74%). As expected, more deer left the unfenced property (52%) than the partially enclosed property (14%). Cumu - latively, 40% of deer survived and remained on the release area after one year. Young (1.5-3.5 years old) translocated ...

Background/Question/Methods Forage availability and nutritional quality are commonly driving factors in habitat selection by Cervids. However, thermal cover has been implicated to influence habitat selection in subtropical and semiarid climates with hot summers. We hypothesized that habitat selection by male white-tailed deer (Odocoileus virginianus) during midday in summer is driven by availability of sites with low operative temperatures and taller woody canopy height rather than screening cover, forage crude protein, and forage standing crop. Operative temperatures were estimated using blackglobes that were constructed using 15cm diameter copper balls. Fifty one blackglobes with temperature sensors were randomly placed within 10 vegetation communities throughout the 1,367 ha study site and recorded temperatures every 30 minutes. Six male white-tailed deer were captured in autumn 2007 and 8 male white-tailed deer were captured during autumn 2008. All deer were fitted with Lotek 33...

ABSTRACT The relationship of antler size at one age to that at a later age is important in cervid management, in part by defining the effects of selective harvest based on antler characteristics. We used capture and harvest records from 2,948 male white-tailed deer (Odocoileus virginianus) on 5 study sites over a 10-year period to define age-antler size relationships. Antler size (Boone and Crockett score converted to cm) increased with deer age to 5 years of age, and we therefore considered males mature at ≥5 years of age. Antler size at ≥2 years of age was positively related to yearling antler size with antler size increasing 0.64 cm (SE = 0.07) for every cm of yearling antler score. Antler size at maturity increased 0.52–0.78 cm (SE = 0.05–0.12) for each cm of antler size at 2, 3, and 4 years of age. Number of yearling antler points is a criterion in some selective harvest regimes. Yearling deer with ≤3 antler points had antlers at maturity that were 32 cm (SE = 8.4 cm) smaller than deer with ≥4 antler points as yearlings. Because of a relationship between yearling antler size and antler size at later ages, selective harvest at young ages can influence antler size of deer remaining in the cohort at later ages. © 2014 The Wildlife Society.

ABSTRACT Thermal cover may influence habitat selection by white-tailed deer Odocoileus virginianus in subtropical climates with hot summers. We 1) tested the hypothesis that thermal environment is more important in habitat selection at midday during summer than forage quality or quantity and concealment cover and 2) determined whether operative temperature, vegetation height, or woody plant canopy cover (or some combination of these) explain habitat selection at midday. We predicted that during crepuscular periods and at night habitat use increases with increasing forage quality and quantity and concealment cover and is unrelated to thermal environment. Male white-tailed deer were fitted with GPS collars to determine resources selected within habitats during June and July 2008 and 2009. A generalized linear mixed model using logistic regression was used to estimate resource selection functions. We used the first principal component in a principal components analysis (PCA) of forage standing crop, crude protein, and acid detergent fiber (ADF) to create a 'forage index'. This index and vegetation height, operative temperature and concealment cover, together with their interactions with activity period, were used to develop a priori candidate models. Akaike weights were used to compare candidate models. A model that included the forage index, vegetation height, operative temperature, concealment cover and their interactions with activity period was the best model out of 97 candidate models for explaining habitat selection by adult male white-tailed deer. Male white-tailed deer selected areas with taller vegetation in morning and midday activity periods but selected shorter vegetation during evening and nighttime. Forage quality was important in habitat selection in all activity periods. Male white-tailed deer did not select areas with greater concealment cover during any activity period. A combination of operative temperature, vegetation height, and woody plant canopy cover predicted midday habitat use better than any of these three variables alone. Thermoregulatory behavior in male white-tailed appears to include a combination of seeking cooler environments during midday but at the same time using areas with greater forage quality.

Abstract We used genetic-based paternity assignments from 3 diverse populations of white-tailed deer (Odocoileus virginianus) to evaluate the long-held assumption that male reproductive success in this species is highly skewed toward a small number of mature, ...