Natal features (e.g. Julian birth date and birth mass) often have fitness consequences and can be influenced by endogenous responses by the mother to seasonal fluctuations in nutritional quality and photoperiodic cues. We sought to further understand the biological and environmental factors that influence the natal features of a polytocous species in an environment with constant nutritional resources and limited seasonal variation. During a 36-year study we assessed the influence of biological factors (maternal age and litter type [i.e., litter size and sexual composition]) and environmental factors (total precipitation and mean maximum temperature during months encompassing conception, the last trimester of gestation, and the entire length of gestation) on Julian birth date and birth mass using linear-mixed effects models. Linear and quadratic functions of maternal age influenced both natal features with earliest Julian birth dates and heaviest birth masses occurring at prime-age and older individuals, which ranged from 5–9 years of age. Litter type influenced Julian birth date and birth mass. Interestingly, environmental factors affected Julian birth date and birth mass even though mothers were continuously allowed access to a high-quality diet. Random effects revealed considerable variation among mothers and years. This study demonstrates that, in long-lived polytocous species, environmental factors may have a greater influence on natal features than previously supposed and the influence from biological factors is also complex. The documented responses to environmental influences provide unique insights into how mammalian seasonal reproductive dynamics may respond to current changes in climate.

Range expansion of feral swine (Sus scrofa) continues to be pervasive in the United States.

Flexibility in gut morphology has fitness consequences in herbivores. To accommodate dietary variation in energy concentration, rumen-reticulum absorptive capacity and organ mass might also covary. We hypothesized that low energy diets result in greater food intake but lower volatile fatty acid concentrations. The consequence would be heavy rumen-reticulum organs and low absorptive capacity. We measured rumen-reticulum organ mass and absorptive capacity in captive white-tailed deer (Odocoileus virginianus Zimmermann, 1780) from central Texas, USA. Deer consumed a pelleted ration, ad libitum, of 1.77 (low) or 2.67 kcal/gm (standard) digestible energy from the time animals were weaned. In December, 4.5- and 5.5-year-old deer were euthanized, the rumen-reticulum was extracted, thoroughly rinsed, wrung out, and weighted. Four, 1 x 3 cm samples were extracted from four regions of the rumen and mucosal surface area was measured. Our surrogate of food intake and mastication intensity was first molar height. Molar height was lower in animals consuming the low energy diet. Analyses indicated sex-specific responses. Males eating the low energy diet had heavier rumen-reticulum organs but females did not. Females consuming the low energy diet had lower SEF but males did not. The processes driving variation in rumen-reticulum morphology from dietary variation require further examination.

We examined dietary preferences of wild pigs to discern possible bait alternatives to corn. Captive trials were conducted during spring and fall 2021 in the Wild Pig Research Facility at Kerr Wildlife Management Area, Hunt, Texas, USA. We conducted 2‐choice tests by allowing wild pigs to feed ad libitum on soybeans, split peas, mealworms, and peanuts (spring 2021), and oats, acorns, earthworms, and peanuts (fall 2021), always with corn available as a second choice for reference. In each trial, we used proportion of test bait eaten versus total bait eaten, and relative access to both food sources as indices of bait preference. We found that a higher proportion of corn was consumed than that of any test bait in the spring, but not in the fall. However, we found that earthworms were consumed more than any other test bait in the fall. We also found that corn was accessed more than test baits in the spring, but not more than earthworms or peanuts in the fall. Greater consumption of earthworms relative to other baits, and access rates comparable to corn indicated that earthworms could be an effective alternative bait to corn. Our work suggests that alternative baits may be equally or more effective for attracting wild pigs than corn.

White-tailed deer (Odocoileus virginianus) have been marked with various tags for a wide variety of applications, such as longitudinal, movement, disease, and mark-recapture studies. Tag persistence is critical to all these applications. We used nest survival models in Program MARK to estimate tag retention from 1) 832 free-range white-tailed deer marked with large plastic ear tags in both ears and Passive Integrated Transponder (PIT) tags in the leg and at the base of the ear, and 2) 412 free-range deer marked with metal ear tags in both ears, captured in Texas, USA, 1997USA, -2007. We calculated tag retention from 401 captive deer marked with 2 types of Electronic Identification (EID) ear tags (button or combi) in one ear and 36 captive deer marked with small plastic ear tags in one ear. Annual retention rates were greatest for button EID tags (0.992; 0.983-0.998), combi EID tags (0.979; 0.953-0.996), small plastic ear tags (0.978; 0.965-0.995), and large plastic ear tags (0.958; 0.950-0.965). Passive integrated transponder tags at the base of the ear (0.923; 0.910-0.935) and metal tags (0.909; 0.891-0.924) had fair retention rates. Passive integrated transponder tags placed in the leg (0.779; 0.758-0.800) had the lowest retention rate. Although many factors influence tag selection, EID tags and both small and large plastic tags demonstrate the greatest annual retention rates of both captive and free-range, marked deer. Ó 2017 The Wildlife Society.