Adjusting for body mass change in white‐tailed deer during hunting season

Abstract

ABSTRACT Age‐specific body mass is a variable of interest to managers and hunters of white‐tailed deer (Odocoileus virginianus). Long hunting seasons across much of the southern United States include most of the period of active rut, when individual body mass fluctuates over time. Adjusting body mass for harvest date would improve accuracy of age‐specific mass estimates and enable managers to make valid comparisons among years with different harvest patterns. We used 17 years (1991–2007) of harvest records from the Delta, Thin Loess, and Lower Coastal Plain (LCP) soil regions of Mississippi, USA, to develop age‐ and region‐specific models of average daily mass at harvest for male and female deer over a 121‐day hunting season. Models of female mass peaked in early winter near median population conception date. Among females, yearling mass exhibited the most marked fluctuations, with a projected increase of 7.3% from the start of hunting season to its seasonal peak. Modeled mass of harvested males fluctuated more strongly, peaking well before median conception date and decreasing an average of 13.8% from seasonal peak to the end of hunting season. Harvest mass of prime‐aged (5.5–7.5 years old) males began decreasing earliest in all regions, reflecting earlier participation in rut, and mass of older males always peaked earlier than younger males in the Delta and Thin Loess. In the LCP, projected peak male body mass did not correlate with age class and spacing between dates of peak mass was greatly truncated relative to other regions. Different patterns of mass change between the LCP and other regions may be explained by later breeding, greater overlap of rut‐related and seasonal hypophagy, and lower nutritional plane. Models to correct body mass for harvest date should be specific to sex and age class and distinguish among adjacent populations with different mating season phenology. © 2017 The Wildlife Society.

Keywords

• body mass adjustment
• conception date
• harvest date
• hunting season
• Odocoileus virginianus
• rut