Quantitative Assessment of Bullet Fragments in Viscera of Sheep Carcasses as surrogates for White-Tailed Deer

Abstract

Avian scavengers, such as bald eagles (Haliaeetus leucocephalus), can be exposed to lead through the consumption of spent lead from ammunition in carcasses of animals shot with lead-based projectiles. Few studies have examined the degree of bullet fragmentation in viscera (offal) of game mammals. Our objective was to quantify the number of bullet fragments deposited in sheep carcasses shot with different types of lead and lead-free, high-velocity centerfire rifle bullets and with lead projectiles fired from shotguns and muzzleloader rifles marketed for hunting white-tailed deer (Odocoileus virginianus). We hypothesized that after controlling for velocity, angle of entry, distance from target, and shot placement (thoracic region), most of the bullet fragments would be deposited in the impact zone (heart and lungs). After radiographic examination of all viscera from each carcass, we detected metal fragments in 96% of the viscera and found that metal fragments were deposited in greater quantities in the abdominal viscera (organs caudal to the diaphragm) compared to the thoracic viscera (heart and lungs). Additionally, bullets fired from the centerfire rifle fragmented more than the projectiles fired from the shotgun and muzzleloader rifle. Rapid-expansion lead bullets fragmented more than controlled-expansion lead bullets and lead-free bullets. However, 1 type of controlled-expansion bullet that is comprised almost entirely of lead and advertised to retain >90% of its weight, fragmented similarly to the rapid expansion lead bullets. We observed lead fragments produced by centerfire rifle bullets and shotgun and muzzleloader projectiles present in sheep carcasses and conclude that lead is made available to scavengers from the distribution of lead fragments lodged in the carcasses of game through viscera left in the field by hunters.To eliminate this type of lead exposure, shooters must employ the use of lead-free projectiles or completely remove the remains of shot animals from the field.

Keywords

• avian scavengers
• bullet fragments
• deer hunting
• human–wildlife conflicts
• lead exposure
• lead-free bullets
• offal piles