Will mourning dove crippling rates increase with nontoxic-shot regulations?

Increasing concerns about the exposure of mourning doves (Zenaida macroura) to spent lead shot may lead to a review of lead-shot restrictions. Policy reviews regarding current restrictions likely will involve debates about whether nontoxic-shot requirements will result in increased crippling loss of mourning doves. We evaluated waterfowl crippling rates in the United States prior to, during, and after implementation of nontoxic-shot regulations for waterfowl hunting. We use this information to make inferences about mourning dove crippling rates if nontoxic-shot regulations are enacted. We found differences in moving average crippling rates among the 3 treatment periods for ducks (F=23.232, P < 0.001, n=49). Prenontoxic-shot-period crippling rates were lower than 5-year phase-in period crippling rates (P = 0.043) but higher (P < 0.001) than nontoxic-shot-period crippling rates. Similarly, we observed differences in moving average crippling rates among the 3 treatment periods for geese (F=9.385, P < 0.001, n=49). Prenontoxic-shot- and 5-year-phase-in- period crippling rates were both greater than (P < 0.001) nontoxic-shot-period crippling rates but did not differ from one another (P = 0.299). Regardless of why the observed increases occurred in reported waterfowl crippling rates during the phase-in period, we believe the decline that followed full implementation of the nontoxic-shot regulation is of ultimate importance when considering the impacts of lead shot restrictions for mourning doves. We argue that long-term mourning dove crippling rates might not increase as evidenced from historical waterfowl data.