Duck harvest and crippling in Illinois in 2018-19

Crippling loss (waterfowl downed, but not retrieved) is a recognized
component of waterfowl harvest, but there are few contemporary estimates.
We used a zero-inflated negative binomial model to account for false
reporting of zeros and estimated true waterfowl crippling losses from
harvest data reported in a 2018–19 survey of waterfowl hunters in
Illinois, USA. We found that crippling rates declined rapidly with
increasing harvest and moderately with increasing days afield. For the
most active hunters (days afield), the probability of falsely reporting
zero crippling loss increased with the number of ducks they reported
harvesting, whereas for the least active hunters we found the reverse. We
suggest that modest improvements in hunter skill could produce significant
reductions in crippling loss.