Effect of Body Condition on Vulnerability of Greater Snow Geese to Hunting and Capture

Abstract

Several studies have suggested that ducks in poor condition are more likely to be captured for banding or recovered by hunters than those in good condition (condition-bias hypothesis). We tested the hypotheses that samples of greater snow geese (Chen caerulescens atlantica) captured with baited cannon-nets, and shot by hunters in fall at the Cap Tourmente National Wildlife Area, Quebec, were not biased toward birds in poor condition. Density of birds and the frequency of aggressive interactions at baited capture sites were higher than at unbaited sites. Overall, condition indices of geese captured in baited and unbaited cannon-nets did not differ for both adults and juveniles. Even though geese caught with cannon-nets may be a heterogeneous sample, we argue that they are nonetheless representative of the population with respect to body condition and social status. Mean condition indices of juveniles captured with cannon-nets did not differ from those shot by hunters, but adults shot by hunters were on average heavier than those captured. There was no difference in mass of abdominal fat between geese captured with cannon-nets and those shot by hunters. We used body mass corrected for structural size and recovery data from 2,242 geese banded during October 1993-95 at Cap Tourmente to test whether geese in poor condition at the time of banding had a higher probability of being recovered by hunters. Among 12 separate analyses (by year, sex, and age), only 2 revealed a significant negative relationship (juvenile males and females in 1995) between condition of banded birds and recovery rate. We conclude that our results provided little evidence that greater snow geese captured at baited cannon-nets or shot by hunters were biased toward birds in poor condition.