Variations in band reporting rate and implications for kill rate in Greater Snow Geese

Abstract

to 2005. We used a spatially explicit multinomial model based on 200 direct recoveries from 4256 banded geese to estimate reporting rate and harvest rate. We found that reporting rate for standard bands varied over time whereas harvest rate was higher in Canada than in the U.S. The reporting probability increased from 0.40 ± 0.11 in the first year of the study to 0.82 ± 0.14 and 0.84 ± 0.13 the second and third years, respectively. Overall, these reporting rates are higher than two previous estimates for this population, which leads to lower estimates of kill rate. However, the large annual differences in reporting rates found in this study lead to uncertainty in the estimation of kill rate. We suggest that the increase in reporting rate in the last two year of the study may be due to the dissemination of information among hunters regarding the presence of reward bands on birds, resulting in increased reporting rate for all bands. This raises issues about the need to adequately inform the public in such large-scale studies to avoid undesirable temporal trends over the course of the study. Nos résultats indiquent que le taux de retour par les chasseurs pour les bagues standards a varié au cours du temps, tandis que le taux de récolte était plus élevé au Canada qu'aux États-Unis. La probabilité de retour de bagues par les chasseurs a augmenté de 0,40 ± 0,11 la première année de l'étude à 0,82 ± 0,14 et 0,84 ± 0,13 les deuxième et troisième années, respectivement. Ces taux de retour de bagues sont supérieurs à ceux estimés précédemment pour cette population, entrainant des estimations du taux de récolte plus faibles. Toutefois, la forte variation interannuelle dans les taux de retour de bagues par les chasseurs observée dans la présente étude engendre une grande incertitude pour l'estimation du taux de récolte. Nous suggérons que l'augmentation du taux de retour de bagues observée au cours des deux dernières années de notre étude pourrait être attribuable à la dissémination de l'information au sein des chasseurs quant à l'existence de bagues récompense sur les oiseaux, conduisant ainsi à une augmentation du taux de retour pour tout type de bagues. Cette étude souligne l'importance des informations à transmettre au public lors d'études à grande échelle afin d'éviter des tendances temporelles indésirables au cours de celles-ci.

Annual survival and seasonal hunting mortality of midcontinent snow geese

“…Thus, we suggest that it is highly unlikely that retrieval rate is constant across the 3 hunting seasons, between age groups, or across breeding latitudes, and suggest that it might also vary with changes in hunting regulations (Schulz et al ). Band reporting rate is also relatively poorly known but may be similarly variable (Souchay et al ). We suspect that some of our estimates (e.g., unusually high winter kill rate for AHY birds from the South in 2003 and 2013) could have reflected variation in λ or c , and suggest that greater attention should be devoted to understanding variation in bird retrieval and reporting rates.…”

A Meta‐Analysis of Band Reporting Probabilities for North American Waterfowl

“…2). If publications included data that had been reported elsewhere (Alisauskas et al 2011 andSouchay et al 2014 included data previously reported in Zimmerman et al 2009), we used only 1 source in our summary. Many recent studies have focused on adult male mallards because they have higher recovery probabilities than females and therefore provide more recovery data per deployed band (Royle and Garrettson 2005).…”

“…Dead recoveries are widely interpreted as being proportional to the fraction of marked individuals that die from a given mortality factor in a given location during a given time interval, but additional variability can accrue from variation in the probability that a dead banded bird that is encountered is subsequently reported (Piper ). Incomplete reporting of banded birds found dead in the wild or harvested by hunters leads to reduced sample sizes, and hence less precise parameter estimates (Wilson et al ), but it can also lead to biased inferences, especially if reporting probabilities are non‐random with respect to other variables of interest (Souchay et al , Naef‐Daenzer et al ).…”

“…Dead recoveries are widely interpreted as being proportional to the fraction of marked individuals that die from a given mortality factor in a given location during a given time interval, but additional variability can accrue from variation in the probability that a dead banded bird that is encountered is subsequently reported (Piper 1995). Incomplete reporting of banded birds found dead in the wild or harvested by hunters leads to reduced sample sizes, and hence less precise parameter estimates (Wilson et al 1989), but it can also lead to biased inferences, especially if reporting probabilities are non-random with respect to other variables of interest (Souchay et al 2014, Naef-Daenzer et al 2016. Bellrose (1945) first addressed the issue of non-reporting of harvested bands using a mail survey of registered Illinois, USA, waterfowl hunters to ask if they had harvested banded ducks during the 1943 or 1944 hunting seasons, and whether they had reported such bands to authorities; approximately 77% of hunters indicated that they had reported bands from harvested birds, but half of all surveyed hunters failed to respond to the questionnaire, and if nonresponsive hunters were also unlikely to report bands, then true band reporting probability could have been substantially lower.…”

Hunter cooperation with requests to avoid a visibly marked ungulate

“…Information on the success of these combined measures in minimizing harvest of marked animals is not well‐documented. Although there is an abundance of literature that has demonstrated the effectiveness of incentive programs designed to increase hunter participation in research involving game species, such programs normally seek to increase the likelihood that hunters will take some desired action such as reporting harvests or completing harvest records (Bellrose , Kilpatrick et al , Royle and Garrettson , Zimmerman et al , Souchay et al ). Unfortunately, the same sort of incentive approach cannot be adopted by researchers to promote the voluntary restraint of actions such as harvesting marked research animals.…”