Citizen Science Based Monitoring of Greylag goose (Anser anser) in Bavaria (Germany): Combining Count Data and Bag Data to Estimate Long-Term Trends between 1988/89 and 2010/11

摘要

Introduction, Material and MethodsNumbers of large grazing bird (geese, swans, cranes) have increased all over Europe, but monitoring these species, e.g. for management purposes, can be time consuming and costly. In Bavaria, sedentary Greylag geese (Anser anser) are monitored during the winter by two different citizen-based monitoring schemes: the International Waterbird Census [IWC] and hunting bag statistics. We compared the results of both schemes for the seasons 1988/89 to 2010/11 by analysing annual indices calculated using the software TRends and Indices for Monitoring Data—TRIM.