Estate-level decision-making and socioeconomics determine annual harvest in the European Turtle-dove in central Spain

Designing evidence-based policies that regulate harvest levels is essential to avoid unsustainable hunting. This requires a good understanding of the relationship between bag sizes and regulatory mechanisms of harvest, and particularly of how these mechanisms are implemented locally and how they vary between game estates. The European Turtle-dove (Streptopelia turtur) has decreased by 30-49% since the late 1990s. The three main identified threats for the species are habitat loss, illegal killing and unsustainable legal hunting. We assessed how turtle dove estate-level harvest varies in relation to hunter density, number of hunting days, the adopted hunting method, game management intensity and the economic investment of the estate. Additionally, we assessed whether estate-level harvest had declined concomitantly with the population decline, and whether trends had been similar in relation to hunting method. We analysed Hunting Management Plans and Annual Hunting Reports of several thousand estates in central Spain, one of the main breeding and hunting areas of the species. Annual estate harvest was positively associated with hunter density, and was higher on estates that offered fixed-position hunting compared to those that only provided walked-up shooting. Importantly, these decisions are made by managers at the estate level and are not directly regulated by policy. We also found that more turtle doves are harvested on estates that invest more money in management, suggesting that the socioeconomic characteristics of the estate also influence local decisions on harvest intensity. Average annual estate-level harvest declined by 27% between 2007 and 2018, accompanied by a switch from fixed-position to walked-up hunting practices. Our study indicates that reducing hunting density or the number of fixed-position hunting days may be the most efficient ways to reduce turtle dove harvest, and that factors influencing estate-level decision-making have to be understood if reduction of hunting pressure in declining species is sought.

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

Introduction, Material and Methods

Numbers 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.

Results and Discussion

We identified similar, highly significant rates of increase in both data sets for the entire region of Bavaria (IWC 14% [13–15%], bag 13% [12–14%]). Furthermore, in all of the seven Bavarian regions, trends in annual indices of both data sets correlated significantly. The quality of both datasets as indicators of abundances in Greylag geese populations in Bavaria was not undermined by either weaknesses typically associated with citizen based monitoring or problems generally assumed for IWC and bag data. We also show that bag data are, under the German system of collecting bag statistics, a reliable indicator of species’ distribution, especially for detecting newly colonized areas. Therefore, wildlife managers may want to consider bag data from citizen science led monitoring programmes as evidence supporting the decision making processes. We also discuss requirements for any bag monitoring schemes being established to monitor trends in species’ distribution and abundance.