Was high grouse bag in early 20th century Norway due to a program for extermination of small game predators?

A Norwegian program for extermination of (small game) predators (NPEP) was run during 1900-1914. This initiative is believed to have caused larger sma ll game stocks and more regional synchrony in rodents. To investigate the e ffectiveness of the NPEP time series of predators bountied (1885-1914), rod ent dynamics (1885-1914), ptarmigan hunting index (1885-1914 and 1900/1-191 4), and willow ptarmigan and berry export statistics (1885-1914) were analy zed for three different regions: south, east and central Norway. In south a nd east Norway there were higher ptarmigan export in the period 1907-1914 t han the years before, but not in central Norway. There was not bountied hig her number of red fox, eagle or goshawk in any of the three regions when co mparing years a) before and after 1900, and b) when comparing the periods 1 900-1906 and 1907-1914. This suggests that predator removal was not the cau se of increased ptarmigan export. The ptarmigan hunting index and rodent in dex for south and cast Norway were correlated in the period 1885-1914, whil e the ptarmigan export from east Norway was correlated with berry export fr om the year before. However, for central Norway the rodent index was not co rrelated with the hunting index. There were cross correlation between berry and ptarmigan export with lag from minus one to nine years for south and e ast Norway. The NAO (North Atlantic Oscillation) - an indication of the win ter weather variation - had higher values during 1900-1914 than 1885-1899, indicating moister and warmer winters in the last period. This analysis ind icates that NPEP generally did not increase predator removal. The results s uggest, however, that it was a series of years with high rodent density, th at caused the increase in ptarmigan populations in south and east Norway, w hich, in turn, may have been caused by favourable weather conditions leadin g to among others good berry crops. Conclusions based on old data series mu st, however, be drawn with caution.