Decline of the Stag Beetle

I have been in Hillingdon for the last ten springs and this is the first time I have seen no stag beetles at all. I think the problem is the succession of wet springs. The mating season for the staggies is the end of May, beginning of June, but night after night was rainy, blowy or cold, the very weather stag beetles hate. Now we have had a few barmy nights in late June, but I fear it is too late. The ones that hatched have failed to mate and will have died by now. The population has been in decline round here for a decade. Perhaps they have now died out altogether in this area.