Counting Thames swans is a risky buisness ! . Birds show fight in 50 min census . Six men are carrying out the annual spring count of the swans on the Thames belonging to the King , the Dyers Company and the Vintners Company . The men are searching every yard of the river banks from Pangbourne , Berks , to Putney . Three swan masters , brethren of the companies , are in the expedition . The swans have strong objection . The swans have strong objections to this inquiry into their private lives , and some are powerful ( and bad tempered ) enough to break a man ' s armUsually one man has to hold a swan down while others count the eggs . If there are too many eggs in a nest some are taken away . Photo shows , Pen ( left ) and Cob , two of the King ' s swans , with their eggs at Cookham . Pen the female put up a rigoraus fight against the census . 12 May 1936 *** Local Caption ***