the Foo bird

there are three man walking in a forest. They have been walking for several hours now and they start to hear a faint bird sound "fooooo foooo" the first guy looks up and a passing bird shits on his head, he wipes it off and dies. The other two men look, but continue to walk. Several more hours pass and the two men start to get tired. They again start to hear a faint bird sound "foooooooo Fooooooo" the second man looks up and a passing bird shits on his head, he was rather tired, but still wipes the shit of his face and dies. The third man looks at the body of his buddy thinks for a minute and continues to walk. Several MORE hours pass and by this time you can guess that the man is extremely tired. after a few minutes the man starts to hear a bird sound "foooooo foooooo" the man dosnt look up and continues to walk. about five minutes pass and the man hears the same bird, only this time its really loud "FOOOOO FOOOOO" the man looks up and the passing bird shits on his face. at this poitn in time the man really dosnt care and he continues walking. He walks for several hours and finialy makes his way out of the forest COMPLETELY unharmed. when the man gets home his wife looks at him and says "where have you been? AND LOOK AT YOUR FACE, lets clean you up" the wife cleans her husbands face and he dies.

    what is the moral of this story?