i was watching a nest once and the little birds kept scratching and pecking at themselves.. then i realized the poor things had lice ... imagine lice on them so bad that they could not stop scratching.. to me this was the most horrible thing i witnessed in nature being cruel.. i went on to see alot more after that but i never forgot this little nest full of babies.. it is mind boggling all the things that animals endure.. nature is wonderful but can be so cruel..
