As most wfp cleaners know, it is possible to remove bird crap and other objects from the glass, all you do is fit a scraper onto a pole and scrape away.
For the last few months I have being using a different method which does the job perfectly.
You will need a bit of Velcro (the rough part) and some Glue.
Now all you need to do is apply the glue to the top edge of your brush head, wait for it to almost dry, then attached the Velcro.
Next time you come across some crap, just swivel the brush and scrape away.