When 4 foot tall birds attack...
I'm not sure if this is a 4 foot tall Kiwi bird
if it's a 4 foot tall humming bird:
But I have a feeling that when you saw this picture you thought,
OMG! Every morning I stroll down the street with my morning cup of coffee. What would I do if this 4 foot creature came running towards me(full throttle) in attack mode! How would I defend myself?! How would I fight back?!
Well I don't have the answer to your question
maybe a good idea would be to distract the bird by making small talk.
In the middle of this distraction gently knock it over(they look like they are the type to have a hard time getting back up when they fall down).
Once you do this, run for your life.