Pigeon behaviour

Question
I have a friend who has a pigeon on a nest on her balcony.  There are two other pigeons that seem to be picking on this nesting mum.  They have pecked her head and it looks very sore.  Is there anything that she can do to help the victim.  One of the eggs has now rolled out of the nest but the other is still there.  Her and her partner are finding the whole situation very stressful.  Can you advise them of how they can help?

Answer
I'm assuming these are wild birds?  If so, it wouldn't work to try containing them (thereby fencing out the intruders).  Ideally,  pigeon nest areas have a small entrance so that they can defend it more easily.  If there is a way she can stack a few bricks or something similar so that the male can defend her easier, your friend may be able to help.  Otherwise, nature will have to play out.

Dave