Lining Up For Bed

I'm pretty sure that such things must happen to other photographer out there, but I often find myself in a situation where I go out with the intention of photographing one thing, and then ending up with something else.  The other night, I headed out to capture the sunset in the trees of a park close to the Head Office.  After getting there, I heard the familiar noise of the pigeons and their fluttering wings.  I looked over to my right and found a group had gathered on a light post, and one by one.  So, plans changed and I got a little closer to the light post and waited for one to make the jump.  The photograph was taken at f/4, 1/4000sec, ISO 100 at 70mm.  As with most sunset photos, I underexposed the image in order to get more colour in the sky and to darken my fine feathered friends. I also tried to position myself so that I had some branches in the bottom of my shot as I though to added a little something more to the photo.  So, what is the lesson to be had?  Keep your eyes open, you may ended up seeing more than you thought you would see.