How to Spot a Creeper ( A Brown Creeper that is)

So there we were, looking for new birds.. and I spotted something moving!! It couldnt be... Yes, Yes... a Brown Creeper!!
Now, for the non birders out there.. Just to show you what a difficulty this was... This is a tree trunk with the creeper hiding.. Zoomed quite in, you can Just see the feathers!

I got lucky, and spotted him going up the tree, with the white belly quite visible.. Unfortunately I looked away for a SPLIT SECOND... and lost it.. never did spot it again..