Petra from Mississauga Ontario has small pocket holes in her brick mortar that is only a few years old. These are not the weep holes that she knows should be there, but just little holes probably caused by air pockets during construction. How to fill them?
The easiest way to deal with very small patch jobs like this is to use something like Brick Fix that is a latex mortar mix that comes in a caulking tube. The catch is that you want to get a colour match.
Each manufacturer of these patching compounds has a slightly different grey colour, and none of them really match aged mortar. I suggest putting little squirts of the Brick Fix on a non-porous surface and then mix in a drop or two of some kind of brown or black stain. My favourite is heavily boiled Earl Grey Tea (the best antique stain I have ever found, don't know why anyone would ever want to drink the stuff) but any kind of stain will work.
Mix it thoroughly and then let it dry. Only after it is completely dry, compare your samples to the actual wall. When you find a formula (one squirt of mix, two drops of whatever) that works, make up some more and fix the wall.
Don't forget to wet the wall first, that will help the mortar to set better and stick better before it dries.
Generally staining masonary is done with a "lime wash".