Dynamics of birding

I find it amusing how it will often take me a long time to find a particular bird for the first time, yet once I have found it I seem to find them everywhere. This has happened with:

• Australasian Pipits (saw my first near Dampier recently, have now seen them 2 minutes from the office in an area I had looked before);
  
• Western Spinebills (first seen in Pinnaroo a few years back, we now have a family of them frequenting the backyard);
• Australian Reed-Warblers (seen first on a BAWA walk, now I see them in the reeds everywhere);
• Brown Honeyeaters (for years I thought they were small Singing Honeyeaters);
  
• Common Greenshanks (seen first on a BAWA walk, now I see them all the time in Dampier).

I suspect that the same will happen with the Little Grassbird and a few other conspicuous absentees from my list.