Okay, so. I hate field bossing.
Since the charts around here (gosh there are so many) are bound to cause confusion, let me just go ahead and say:
Every chart you see for field boss spawns in NA is going to be at least partially wrong
I'm not saying this to offend anyone who has spent a great deal of time working on their charts, but it's true.
First off, many charts floating around, from the ones in this thread to the one on the mabinogi world wiki, still list the Prairie Dragon as spawning within a set period of time each weekday. That is incorrect. It is an all day spawn.
Many charts also list weekday spawns as taking place within 2-hour periods. That is also generally incorrect.
Many of the spawns appear to happen within a 3-hour period.
So far, I think the most accurate chart we have would be the above one, from GameAbout.
It is also incorrect.
It is missing the second weekend spawn time for the Mammoth, (which I'm reasonably sure exists), and the spawn times it gives for the Black, (and of course White) dragon are completely wrong for our servers. Those spawn times are available on the NA Mabi website
here. There may or may not be minor flaws with the timing for the other bosses.
Maybe one day we'll have a perfect chart.
:fail3: