I've seen references to a canon count of how many magi of each house there are and how many there are in each tribunal but I'm not sure where those came from. can anyone point me towards the right source book?
The Houses of Hermes books and various Tribunal books.
Caution: the numbers are rough estimates, and may not be particularly consistent.
I have always wondered how accurate these numbers are.
I believe that in some Tribunals they only count Magi who are in official Covenants. Which means there is probably a significant population of Magi either not in official Covenants, or in no fixed abode.
How do you count Magi in prolonged Twilight episodes?
Is every Magi death noted?
I think most Magi apprenticeship Gauntlets need to be recorded need to be officially recorded, but the living status of a magus after that could be guesswork.
...which you amazingly compiled in here:
I downloaded that table time ago, before registering in here, and had some fun with it estimating magi in Stonehenge and Loch Leglean for mi Saga.
Hopshackle also did a pretty good simulation of the Order some years ago, here:
Anyway always remember that the Order Population is around 1240, which is pretty much the size of my home village, and I think know everyone there at least by their face. Each tribunal have an average of around 85 magi who will surely know each other pretty well (things like specialties, sigils, houses, companions, grogs, items, preferred spells). With their high life expectancy the death of a magi is big news (specially if he's not very old or if it was noticeable) probably known pretty fast in his Tribunal and soon in the rest of the Order. Think that even if magi can be pretty secretive they have grogs who met other magi's grogs and gossip around them and spread news around; if you wonder about another magus wereabouts one pretty good option is turning and asking your shield grog about him... the second effortless one is asking your local Redcap. And the third, going to the nearest village to his covenant and asking there. Peasants have boring lifes and you can expect them to know a lot of stuff about the weird old dudes living in that enchanted tower right over there.
There surely are lonewolfs out there but being odd and strange they are probably the focus of more gossip and scrutiny than usual by both magi and mundanes.
This is something often overlooked, but in my Saga I like to make the magi notice that they are part of a small privilegded and closed society, powerful but fragile. We don't have encounters with a random Flambeau magus in the deep of the forest: we find a Flambeau and magi can guess he must be that Provencal's dude the big mouthed Merinita from the neighbour covenant mentioned a couple a months ago, saying that he wrote a letter to a friend of hers talking about paying a visit looking looking for some kind of item his parens lost here during his young years, which was some kind of staff or maybe a sword, because his parens was one of these odd Flambeau fond of cutting through beasts instead of just roasting them.
Glad someone's found it useful.
Gauntlets, attendance at Tribunal, official communications with quaesitores, and official contacts with Redcaps all lead to records of some kind or another. If you don't do most of these things, you can go without being noticed in a historical sense.
In the Rhine, there's a tradition of voting a missing magus' sigil - the mage may have entered a long Twilight, or possibly be traveling in Faerie - a practice referred to by non-Rhine magi as corruption. This doesn't seem to be widely followed in other Tribunals.
Certainly not every mage's death is noted. Some go on expeditions and simply vanish. In Provencal a quaesitor just up and disappeared one day on an apparently short journey.
I suspect that the Redcaps have good, if incomplete records of which magi reside where, and where guests are if they stay longer than a Season. Practice probably varies, but I'd think the Redcaps want to know about how many magi live in a covenant, in order to manage carrying resources.
The formal rules for Wizard's War practically require every living magi have a current legal address.
I'd imagine that requirement is detailed in the peripheral code of most tribunals.