The Nature Matrix: 354 species, twelve months, one very long scroll.

Plot every entry against the months it is actually in season and the British year turns out to have a very distinct profile — a long shallow winter, a steep climb through April, a June peak, and a slow slide back.

June is the fat month, with 281 of the 354 entries live at once — seabird cities at full volume, butterflies out, orchids up, the shortest nights of the year and every hill loch fishable. January is the lean one at 137, which sounds bleak until you notice what that actually means: a hundred and thirty-seven things are still happening in January. Winter is not empty here. It is geese, wildfowl, murmurations, mountain hares turning white, aurora watches, Geminid meteors, pike season, grayling on the fly, and every all-year mammal and raptor still going about its business.

Look at the gold band across the top of those columns and a second pattern appears. Rare species are far more seasonal than common ones — 26 rare entries are live in June against 7 in January. The scarce things are scarce partly because their windows are narrow, which is exactly why a calendar beats an alphabet.

Rare entries render gold, glow slightly, and sit at the top of every file. Each of the twenty-two expedition files carries at least one, because a checklist with no summit is just a list. But they come with a hard rule, stated on every page: rare is never promised and never chased.

The Scottish wildcat entry is the honest test of the whole system. It is on the board all year and is effectively never seen — there are perhaps a handful of genuinely wild animals left, and the responsible way to encounter one is a camera trap you did not set. It stays in the Matrix because pretending it is not there would be a worse lie than admitting you almost certainly will not see it.

The wallabies, by contrast, are pure delight: a feral colony living wild in the Isle of Man’s northern curraghs since the nineteen-sixties, entirely real and entirely absurd, waiting at the centre of a twenty-eight-day four-nations route.

Fish are the single largest group in the Matrix, and they were the biggest gap when it was first built. Game fishing (wild brown trout in every hill loch and dales beck, sea trout running estuaries on summer nights, grayling on winter fly water, Arctic charr as an ice-age relict in the deep lakes, Lough Neagh’s dollaghan found nowhere else on earth); coarse fishing (pike in Broadland weed beds, perch, roach, rudd, bream, barbel in fast Severn gravel); sea fishing (mackerel off any pier in a summer flat calm, bass in the surf, blue sharks offshore on a charter). Plus the mayfly hatch, which is the only entry in the whole archive that turns an entire river on at once.

Three rules travel with all of it, and the archive states them plainly rather than leaving them for you to discover the expensive way. A rod licence is required for freshwater fishing in England and Wales; Scotland and Northern Ireland run their own permit systems. The coarse close season runs 15 March to 15 June on English rivers. And almost all water is owned or clubbed — a day ticket is the normal price of a cast. Sea fishing needs no licence, but size and bag limits do apply. Check locally, every time.

A gamified wildlife checklist has an obvious failure mode: it turns animals into points and people into collectors who push. So the rule is printed on every nature section, on the A6 card and at the foot of the Matrix itself, and it is not decorative.

Distance, patience, engine off. No nests, no leks, no baiting, no chasing, no crowding. The capercaillie entry says never sought at the lek because disturbing a lekking bird is genuinely damaging. The wild gladiolus is deliberately unmapped. Skomer’s landing cap is celebrated rather than resented, because the cap is the conservation. Nothing in this index is worth disturbing an animal for.

The log records what found you. That is the whole ethic, and it is the reason the scoring rewards patience over pursuit: the rare entries are worth ten points precisely because you cannot go and get them.