-- Loaded ecology, persisted calendar ages. No emergence, items or player combat.
return function(hearth, api)
	local modpath=api.get_modpath and api.get_modpath("hearth")
	local F=hearth.fauna or dofile(assert(modpath,"wildlife needs fauna or get_modpath").."/fauna.lua")(hearth,api)
	local GLOBAL,PLAYER,LOCAL,RADIUS,BUDGET=64,16,12,48,24
	local DAY,MAX=86400,9007199254740991
	local REGION,FOUNDERS,REGION_LIMIT,REGISTRY_BYTES=48,4,4096,1048576
	local STORAGE_KEY="wildlife_residents_v1"
	local records,order={},{}
	for _,r in ipairs(F.list()) do records[r.id]=r; order[#order+1]=r.id end
	local active,counts={},{}
	for _,id in ipairs(order) do counts[id]=0 end
	local total,serial,actions,births,meals,grazed,dung,deaths,pollinations,dispersals,detritus=0,0,0,0,0,0,0,0,0,0,0
	local clock,credit,recruitment,cursor,recruit_kind,player_cursor=0,0,0,0,0,0
	local candidate_cursor,patch_cursor=0,0
	local recruiting={attempts=0,successes=0,scans=0,last_reason="waiting",reasons={}}
	local directions={{1,0},{1,1},{0,1},{-1,1},{-1,0},{-1,-1},{0,-1},{1,-1}}
	local offsets={{16,0},{0,16},{-16,0},{0,-16},{20,8},{-20,-8},{8,-20},{-8,20}}
	local function finite(n) return type(n)=="number" and n==n and math.abs(n)<math.huge end
	local function epoch(n) return finite(n) and n>=0 and n<=MAX and n%1==0 end
	local function decimal(n) return string.format("%.0f",n) end
	local function now()
		local t=api.now and api.now() or os.time()
		return epoch(t) and t<=MAX-366*DAY and t or nil
	end
	local function delta(t) return finite(t) and t>0 and math.min(t,1) or 0 end
	local function valid(p)
		if type(p)~="table" then return false end
		for _,a in ipairs({"x","y","z"}) do if not finite(p[a]) or math.abs(p[a])>30900 then return false end end
		return true
	end
	local function players()
		return api.get_connected_players and api.get_connected_players() or {}
	end
	local function log(reason)
		if api.log then api.log("warning","[hearth wildlife] "..reason) end
	end
	-- Flat, explicitly versioned JSON. Region values are a bounded canonical
	-- journal: attempts/last-attempt/id=species;... . Never evict or truncate.
	local storage=hearth.storage
	if not storage and api.get_mod_storage then
		local ok,s=pcall(api.get_mod_storage); if ok then storage=s end
	end
	local ledger={version=1,counter=0}; local regions,region_count={},0
	local storage_ok=storage and type(storage.get_string)=="function" and type(storage.set_string)=="function" or false
	local function fail_storage()
		if storage_ok then log("resident registry unavailable or invalid; new admissions disabled") end
		storage_ok=false; return false
	end
	local function region_key(p) return "r_"..math.floor(p.x/REGION).."_"..math.floor(p.z/REGION) end
	local function valid_region(k)
		if type(k)~="string" then return false end
		local x,z=k:match("^r_(-?%d+)_(-?%d+)$")
		x,z=tonumber(x),tonumber(z)
		return x and z and math.abs(x)<=644 and math.abs(z)<=644
			and k=="r_"..x.."_"..z
	end
	local function flat(text,limit)
		return type(text)=="string" and #text>0 and #text<=limit
			and text:sub(1,1)=="{" and text:sub(-1)=="}"
			and not text:sub(2,-2):find("[{}%[%]]")
	end
	local function read_registry()
		if not storage_ok or not api.parse_json or not api.write_json then return fail_storage() end
		local ok,text=pcall(storage.get_string,storage,STORAGE_KEY)
		if not ok or type(text)~="string" then return fail_storage() end
		if text=="" then return true end
		if not flat(text,REGISTRY_BYTES) then return fail_storage() end
		local parsed; ok,parsed=pcall(api.parse_json,text,nil,true)
		if not ok or type(parsed)~="table" or getmetatable(parsed) or parsed.version~=1
			or not epoch(parsed.counter) then return fail_storage() end
		local used={}
		for k,v in pairs(parsed) do
			if k~="version" and k~="counter" then
				if not valid_region(k) or type(v)~="string" or #v>256 or region_count>=REGION_LIMIT then return fail_storage() end
				local attempts,time,members=v:match("^(%d+)/(%d+)/(.*)$")
				attempts,time=tonumber(attempts),tonumber(time)
				if not epoch(attempts) or attempts>1000000000 or not epoch(time) then return fail_storage() end
				local r={attempts=attempts,time=time,members={}}; local rebuilt=""
				for n,id in members:gmatch("(%d+)=([%w_]+);") do
					local individual=tonumber(n)
					if not epoch(individual) or individual<1 or individual>parsed.counter or used[individual]
						or not records[id] or #r.members>=FOUNDERS or decimal(individual)~=n then return fail_storage() end
					used[individual]=true; r.members[#r.members+1]={id=individual,species=id}
					rebuilt=rebuilt..n.."="..id..";"
				end
				if rebuilt~=members then return fail_storage() end
				regions[k]=r; region_count=region_count+1
			end
		end
		ledger=parsed; return true
	end
	local function persist()
		if not storage_ok then return false end
		local ok,text=pcall(api.write_json,ledger)
		if not ok or not flat(text,REGISTRY_BYTES) then return fail_storage() end
		local written; ok,written=pcall(storage.set_string,storage,STORAGE_KEY,text)
		if not ok or written==false then return fail_storage() end
		local verified; ok,verified=pcall(storage.get_string,storage,STORAGE_KEY)
		if not ok or verified~=text then return fail_storage() end
		return true
	end
	local function journal(k,r)
		local v=decimal(r.attempts).."/"..decimal(r.time).."/"
		for _,m in ipairs(r.members) do v=v..decimal(m.id).."="..m.species..";" end
		ledger[k]=v
	end
	local function region(k,time,attempt)
		if not storage_ok then return nil end
		local r=regions[k]
		if not r then
			if region_count>=REGION_LIMIT then return nil end
			r={attempts=0,time=time,members={}}; regions[k]=r; region_count=region_count+1
		end
		if attempt then r.attempts=math.min(1000000000,r.attempts+1); r.time=time end
		journal(k,r); return persist() and r or nil
	end
	local function identity(id,p,time,founder)
		if not storage_ok or ledger.counter>=MAX then return nil end
		local k=founder and region_key(p) or ""
		local r=founder and region(k,time,false) or nil
		if founder and (not r or #r.members>=FOUNDERS) then return nil end
		ledger.counter=ledger.counter+1.0 -- avoid narrow-integer wrap; exact through MAX
		if r then r.members[#r.members+1]={id=ledger.counter,species=id}; journal(k,r) end
		if not persist() then return nil end
		return ledger.counter,k
	end
	read_registry()
	if not storage_ok then log("new wildlife needs a healthy resident registry; saved animals are retained") end
	local function at(p,x,y,z) return {x=p.x+x,y=p.y+y,z=p.z+z} end
	local function cell(p) return {x=math.floor(p.x+.5),y=math.floor(p.y+.5),z=math.floor(p.z+.5)} end
	local function dist(a,b) return (a.x-b.x)^2+(a.y-b.y)^2+(a.z-b.z)^2 end
	local function permitted(p)
		if not valid(p) then return false end
		if hearth.claim_owner_at then
			local owner,ambiguous=hearth.claim_owner_at(p)
			if owner or ambiguous then return false end
		end
		local protect=hearth.external_protected or api.is_protected
		return type(protect)=="function" and not protect(p,"")
	end
	local function node(p)
		if not permitted(p) then return nil end
		local n=api.get_node_or_nil(p); return n and n.name~="ignore" and n or nil
	end
	local function season(time)
		local climate=hearth.climate_at and hearth.climate_at(time)
		return climate and climate.season or (hearth.seasons and hearth.seasons.season and hearth.seasons.season()) or nil
	end
	local markers={"owner","planter","placed_by","player_placed","hearth_placed","hearth_player_placed","planted_at"}
	local function unmarked(p)
		local m=api.get_meta(p)
		for _,k in ipairs(markers) do local v=m:get_string(k); if v~="" and v~="0" then return false end end
		if m.to_table then
			for k,v in pairs((m:to_table() or {}).fields or {}) do
				local harvest=k=="botany_ready_at" and tonumber(v)
					and finite(tonumber(v)) and tonumber(v)>=0
				if k:sub(1,5)~="succ_" and not harvest and v~="" and tostring(v)~="0" then return false end
			end
		end
		return true
	end
	local function natural(p,n)
		return n~=nil and api.get_meta(p):get_string("succ_natural")=="1" and unmarked(p)
	end
	local function water(n) return n and (n.name=="hearth:water_source" or n.name=="hearth:water_flowing") end
	local function ground(n)
		return n and (n.name=="hearth:grass" or n.name=="hearth:soil"
			or (hearth.diversity and hearth.diversity.is_ground(n)))
	end
	local function legacy_flora(n)
		local k=n and (hearth.seasons and hearth.seasons.kind(n) or n.name:match("^hearth:(.+)$"))
		return k=="meadow_grass" or k=="fern" or k=="wildflowers"
	end
	local function clear(p)
		local n=node(p)
		if not n then return false end
		if n.name=="air" then return true end
		local d=(api.registered_nodes or {})[n.name]
		local D=hearth.diversity
		-- Collision observation is not a meal or adoption: recognizable unmarked
		-- mapgen understory is passable even outside succession's adoption ring.
		local below=at(p,0,-1,0)
		local B=hearth.botany
		local plant=B and B.get and B.get(n.name)
		local flora=((D and D.is_worldgen_flora and D.is_worldgen_flora(n)) or legacy_flora(n)
			or (plant and not plant.existing))
			and unmarked(p) and unmarked(below) and ground(node(below))
		return (natural(p,n) or flora) and d~=nil and d.walkable==false and not water(n)
	end
	local function medium(p,r)
		if water(node(cell(at(p,0,.05,0)))) then
			return (r.medium=="swim" or r.medium=="amphibian") and "swim" or nil
		end
		if r.medium=="swim" then return nil end
		return r.medium=="fly" and "fly" or "land"
	end
	local function safe(p,id)
		local r=records[id]; if not r or not valid(p) then return false end
		local mode=medium(p,r); if not mode then return false end
		local b=r.bounds; local radius=math.max(-b.min[1],b.max[1],-b.min[3],b.max[3])+.04
		-- Full yaw-independent body envelope. Flight is a low corridor above
		-- natural terrain, never a shortcut across cliffs or unobserved water.
		for _,x in ipairs({-radius,0,radius}) do for _,z in ipairs({-radius,0,radius}) do
			for _,y in ipairs({.03,b.max[2]*.5,b.max[2]+.08}) do
				local q=cell(at(p,x,y,z))
				if mode=="swim" then if not water(node(q)) then return false end
				elseif not clear(q) then return false end
			end
			if mode~="swim" then
				local supported=false
				for depth=0,(mode=="fly" and 3 or 0) do
					-- A Creatura spawn may start at integer ground-level while our
					-- scanner starts at the half-node surface center. Sample below
					-- either valid feet convention; the rest of the swept body uses
					-- the same collision envelope and never teleports/creates terrain.
					if ground(node(cell(at(p,x,-.6-depth,z)))) then supported=true; break end
				end
				if not supported then return false end
			end
		end end
		return true,mode
	end
	local function path(a,b,id)
		if not valid(a) or not valid(b) or dist(a,b)>4 then return false end
		local _,start=safe(a,id); if not start then return false end
		local length=math.sqrt(dist(a,b))
		local steps=math.max(1,math.ceil(length/.2))
		for i=0,steps do
			local t=i/steps; local q={x=a.x+(b.x-a.x)*t,y=a.y+(b.y-a.y)*t,z=a.z+(b.z-a.z)*t}
			local ok,m=safe(q,id)
			-- Refuse shore transitions until a fully swept ramp exists.
			if not ok or m~=start then return false end
		end
		return true
	end
	local function nearby(p,r,id,exclude)
		local n=0
		for e in pairs(active) do
			local q=e.object:get_pos()
			if e~=exclude and valid(q) and (not id or e.kind==id) and dist(p,q)<=r*r then n=n+1 end
		end
		return n
	end
	local function room(p,id,restored,exclude)
		-- Caps are admission limits, never a reason to erase an existing animal
		-- (including movement and engine activation before players join).
		if restored then return true end
		if not exclude and (total>=GLOBAL or counts[id]>=records[id].cap) then return false end
		if nearby(p,16,nil,exclude)>=LOCAL then return false end
		local close=false
		for _,player in ipairs(players()) do
			local q=player:get_pos()
			if valid(q) and dist(p,q)<=RADIUS*RADIUS then
				close=true; if nearby(q,RADIUS,nil,exclude)>=PLAYER then return false end
			end
		end
		-- Saved creatures activate before the first player joins. Proximity gates
		-- new immigration only, not persistent restoration.
		return close
	end
	local function forget(e)
		if active[e] then active[e]=nil; total=total-1; counts[e.kind]=counts[e.kind]-1 end
	end
	local function remove(e,death)
		if not active[e] then return false end
		forget(e); if death then deaths=deaths+1 end
		e.object:remove(); return true
	end
	local function animation(e,name)
		if e.clip==name then return end
		e.clip=name; local c=records[e.kind].clips[name]
		e.object:set_animation({x=c[1],y=c[2]},24,.15,true)
	end
	local function stop(e,clip)
		e.target={x=0,y=0,z=0}; e.velocity={x=0,y=0,z=0}; e.lease=0
		e.object:set_velocity(e.velocity); animation(e,clip or "idle")
	end
	local allowed={version=true,species=true,born_at=true,origin=true,sex=true,foodreserve=true,
		resident_id=true,founder_region=true,hunger_seconds=true,
		nextfeed=true,pregnancy_until=true,last_seen=true,seed=true,last_meal=true,dung_pending=true,
		conception_at=true,litter_remaining=true,litter_delivered=true,litter_total=true,
		nextbreed=true,last_birth_at=true,parent_seed=true,parent_born_at=true}
	local reproductive={"conception_at","litter_remaining","litter_delivered","litter_total","nextbreed","last_birth_at"}
	local function development(p)
		return p and (p.reproduction=="egg" and p.incubation_days or p.gestation_days)
	end
	local function validate(s,id,time)
		if type(s)~="table" or getmetatable(s)~=nil then return nil end
		for k in pairs(s) do if not allowed[k] then return nil end end
		if s.version~=1 or s.species~=id or not records[s.species] then return nil end
		if s.resident_id~=nil or s.founder_region~=nil then
			if not epoch(s.resident_id) or s.resident_id<1 or
				(s.founder_region~="" and not valid_region(s.founder_region)) then return nil end
		end
		if s.hunger_seconds==nil then s.hunger_seconds=0 end -- legacy loaded hunger was not recorded
		if not finite(s.hunger_seconds) or s.hunger_seconds<0 or s.hunger_seconds>MAX then return nil end
		if not epoch(s.born_at) or not epoch(s.last_seen) or not epoch(s.last_meal)
			or s.born_at>time or s.last_seen>time or s.last_seen<s.born_at
			or s.last_meal>s.last_seen or s.last_meal<s.born_at then return nil end
		if s.origin~="established" and s.origin~="born" then return nil end
		if s.sex~="male" and s.sex~="female" and not (id=="earthworm" and s.sex=="hermaphrodite") then return nil end
		if not finite(s.foodreserve) or s.foodreserve<0 or s.foodreserve>1 then return nil end
		if not epoch(s.seed) or s.seed>2147483646 or not epoch(s.nextfeed) or s.nextfeed>time+DAY then return nil end
		if type(s.dung_pending)~="boolean" or not epoch(s.pregnancy_until) then return nil end
		-- Migrate only the old empty reproductive state, never an old pregnancy.
		local missing=0; for _,k in ipairs(reproductive) do if s[k]==nil then missing=missing+1 end end
		if missing==#reproductive and s.pregnancy_until==0 then
			for _,k in ipairs(reproductive) do s[k]=0 end
		elseif missing>0 then return nil end
		if s.parent_seed==nil and s.parent_born_at==nil then s.parent_seed=0; s.parent_born_at=0 end
		if not epoch(s.parent_seed) or s.parent_seed>2147483646 or not epoch(s.parent_born_at)
			or s.parent_born_at>s.born_at then return nil end
		for _,k in ipairs(reproductive) do if not epoch(s[k]) then return nil end end
		if s.last_birth_at>s.last_seen then return nil end
		local p=records[id].profile; local d=development(p)
		local enabled=p and p.reproduction_enabled==true
		local care=enabled and p.postpartum_days*DAY or 0
		if s.nextbreed>time+care+(enabled and d.max*DAY or 0) then return nil end
		if s.last_birth_at>0 and s.nextbreed<s.last_birth_at+care then return nil end
		if s.pregnancy_until==0 then
			if s.conception_at~=0 or s.litter_remaining~=0 or s.litter_total~=0 or s.litter_delivered~=0 then return nil end
		else
			if not enabled or s.sex~="female" or s.conception_at<s.born_at+p.maturity_days.max*DAY
				or s.conception_at>s.last_seen
				or (s.last_birth_at>s.conception_at and s.litter_delivered==0)
				or s.pregnancy_until~=s.conception_at+math.ceil(d.max*DAY)
				or s.pregnancy_until>time+math.ceil(d.max*DAY)
				or s.litter_total<p.birth_count.min or s.litter_total>p.birth_count.max
				or s.litter_remaining<1 or s.litter_delivered+s.litter_remaining~=s.litter_total
				or (s.litter_delivered>0 and s.last_birth_at<s.pregnancy_until) then return nil end
		end
		return s
	end
	local function decode(data,id,time)
		if not flat(data,2048) or not api.parse_json then return nil end
		-- Flat schema only: reject deep parser input before decoding; suppress
		-- engine JSON diagnostics so hostile raw data never reaches the logs.
		if data:sub(1,1)~="{" or data:sub(-1)~="}" or data:sub(2,-2):find("[{}%[%]]") then return nil end
		local ok,s=pcall(api.parse_json,data,nil,true)
		return ok and validate(s,id,time) or nil
	end
	local function encode(s,id,time)
		if not validate(s,id,time) or not api.write_json then return nil end
		local ok,text=pcall(api.write_json,s)
		return ok and type(text)=="string" and #text<=2048 and text or nil
	end
	local function initial(id,time,seed)
		local p=records[id].profile; local maturity=p and p.maturity_days; local age=0
		-- Upper maturity endpoint yields an explicitly estimated adult cohort,
		-- not a random juvenile advertised as an established adult.
		if maturity then age=maturity.max*DAY end
		return {version=1,species=id,born_at=math.max(0,time-math.ceil(age)),origin="established",
			hunger_seconds=0,
			sex=id=="earthworm" and "hermaphrodite" or (seed%2==0 and "female" or "male"),
			-- Imported wild individuals are not credited a simulated meal.
			foodreserve=.5,nextfeed=time,pregnancy_until=0,last_seen=time,seed=seed,last_meal=time,dung_pending=false,
			conception_at=0,litter_remaining=0,litter_delivered=0,litter_total=0,nextbreed=0,last_birth_at=0,
			parent_seed=0,parent_born_at=0}
	end
	local function prey_for(e,p,range)
		local best,found=range*range,nil
		for other in pairs(active) do
			local q=other.object:get_pos()
			if other~=e and records[e.kind].prey[other.kind] and valid(q) and dist(p,q)<best
				and safe(q,other.kind) then found,best=other,dist(p,q) end
		end
		return found,best
	end
	local function edible(p,n,time,food)
		if not natural(p,n) then return nil end
		local B=hearth.botany; local s=season(time)
		if B and B.kind(n) then
			local id=B.kind(n)
			if food=="nectar" and B.pollinator(n,s) then return id end
			if food=="fruit" and B.edible(n,s) then return id end
			if food=="browse" and B.has_tag(n,"browse") then
				if B.browse(n,s) then return id,"herbivore" end
				-- A tagged, non-toxic woody perennial may offer twigs/stems while
				-- dormant. This is not human edibility; the shared forage transaction
				-- must explicitly accept the winter_browse mode before credit is earned.
				local r=B.get(id)
				if s=="Winter" and r and (r.group=="trees" or r.group=="shrubs") and not r.toxic then
					return id,"winter_browse"
				end
			end
			-- Succession currently debits only represented oak/hazel nuts, not
			-- every herb's qualitative seeding season as fictional bird food.
			if food=="seed" and (id=="hazel" or id=="oak") and B.seeding(n,s) then return id end
			return nil
		end
		local k=hearth.seasons and hearth.seasons.kind(n.name) or n.name:match("^hearth:(.+)$")
		if food=="browse" and (k=="meadow_grass" or k=="fern") then
			if not hearth.seasons or hearth.seasons.available(k) then return k,"herbivore" end
			if s=="Autumn" or s=="Winter" then return k,"winter_browse" end
		end
	end
	local function resources(e,p,time,foods)
		foods=foods or records[e.kind].foods
		local c=cell(at(p,0,.1,0)); local candidates={}
		-- A fixed 5x5 search finds nearby food without scaling with population or
		-- walking the map; path validation still decides whether it is reachable.
		for x=-2,2 do for z=-2,2 do
			local q=at(c,x,0,z); local n=node(q)
			if natural(q,n) then
				for _,food in ipairs({"nectar","litter","fruit","seed","browse"}) do
					if foods[food] then
						local id,browse_mode
						if food=="litter" and n.name=="hearth:litter" then id="litter"
						else id,browse_mode=edible(q,n,time,food) end
						if id then candidates[#candidates+1]={pos=q,id=id,food=food,browse_mode=browse_mode} end
					end
				end
			end
		end end
		return candidates
	end
	local function observe_habitat(p)
		local S=hearth.succession
		if not S or not S.habitat then return nil end
		local q=cell(at(p,0,.1,0))
		-- Succession observes the stand ABOVE a water substrate, not its bottom.
		if water(node(q)) then q=at(q,0,1,0) end
		local h=S.habitat(q)
		return h and h.loaded==true and h or nil
	end
	local function habitat(p,id,time,observed,food,allow_ambient)
		local h=observed or observe_habitat(p)
		if not h then return false end
		local r=records[id]
		if r.medium=="amphibian" or r.medium=="swim" then
			if (h.water or 0)+(h.near_water or 0)<=0 then return false end
		end
		if id=="earthworm" or id=="common_frog" or id=="smooth_newt" then
			if (h.moisture or 0)<.5 then return false end
		end
		if id=="red_squirrel" and (h.canopy or 0)<=0 then return false end
		if (id=="bank_vole" or id=="wood_mouse") and (h.cover or 0)<=0 then return false end
		local probe={kind=id}
		local ambient={robin=true,blackbird=true,blue_tit=true}
		local function ambient_patch()
			if not allow_ambient or not ambient[id] then return false end
			local vegetation=(h.grass or 0)+(h.flowers or 0)+(h.cover or 0)+(h.canopy or 0)
			local water=(h.water or 0)+(h.near_water or 0)
			return vegetation>0 and (r.medium~="amphibian" or water>0)
		end
		if food then
			for _,v in ipairs(food) do if r.foods[v.food] then return true end end
			if prey_for(probe,p,16) then return true end
			-- A small set of common ambient species may establish in a genuinely
			-- vegetated patch before a modeled feeding transaction is available.
			-- This grants no food or meal credit; all later feeding still requires
			-- the normal shared succession/prey transaction.
			return ambient_patch()
		end
		return #resources(probe,p,time)>0 or prey_for(probe,p,16)~=nil or ambient_patch()
	end
	local function stencil(p)
		-- Existing forage/deposit may mutate the entire 3x3 neighbourhood.
		for x=-1,1 do for z=-1,1 do for y=-1,1 do
			if not node(at(p,x,y,z)) then return false end
		end end end
		return true
	end
	local function move(e,dx,dy,dz)
		local r=records[e.kind]; local p=e.object:get_pos()
		local len=math.sqrt(dx*dx+dy*dy+dz*dz); if len<.001 then stop(e); return false end
		local speed=math.min(r.speed,1.3)
		local b=at(p,dx/len*speed,dy/len*speed,dz/len*speed)
		if not path(p,b,e.kind) or not room(b,e.kind,true,e) then stop(e); return false end
		-- AI thinks every two seconds; retain motion through that interval and
		-- leave a short grace margin so scheduling jitter does not cancel travel.
		e.target={x=dx/len*speed,y=dy/len*speed,z=dz/len*speed}; e.lease=2.5
		local _,mode=safe(p,e.kind)
		animation(e,(mode=="swim" or mode=="fly") and "flight_swim" or "locomotion")
		return true
	end
	-- Songbirds loosely gather around nearby members of their own species.
	-- This is derived from the bounded active-resident set, not a persistent
	-- flock/group assignment; unloaded wildlife retains the same save schema.
	local flocking={robin=true,blackbird=true,blue_tit=true,mallard=true}
	local function flock_direction(e,p,dx,dz)
		if not flocking[e.kind] then return dx,dz end
		local C=hearth.creatura
		if C and type(C.get_boid_dir)=="function" then
			local ok,direction=pcall(C.get_boid_dir,e)
			if ok and valid(direction) then return dx+direction.x*1.35,dz+direction.z*1.35 end
		end
		local count,sx,sz,separate_x,separate_z=0,0,0,0,0
		for other in pairs(active) do
			if other~=e and other.kind==e.kind then
				local q=other.object:get_pos()
				if valid(q) then
					local ox,oz=q.x-p.x,q.z-p.z; local d2=ox*ox+oz*oz
					if d2>0 and d2<=100 then
						count=count+1; sx=sx+q.x; sz=sz+q.z
						if d2<4 then
							separate_x=separate_x-ox/d2; separate_z=separate_z-oz/d2
						end
					end
				end
			end
		end
		if count==0 then return dx,dz end
		local cx,cz=sx/count-p.x,sz/count-p.z
		local distance=math.sqrt(cx*cx+cz*cz)
		if distance>.001 then
			local strength=1.25*math.min(1,distance/6)
			dx=dx*.35+cx/distance*strength; dz=dz*.35+cz/distance*strength
		end
		local separation=math.sqrt(separate_x*separate_x+separate_z*separate_z)
		if separation>.001 then
			dx=dx+separate_x/separation*1.5; dz=dz+separate_z/separation*1.5
		end
		return dx,dz
	end
	local function interaction_player(clicker)
		if type(api.get_connected_players)~="function" or type(hearth.sessions)~="table" then return nil end
		local ok,name=pcall(function() return clicker:get_player_name() end)
		if not ok or type(name)~="string" or #name<1 or #name>64 or not hearth.sessions[name] then return nil end
		local connected_ok,list=pcall(api.get_connected_players)
		if not connected_ok or type(list)~="table" then return nil end
		for _,player in pairs(list) do if player==clicker then return name end end
		return nil
	end
	local function interaction_snapshot(self)
		-- Scalar-only copy: the UI receives no live entity/state table reference.
		local source=self.state
		return {born_at=source.born_at,origin=source.origin,foodreserve=source.foodreserve,
			resident=source.resident_id~=nil,observation=self.clip=="rest" and "rest" or "awake"}
	end
	local function activity_phase(e,time)
		local r=records[e.kind]
		local schedule=r.sleep or {}
		if r.winter_dormant and season(time)=="Winter" then return "sleep" end
		local climate=hearth.climate_at and hearth.climate_at(time)
		local date=os.date("!*t",time)
		local hour=climate and finite(climate.hour) and climate.hour%24 or date.hour
		local elevation=climate and finite(climate.elevation) and climate.elevation
			or (hour>=6 and hour<18 and 1 or -20)
		local activity=r.activity
		if activity=="day" then
			if elevation<=(schedule.sleep_below or -6) then return "sleep" end
			if elevation<(schedule.winddown_below or 6) then return "winddown" end
			return "active"
		elseif activity=="night" then
			if elevation>=(schedule.sleep_above or 6) then return "sleep" end
			if elevation>(schedule.winddown_above or -6) then return "winddown" end
			return "active"
		elseif activity=="crepuscular" then
			local light=schedule.active_between or {-8,8}
			local rest=schedule.rest_hours or {11,15}
			if elevation>=light[1] and elevation<=light[2] and (hour<rest[1] or hour>=rest[2]) then return "active" end
			if elevation>=light[1]-4 and elevation<=light[2]+4 then return "winddown" end
			return "sleep"
		elseif activity=="any" then
			local rest=schedule.rest_hours or {12,14}
			local winddown=schedule.winddown_hours or {11.5,14.5}
			if hour>=rest[1] and hour<rest[2] then return "sleep" end
			if (hour>=winddown[1] and hour<rest[1]) or (hour>=rest[2] and hour<winddown[2]) then return "winddown" end
			return "active"
		end
		-- Unknown activity is deliberately conservative, not permanently awake.
		local light=schedule.active_between or {-8,8}
		local rest=schedule.rest_hours or {11,15}
		if elevation>=light[1] and elevation<=light[2] and (hour<rest[1] or hour>=rest[2]) then return "active" end
		if elevation>=light[1]-4 and elevation<=light[2]+4 then return "winddown" end
		return "sleep"
	end
	local function awake(e,time) return activity_phase(e,time)=="active" end
	-- One bounded 9x9x8 (648-node) terrain query per five active seconds.
	-- Never emerge blocks, scan every species, or retain stale terrain results.
	local function candidate(center)
		patch_cursor=patch_cursor%#offsets+1
		local d=offsets[patch_cursor]; local c=cell(at(center,d[1],0,d[2]))
		if not valid(at(c,-4,-4,-4)) or not valid(at(c,4,3,4)) then return nil end
		local names={"hearth:grass","hearth:soil","hearth:water_source","hearth:water_flowing"}
		local D=hearth.diversity
		for name in pairs(api.registered_nodes or {}) do
			if (D and ((D.is_ground and D.is_ground(name))
				or (D.is_worldgen_flora and D.is_worldgen_flora(name))))
				or legacy_flora({name=name}) then names[#names+1]=name end
		end
		if not api.find_nodes_in_area_under_air then return nil,c end
		recruiting.scans=recruiting.scans+1
		local found=api.find_nodes_in_area_under_air(at(c,-4,-4,-4),at(c,4,3,4),names)
		local candidates={}
		for i=1,math.min(#found,648) do
			local q=found[i]
			if valid(q) then
				local n=node(q)
				local p=n and {x=q.x,y=q.y+(ground(n) and .5 or (water(n) and 0 or -.5)),z=q.z}
				local dx,dz=q.x-center.x,q.z-center.z
				if p and dx*dx+dz*dz>=144 and dx*dx+dz*dz<=576 then candidates[#candidates+1]=p end
			end
		end
		table.sort(candidates,function(a,b)
			if a.x~=b.x then return a.x<b.x end
			if a.z~=b.z then return a.z<b.z end
			return a.y<b.y
		end)
		if #candidates==0 then return nil,c end
		candidate_cursor=candidate_cursor+1
		return candidates[(candidate_cursor-1)%#candidates+1],c
	end
	local function recruit(time)
		local function result(reason)
			recruiting.last_reason=reason
			recruiting.reasons[reason]=(recruiting.reasons[reason] or 0)+1
		end
		local observers=players()
		if #observers==0 then result("no_players"); return end
		recruiting.attempts=recruiting.attempts+1
		if not storage_ok then result("registry_unavailable"); return end
		if total>=GLOBAL then result("global_cap"); return end
		player_cursor=player_cursor%#observers+1
		local center=observers[player_cursor]:get_pos()
		if not valid(center) then result("invalid_player"); return end
		local p,patch=candidate(center)
		if not p and not patch then result("no_surface"); return end
		local k=region_key(p or patch)
		local r=region(k,time,true)
		if not r then result(storage_ok and "region_budget" or "registry_unavailable"); return end
		if #r.members>=FOUNDERS then result("region_seeded"); return end
		if not p then result("no_surface"); return end
		for _,player in ipairs(observers) do
			local q=player:get_pos()
			if valid(q) and dist(p,q)<64 then result("observer_near"); return end
		end
		local anchor=cell(at(p,0,.1,0))
		if not stencil(anchor) then result("blocked_or_unloaded"); return end
		-- Guarded natural-worldgen adoption only; never grant food, edit crops,
		-- or fabricate botanical ages. Succession owns all subsequent debits.
		local D=hearth.diversity
		if D and type(D.bootstrap)=="function" then
			for x=-1,1 do for z=-1,1 do
				local q=at(anchor,x,0,z); local n=node(q)
				local below=at(q,0,-1,0)
				if n and unmarked(q) and unmarked(below) and ground(node(below)) then
					D.bootstrap(q,n)
					-- The legacy three ground sprites predate diversity's catalogue.
					-- Adopt only provenance, never an age/profile or a ration.
					if legacy_flora(n) then api.get_meta(q):set_string("succ_natural","1") end
				end
			end end
		end
		local h=observe_habitat(p)
		if not h then result("habitat_unloaded"); return end
		-- Collect represented plant foods once, then match the catalogue in
		-- rotating order. Failed species do not trigger 23 terrain/food scans.
		local food={}; local seen={}
		for _,id in ipairs(order) do
			for k in pairs(records[id].foods) do seen[k]=true end
		end
		food=resources(nil,p,time,seen)
		local reason="no_active_food_match"
		for i=1,#order do
			local index=(recruit_kind+i-1)%#order+1; local id=order[index]
			if counts[id]<records[id].cap and awake({kind=id},time) and habitat(p,id,time,h,food,false) then
				if not room(p,id,false) then result("population_cap"); return end
				if safe(p,id) then
					recruit_kind=index
					local before=total
					local ok=pcall(api.add_entity,p,"hearth:"..id)
					if ok and total>before then recruiting.successes=recruiting.successes+1; result("admitted")
					else result("activation_rejected") end
					return
				end
				reason="unsafe_body"
			end
		end
		-- When no species has a represented food item, admit at most one small
		-- songbird founder on a loaded natural vegetated patch. This ambient
		-- observation grants no reserve or meal and never bypasses later feeding.
		if reason=="no_active_food_match" then
			for _,id in ipairs({"robin","blackbird","blue_tit"}) do
				local index
				for i,value in ipairs(order) do if value==id then index=i; break end end
				if index and counts[id]<records[id].cap and awake({kind=id},time)
					and habitat(p,id,time,h,nil,true) then
					if not room(p,id,false) then result("population_cap"); return end
					if safe(p,id) then
						recruit_kind=index; local before=total
						local ok=pcall(api.add_entity,p,"hearth:"..id)
						if ok and total>before then recruiting.successes=recruiting.successes+1; result("admitted_ambient")
						else result("activation_rejected") end
						return
					end
					reason="unsafe_body"
				end
			end
		end
		recruit_kind=recruit_kind%#order+1; result(reason)
	end
	local function earned(e,time)
		local s=e.state; s.foodreserve=math.min(1,s.foodreserve+.25); s.last_meal=time
		s.hunger_seconds=0
		s.nextfeed=time+records[e.kind].feed_seconds
		s.dung_pending=e.kind~="bumblebee" and e.kind~="earthworm"
		stop(e,"feed")
	end
	local function feed(e,p,time)
		local s=e.state; if time<s.nextfeed then return false end
		if not stencil(cell(at(p,0,.1,0))) then return false end
		local S=hearth.succession or {}; local r=records[e.kind]
		local prey,d=prey_for(e,p,12)
		if prey then
			local q=prey.object:get_pos()
			if d<=.8*.8 and path(p,q,e.kind) and safe(q,prey.kind) and remove(prey,true) then
				meals=meals+1; earned(e,time); return true
			end
			if move(e,q.x-p.x,q.y-p.y,q.z-p.z) then return true end
		end
		local pursuit,pursuit_distance
		for _,v in ipairs(resources(e,p,time)) do
			local q=v.pos
			if dist(p,q)<=2.25 and stencil(q) then
				local success=false
				if v.food=="nectar" and type(S.pollinate)=="function" then
					-- Shared per-flower lock belongs to succession, not per-bee memory.
					success=S.pollinate(q)==true; if success then pollinations=pollinations+1 end
				elseif v.food=="litter" and type(S.detritivore)=="function" then
					success=S.detritivore(q)==true; if success then detritus=detritus+1 end
				elseif v.food=="fruit" and type(S.frugivore)=="function" then
					success=S.frugivore(q,v.id)==true
				elseif v.food=="seed" and type(S.granivore)=="function" then
					local consumed,cache=S.granivore(q,v.id)
					success=consumed==true
					-- A second, separately debited viable nut is required for caching:
					-- never eat and plant the same seed. No token survives unload.
					if success and cache==v.id and e.kind=="red_squirrel" and (v.id=="hazel" or v.id=="oak") and S.disperse_seed then
						local dest=cell(at(p,1,0,0))
						if stencil(dest) and S.disperse_seed(dest,v.id)==true then dispersals=dispersals+1 end
					end
				elseif v.food=="browse" and type(S.forage)=="function" then
					success=S.forage(q,v.browse_mode or "herbivore")==true; if success then grazed=grazed+1 end
				end
				if success then earned(e,time); return true end
			end
			local d=dist(p,q)
			if (not pursuit_distance or d<pursuit_distance) and d>2.25 then pursuit,pursuit_distance=q,d end
		end
		if pursuit then return move(e,pursuit.x-p.x,0,pursuit.z-p.z) end
		return false
	end
	local spawning
	local function healthy(e,time)
		local s=e.state
		return active[e] and time>=s.last_seen and time>=s.last_meal and s.foodreserve>=.7
			and time-s.last_meal<=records[e.kind].feed_seconds*2
	end
	local function reproduce(e,p,time)
		local s=e.state; local profile=records[e.kind].profile
		if not profile or profile.reproduction_enabled~=true or s.sex~="female" or e.delivering or spawning then return false end
		if s.pregnancy_until>0 then
			if time<s.pregnancy_until or s.foodreserve<.2 or credit<1 or not habitat(p,e.kind,time) then return false end
			-- One child per budgeted attempt, not an unbounded litter loop. Full
			-- caps/habitat delay the SAME deadline and preserve the remainder.
			local destination=at(p,.25,0,.25)
			if not safe(destination,e.kind) or not room(destination,e.kind,false) then return false end
			credit=credit-1; actions=actions+1
			local child=initial(e.kind,time,(s.seed+time+s.litter_delivered+1.0)%2147483647.0)
			child.origin="born"; child.born_at=time; child.foodreserve=.1
			child.parent_seed=s.seed; child.parent_born_at=s.born_at
			child.resident_id,child.founder_region=identity(e.kind,destination,time,false)
			if not child.resident_id then return false end
			local text=encode(child,e.kind,time); if not text then return false end
			-- Reserve before the engine callback; synchronous reentry cannot pay
			-- the same child twice. Acknowledgement handles nil ObjectRef results.
			e.delivering=true
			s.litter_remaining=s.litter_remaining-1; s.litter_delivered=s.litter_delivered+1
			spawning={text=text,id=e.kind,ack=false}
			local ok,obj=pcall(api.add_entity,destination,"hearth:"..e.kind,text)
			local admitted=spawning.ack; spawning=nil; e.delivering=false
			if not admitted then
				s.litter_remaining=s.litter_remaining+1; s.litter_delivered=s.litter_delivered-1
				if ok and obj and obj.remove then obj:remove() end
				return false
			end
			births=births+1; s.foodreserve=math.max(0,s.foodreserve-.1)
			s.last_birth_at=time; s.nextbreed=time+profile.postpartum_days*DAY
			if s.litter_remaining==0 then
				s.pregnancy_until=0; s.conception_at=0; s.litter_total=0; s.litter_delivered=0
			end
			stop(e,"rest"); return true
		end
		if time<s.nextbreed or activity_phase(e,time)~="active" or not healthy(e,time)
			or not F.can_breed(e.kind,s.born_at,time,s.sex,season(time))
			or not habitat(p,e.kind,time) or not room(p,e.kind,false) then return false end
		local mate
		for other in pairs(active) do
			local q=other.object:get_pos(); local o=other.state
			if other~=e and other.kind==e.kind and o.sex=="male" and valid(q) and dist(p,q)<=4
				and activity_phase(other,time)=="active" and healthy(other,time) and time>=o.nextbreed
				and safe(q,other.kind) and habitat(q,other.kind,time)
				and F.can_breed(other.kind,o.born_at,time,o.sex,season(time))
				and (not mate or other.id<mate.id) then mate=other end
		end
		if not mate then return false end
		s.conception_at=time; s.pregnancy_until=time+math.ceil(development(profile).max*DAY)
		s.litter_total=profile.birth_count.min -- conservative sourced count, not guaranteed survival
		s.litter_remaining=s.litter_total; s.litter_delivered=0
		s.foodreserve=s.foodreserve-.2; mate.state.foodreserve=mate.state.foodreserve-.2
		mate.state.nextbreed=time+DAY -- no same-tick unlimited male mating credit
		stop(e,"rest"); return true
	end
	local function dependent(e,p,time)
		local s=e.state; local profile=records[e.kind].profile
		if s.origin~="born" or not profile or not profile.juvenile_days
			or time-s.born_at>=profile.juvenile_days.max*DAY then return false end
		-- Dependent young do not hunt or browse like adults. Bounded maternal
		-- reserve transfer is coarse care accounting, not simulated milk/nests.
		if time>=s.nextfeed then
			for mother in pairs(active) do
				local m=mother.state; local q=mother.object:get_pos()
				if mother.kind==e.kind and m.sex=="female" and m.seed==s.parent_seed and m.born_at==s.parent_born_at
					and valid(q) and dist(p,q)<=4 and safe(q,mother.kind) and m.foodreserve>=.3 then
					m.foodreserve=m.foodreserve-.05; s.foodreserve=math.min(1,s.foodreserve+.05)
					s.last_meal=time; s.hunger_seconds=0; s.nextfeed=time+records[e.kind].feed_seconds; break
				end
			end
		end
		stop(e,"rest"); return true
	end
	local function think(e,time)
		local p=e.object:get_pos()
		local s=e.state
		if time<s.last_seen then stop(e,"rest"); return end
		if not safe(p,e.kind) or #players()==0 then s.last_seen=time; stop(e,"rest"); return end
		-- Energy observes bounded loaded intervals; calendar age remains absolute.
		local elapsed=math.min(60,time-s.last_seen)
		s.foodreserve=math.max(0,s.foodreserve-elapsed/records[e.kind].reserve_seconds)
		s.hunger_seconds=math.min(MAX,s.hunger_seconds+elapsed)
		s.last_seen=time
		local r=records[e.kind]
		if r.starvation_days and s.hunger_seconds>=r.starvation_days*DAY then remove(e,true); return end
		-- Threat response precedes all resting, including winter dormancy. A
		-- sleeping prey animal can still flee/curl when danger enters its radius.
		local danger,best=nil,64 -- eight-node observer/predator flight radius
		for _,player in ipairs(players()) do
			local q=player:get_pos(); if valid(q) and dist(p,q)<best then danger,best=q,dist(p,q) end
		end
		for other in pairs(active) do
			local q=other.object:get_pos()
			if records[other.kind].prey[e.kind] and valid(q) and dist(p,q)<best then danger,best=q,dist(p,q) end
		end
		if danger then
			if e.kind=="hedgehog" then stop(e,"rest") else move(e,p.x-danger.x,0,p.z-danger.z) end
			return
		end
		if dependent(e,p,time) then return end
		if reproduce(e,p,time) then return end
		if activity_phase(e,time)~="active" then stop(e,"rest"); return end
		if s.dung_pending and time-s.last_meal>=3600 then
			s.dung_pending=false; local q=cell(at(p,0,.1,0)); local S=hearth.succession
			if stencil(q) and S and S.deposit and S.deposit(q)==true then dung=dung+1 end
			return
		end
		if feed(e,p,time) then return end
		e.turn=e.turn+1
		if e.turn%3==0 then stop(e); return end
		local d=directions[(e.id+e.turn)%#directions+1]
		local dx,dz=flock_direction(e,p,d[1],d[2])
		local vertical=(r.medium=="fly" and e.turn%5==0) and .25 or 0
		move(e,dx,vertical,dz)
	end
	for _,id in ipairs(order) do
		local r=records[id]; local b=r.bounds
		api.register_entity("hearth:"..id,{
				collisionbox={b.min[1],0,b.min[3],b.max[1],b.max[2],b.max[3]},
				initial_properties={physical=true,collide_with_objects=false,collisionbox={b.min[1],0,b.min[3],b.max[1],b.max[2],b.max[3]},
				visual="mesh",mesh=r.mesh,textures={r.texture},visual_size={x=1,y=1},static_save=true,
				pointable=true,makes_footstep_sound=false,eye_height=r.eye_height},
			on_activate=function(self,data,dtime_s)
				if active[self] then return end
				local time=now(); local p=self.object:get_pos(); local restored=type(data)=="string" and #data>0
				local state=time and restored and decode(data,id,time) or nil
				local newborn=spawning and spawning.id==id and spawning.text==data
				if (data~=nil and type(data)~="string") or not time or (restored and not state) or (not restored and dtime_s and dtime_s~=0)
					or not valid(p) then log("rejected invalid wildlife snapshot or position"); self.object:remove(); return end
				if (not restored or newborn) and (not safe(p,id) or not room(p,id,false)
					or not habitat(p,id,time,nil,nil,not restored)) then
					self.object:remove(); return
				end
				state=state or initial(id,time,(serial+1)%2147483647)
				if restored and state.resident_id and storage_ok and state.resident_id>ledger.counter then
					-- A missing/rolled-back ledger is not permission to reuse IDs.
					fail_storage()
				end
				if not state.resident_id then
					state.resident_id,state.founder_region=identity(id,p,time,not restored)
					-- A storage fault must not erase a validated legacy resident.
					if not restored and not state.resident_id then self.object:remove(); return end
				end
				serial=serial+1; self.id=serial; self.kind=id; self.turn=0
				-- Creatura's bounded boid cache expects these standard entity fields.
				self.name="hearth:"..id; self.max_boids=5; self.tracking_range=10
				self.width=math.max(b.max[1],-b.min[1]); self._movement_data={}
				self.state=state
				if restored then self.state.last_seen=time; self.state.dung_pending=false end
				self.next_ai=clock; self.velocity={x=0,y=0,z=0}; self.target={x=0,y=0,z=0}; self.lease=0
				active[self]=true; counts[id]=counts[id]+1; total=total+1
				if spawning and spawning.id==id and spawning.text==data then spawning.ack=true end
				self.object:set_armor_groups({immortal=1})
				self.object:set_acceleration({x=0,y=0,z=0}) -- guarded horizontal corridors
				stop(self)
			end,
			get_staticdata=function(self)
				local time=now(); if not time or not self.state then return "" end
				return encode(self.state,id,time) or "invalid"
			end,
			on_step=function(self,dt)
				if not active[self] then return end
				local t=delta(dt); if t==0 then return end
				local p=self.object:get_pos()
				if not safe(p,id) or self.lease<=0 then
					stop(self,(self.clip=="feed" or self.clip=="rest") and self.clip or "idle"); return
				end
				local v=self.velocity; local target=self.target; local limit=t*2
				local dx,dy,dz=target.x-v.x,target.y-v.y,target.z-v.z
				local len=math.sqrt(dx*dx+dy*dy+dz*dz); local ratio=len>limit and limit/len or 1
				local nextv={x=v.x+dx*ratio,y=v.y+dy*ratio,z=v.z+dz*ratio}
				local horizon=math.max(.15,t)
				if not path(p,at(p,nextv.x*horizon,nextv.y*horizon,nextv.z*horizon),id) then stop(self); return end
				self.velocity=nextv; self.lease=math.max(0,self.lease-t); self.object:set_velocity(nextv)
				if math.abs(nextv.x)+math.abs(nextv.z)>.001 then
					local yaw=(math.atan2 or math.atan)(-nextv.x,nextv.z); self.object:set_yaw(yaw)
				end
			end,
			on_rightclick=function(self,clicker)
				if not active[self] or not records[self.kind] or not self.state or not interaction_player(clicker) then return end
				local inspect=hearth.inspect_fauna
				if type(inspect)=="function" then pcall(inspect,clicker,self.kind,interaction_snapshot(self)) end
			end,
			on_punch=function(self,puncher)
				-- A hit only triggers the existing flee movement; immortal armor and
				-- the absence of drops/death handlers keep this noncombat.
				if active[self] and puncher then
					local ok,source=pcall(function() return puncher:get_pos() end)
					local p=self.object:get_pos()
					if ok and valid(source) and valid(p) then move(self,p.x-source.x,0,p.z-source.z) end
				end
				return true
			end,on_deactivate=forget,
		})
	end
	-- Use Creatura's well-tested ambient spawn API for small, visible groups.
	-- Every callback still passes Last Hearth's registry, claims, protection,
	-- collision, habitat and per-player/global caps in on_activate.
	local C=hearth.creatura
	if C and type(C.register_abm_spawn)=="function" then
		local group={robin={"hearth:grass","hearth:forest_floor","hearth:podzol"},
			blackbird={"hearth:grass","hearth:forest_floor","hearth:podzol","hearth:alluvium"},
			blue_tit={"hearth:grass","hearth:forest_floor","hearth:podzol"},
			hare={"hearth:grass","hearth:alpine_turf","hearth:alluvium"},
			rabbit={"hearth:grass","hearth:forest_floor","hearth:alluvium"},
			deer={"hearth:grass","hearth:forest_floor","hearth:podzol"},
			roe_deer={"hearth:grass","hearth:forest_floor","hearth:podzol"},
			red_squirrel={"hearth:forest_floor","hearth:podzol"},
			bank_vole={"hearth:grass","hearth:forest_floor","hearth:podzol","hearth:peat"},
			wood_mouse={"hearth:grass","hearth:forest_floor","hearth:podzol","hearth:peat"}}
		for id,nodes in pairs(group) do
			local ok,err=pcall(C.register_abm_spawn,"hearth:"..id,{
				chance=1800,interval=45,min_height=-1,max_height=240,min_light=0,max_light=15,
				min_group=1,max_group=2,spawn_cap=records[id].cap,nodes=nodes,neighbors={"air"},spawn_active=true})
			if not ok then log("Creatura spawn registration failed for "..id..": "..tostring(err)) end
		end
	end
	api.register_globalstep(function(dt)
		local t=delta(dt); if t==0 then return end
		clock=clock+t; credit=math.min(BUDGET,credit+t*BUDGET)
		-- No recruitment credit banks while nobody is observing this world.
		recruitment=#players()>0 and math.min(5,recruitment+t) or 0
		local time=now(); if not time then return end
		local list={}; for e in pairs(active) do list[#list+1]=e end
		table.sort(list,function(a,b) return a.id<b.id end)
		if recruitment>=5 and credit>=1 then
			recruitment=0; credit=credit-1; actions=actions+1
			recruit(time)
		end
		for _=1,#list do
			if credit<1 then break end
			cursor=cursor%#list+1; local e=list[cursor]
			if active[e] and clock>=e.next_ai then
				credit=credit-1; actions=actions+1; e.next_ai=clock+2; think(e,time)
			end
		end
	end)
	return {species="hearth:hare",fauna=F,global_cap=GLOBAL,player_cap=PLAYER,local_cap=LOCAL,ai_budget=BUDGET,
		status=function()
			local c={}; for id,n in pairs(counts) do c[id]=n end
			local diagnostics={interval=5,scan_nodes=648,attempts=recruiting.attempts,
				successes=recruiting.successes,scans=recruiting.scans,last_reason=recruiting.last_reason,reasons={}}
			for k,v in pairs(recruiting.reasons) do diagnostics.reasons[k]=v end
			return {total=total,hare=c.hare,deer=c.deer,fox=c.fox,counts=c,species_count=23,
				residents={storage_ok=storage_ok,regions=region_count,region_limit=REGION_LIMIT,
					region_size=REGION,founders_per_region=FOUNDERS,counter=ledger.counter},
				recruitment=diagnostics,
				global_cap=GLOBAL,player_cap=PLAYER,local_cap=LOCAL,actions=actions,births=births,
				meals=meals,grazed=grazed,dung=dung,deaths=deaths,pollinations=pollinations,dispersals=dispersals,detritus=detritus}
		end}
end