As I was writing my own fanfic (go check out Waterfall if you haven't lol) and I realized I needed to know what prey could be found in each territory. Searching through other guides, nobody has it listed by territory ahhhHhhHh. So here's a guide to prey that can be found in each territory!! I used uk animals for the most part but there are a few mixed in that can't be found uk.

Size is based off of weight and height of the animal. For the most part, anything the size of a cat is large, anything < 6 inches is small, and in between is medium.

FOREST/WOODS TERRITORY
clans such as ThunderClan. prey that hangs out in forests.
most commonly eat mice, squirrels, smaller birds

Woodland Mammals
      - mouse common, small
      - wood mouse very common, small
      - shrew common, small
      - vole common, small
- chipmunk common, small
      - squirrel uncommon, medium-large
      - rabbit rare, large
Birds
      - wren uncommon, small
      - finch common, small
      - thrush common, small
      - sparrow common, small
      - robin common, small
- dipper uncommon, small
      - wagtail uncommon, small
      - dove uncommon, small-medium
      - starling uncommon, small-medium
      - lark uncommon, medium
      - lapwing rare, medium
      - pidgeon uncommon, medium
      - magpie uncommon, medium
      - kestrel very rare, large, danger lvl 2
      - blackbird uncommon, large
      - crow uncommon, medium-xlarge
      - pheasant rare, large-xlarge
      - moorhen/rail very rare, medium-xl
      - owl rare, xlarge, danger lvl 2
      - buzzard very rare, xlarge, danger 3
      - falcon very rare, xlarge, danger lvl3
      - hawk rare, danger lvl 3
      - eagle very rare, danger lvl 3

RIVER TERRITORY
clans such as RiverClan that are built around rivers.
most commonly eat fish and water creatures. amphibians that are less commonly caught will be found in the marsh territory section. river cats do not particularly like woodland creatures, but will eat when river is frozen.
woodland creatures they eat can be found in the forest territory section.

Fish
- carp common, small-large
- bream common, small-medium 
      - dace common, small
      - perch common, small
      - chub common, medium
- smelt common, small
- loach uncommon, medium
- roach uncommon, small
- eel uncommon, medium
- catfish uncommon, medium
- bitterling uncommon, small
- pike rarer, large, danger lvl 1
- zander rare, large, danger lvl 1
Crustacean
- crayfish uncommon, small
Water Mammals
- stoat uncommon, medium, danger lvl 1
- otter rare, large, danger lvl 2
Water Birds
- kingfisher common, small
- red-winged blackbird common, small
- snipe common, medium
- goose common, large
- gadwall common, large
- bittern uncommon, medium-large
- moorhen uncommon, medium
- coot uncommon, medium-large
- curlew uncommon, medium-large
- swan uncommon, xlarge
- pochard uncommon, large
- wigeon uncommon, large
- osprey uncommon, large
- egret rare, large
- crane rare, xxlarge
- heron rare, xlarge-xxlarge

MARSH TERRITORY
clans such as ShadowClan built in marshy pine forests.
most commonly eat amphibians, reptiles, and woodland creatures. this territory is rich with biodiversity, as many animals nest here due to the abundance of smaller creatures and bugs.

Amphibians
- newt common, small
- frog very common, small
- toad very common, small
Reptiles
- lizard common, small
- grass snake uncommon, small
Marsh Birds
- marsh warbler common, small
- snipe common, medium
- twite common, small
- rail common, medium-large
- tern common, medium
- song thrush common, small-medium
- redshank common, medium
- lapwing uncommon, medium
- bittern uncommon, medium-large
- owls rarer, large-xlarge
- egret rarer, large
- crane rarer, xxlarge
Marsh Mammals
- bats very common, small
- mouse common, small
- water vole common, small
- water shrew common, small
- marsh rabbit uncommon, medium-large
- otter rare, large, danger lvl 2
- muskrat rare, large, danger lvl 2

MOORLAND TERRITORY
clans such as WindClan built in open fields.
commonly eat rabbits and other field animals. plagued with many birds of prey, however they can be a food source.

Field Mammals
- rabbit common, medium
      - hare common, medium-large
- field mouse very common, small
- field vole very common, small
      - shrews common, small
      - moles uncommon, medium-large
Field Birds
     - wren common, xsmall
     - linnet common, small
     - skylark uncommon, small
     - whinchat uncommon, small
     - pipit uncommon, small-medium
     - grouse uncommon, medium-large
     - harrier uncommon, medium-large
     - curlew uncommon, medium-large
     - kestrel uncommon, large
     - owl uncommon, large
     - falcon rare, xlarge, danger lvl3
     - hawk rare, xlarge danger lvl 3
     - eagle rare, xlarge danger lvl 3

Obviously this isn't a complete list of all the possible prey animals in a territory. There are many many different types of birds by the river, I'm just trying to give a general pool of edibles in an area.

Also side note, the cats won't necessarily hunt all of the prey listed for their territory. Cats might shy away from hunting larger animals that might cause injury or have low success rates, such as otters, ducks, birds of prey, etc.

Also if you're looking for cat prefixes, any of these animals make good prefixes.