BirdsAndWolves

globals []
breed[trees tree]
breed[birds bird]
breed[snakes snake]
birds-own[countdown movementforce]
snakes-own[countdown]

to setup
  clear-all
  ask patches[
    set pcolor 58
  ]
  create-trees 300
  [
    set shape one-of ["tree"]
    set color green + random 5
    set size 2
    setxy random-xcor random-ycor
  ]

  create-birds 20
  [
   set shape "butterfly"
   set color one-of base-colors
   set size 1
   setxy random-xcor random-ycor
   set countdown random 10
   set movementforce random 10
  ]

  create-snakes 1
  [
    set shape "wolf"
    set color brown
    set size 2.5
    setxy random-xcor random-ycor
    set countdown random 10
  ]
end 

to go
 ask birds [
  ifelse countdown = 0
    [ ifelse movementforce > 0 [
      move-birds
      set movementforce movementforce - 1
      ]
      [set countdown random 150
      set movementforce random 50 ]
    ]

    [set countdown countdown - 1]
  ]
  ask snakes [
    ifelse countdown = 0[
     move-snakes
    ]
    [set countdown countdown - 1]
    kill-birds
  ]
end 

to move-birds
  rt random 50
  lt random 50
  fd 0.2
end 

to move-snakes
  rt random 5
  lt random 5
  fd 0.09
end 

to kill-birds
  let prey one-of birds-here
  if prey != nobody[
    ask prey [die]
    set countdown 100
  ]
end