Problème NameError quand je lance mon programme

Bonjour, j'ai un problème sur un de mes projets en python.
Quand je le lance j'ai : "File "projet.py", line 166, in draw_window
for bird in birds:
NameError: name 'birds' is not defined

Voici le code :

import pygame 
import neat
import time 
import os 
import random 
pygame.font.init()

WIN_WIDTH = 500
WIN_HEIGHT = 800

BIRD_IMGS = [pygame.transform.scale2x(pygame.image.load(os.path.join("imgs", "bird1.png"))), pygame.transform.scale2x(pygame.image.load(os.path.join("imgs", "bird2.png"))), pygame.transform.scale2x(pygame.image.load(os.path.join("imgs", "bird3.png")))]
PIPE_IMG = pygame.transform.scale2x(pygame.image.load(os.path.join("imgs", "pipe.png")))
BASE_IMG = pygame.transform.scale2x(pygame.image.load(os.path.join("imgs", "base.png")))
BG_IMG = pygame.transform.scale2x(pygame.image.load(os.path.join("imgs", "bg.png")))
STAT_FONT = pygame.font.SysFont("comicsans", 42)

class Bird:
 IMGS = BIRD_IMGS
 MAX_ROTATION = 25
 ROT_VEL = 20
 ANIMATION_TIME = 5

 def __init__(self, x, y):
  self.x = y
  self.y = y
  self.tilt = 0
  self.tick_count = 0
  self.vel = 0
  self.height = self.y
  self.img_count = 0
  self.img = self.IMGS[0]


 def jump(self):
  self.vel = -10.5
  self.tick_count = 0
  self.height = self.y

 def move(self):
  self.tick_count += 1

  d = self.vel*self.tick_count + 1.5*self.tick_count**2

  if d >= 16:
   d = 16

  if d < 0:
   d -= 2


  self.y = self.y + d


  if d < 0 or self.y < self.height + 50:
   if self.tilt < self.MAX_ROTATION:
    self.tilt = self.MAX_ROTATION
  else:
   if self.tilt > -90:
    self.tilt -= self.ROT_VEL

 def draw(self, win):
  self.img_count +=1 

  if self.img_count < self.ANIMATION_TIME:
   self.img = self.IMGS[0]
  elif self.img_count < self.ANIMATION_TIME*2:
   self.img = self.IMGS[1]
  elif self.img_count < self.ANIMATION_TIME*3:
   self.img = self.IMGS[2]
  elif self.img_count < self.ANIMATION_TIME*4:
   self.img = self.IMGS[1]
  elif self.img_count == self.ANIMATION_TIME*4 + 1:
   self.img = self.IMGS[0]
   self.img_count = 0

  if self.tilt <= -80:
   self.img = self.IMGS[1]
   self.img_count = self.ANIMATION_TIME*2

  rotated_image = pygame.transform.rotate(self.img, self.tilt)
  new_rect = rotated_image.get_rect(center=self.img.get_rect(topleft = (self.x, self.y)).center)
  win.blit(rotated_image, new_rect.topleft)

 def get_mask(self):
  return pygame.mask.from_surface(self.img)

class Pipe:
 GAP = 200
 VEL = 5

 def __init__(self, x):
  self.x = x
  self.height = 0
  self.gap = 100

  self.top = 0
  self.bottom = 0
  self.PIPE_TOP = pygame.transform.flip(PIPE_IMG, False, True)
  self.PIPE_BOTTOM = PIPE_IMG

  self.passed = False 
  self.set_height()

 def set_height(self):
  self.height = random.randrange(50, 450)
  self.top = self.height - self.PIPE_TOP.get_height()
  self.bottom = self.height + self.GAP

 def move(self):
  self.x -= self.VEL

 def draw(self, win):
  win.blit(self.PIPE_TOP, (self.x, self.top))
  win.blit(self.PIPE_BOTTOM, (self.x, self.bottom))

 def collide(self, bird):
  bird_mask = bird.get_mask()
  top_mask = pygame.mask.from_surface(self.PIPE_TOP)
  bottom_mask = pygame.mask.from_surface(self.PIPE_BOTTOM)

  top_offset = (self.x - bird.x, self.top - round(bird.y))
  bottom_offset = (self.x - bird.x, self.bottom - round(bird.y))

  b_point = bird_mask.overlap(bottom_mask, bottom_offset)
  t_point = bird_mask.overlap(top_mask, top_offset)

  if t_point or b_point:
   return True

  return False

class Base:
 VEL = 5
 WIDTH = BASE_IMG.get_width()
 IMG = BASE_IMG

 def __init__(self, y):
  self.y = y
  self.x1 = 0
  self.x2 = self.WIDTH

 def move(self):
  self.x1 -= self.VEL
  self.x2 -= self.VEL

  if self.x1 + self.WIDTH < 0:
   self.x1 = self.x2 + self.WIDTH

  if self.x2 + self.WIDTH < 0:
   self.x2 = self.x1 + self.WIDTH

 def draw(self, win):
  win.blit(self.IMG, (self.x1, self.y))
  win.blit(self.IMG, (self.x2, self.y))

def draw_window(win, bird, pipes, base, score):
 win.blit(BG_IMG, (0,0))

 for pipe in pipes:
  pipe.draw(win)

 text = STAT_FONT.render("Score : " + str(score), 1,(255,255,255))
 win.blit(text, (WIN_WIDTH - 370 - text.get_width(), 10))

 base.draw(win)
 for bird in birds:
  bird.draw(win)

 pygame.display.update()


def main(genomes, config):
 nets = []
 ge = []
 birds = []

 for _, g in genomes:
  net = neat.nn.FeedForwardNetwork.create(g, config)
  nets.append(net)
  birds.append(Bird(230, 350))
  g.fitness = 0
  ge.append(g)


 base = Base(730)
 pipes = [Pipe(700)]
 win = pygame.display.set_mode((WIN_WIDTH, WIN_HEIGHT))
 clock = pygame.time.Clock()

 score = 0

 run = True
 while run:
  clock.tick(30)
  for event in pygame.event.get():
   if event.type == pygame.QUIT:
    run = False
    pygame.quit()
    quit()

  pipe_ind = 0
  if len(birds) > 0:
   if len(pipes) > 1 and birds[0].x > pipes[0].x + pipes[0].PIPE_TOP.get_width():
    pipe_ind = 1
  else:
   run = False
   break

  for x, bird in enumerate(birds):
   bird.move()
   ge[x].fitness += 0.1

   output = nets[x].activate((bird.y, abs(bird.y - pipes[pipe_ind].height), abs(bird.y - pipes[pipe_ind].bottom)))

   if output[0] > 0.5:
    bird.jump()

  add_pipe = False 
  rem = []
  for pipe in pipes:
   for x, bird in enumerate(birds):
    if pipe.collide(bird):
     ge[x].fitness -= 1
     birds.pop(x)
     nets.pop(x)
     ge.pop(x)


    if not pipe.passed and pipe.x < bird.x:
     pipe.passed = True
     add_pipe = True

   if pipe.x + pipe.PIPE_TOP.get_width() < 0:
     rem.append(pipe)
   
   pipe.move()

  if add_pipe:
   score += 1
   for g in ge:
    g.fitness += 5
   pipes.append(Pipe(600))

  for r in rem:
   pipes.remove(r)

  for x, bird in enumerate(birds):
   if bird.y + bird.img.get_height() >= 730 or bird.y < 0:
    birds.pop(x)
    nets.pop(x)
    ge.pop(x)

  base.move()
  draw_window (win, birds, pipes, base, score)


def run(config_path):
 config = neat.config.Config(neat.DefaultGenome, neat.DefaultReproduction,
  neat.DefaultSpeciesSet, neat.DefaultStagnation,
  config_path)

 p = neat.Population(config)

 p.add_reporter(neat.StdOutReporter(True))
 stats = neat.StatisticsReporter()
 p.add_reporter(stats)

 winner = p.run(main,50)

if __name__ == "__main__":
 local_dir = os.path.dirname(__file__)
 config_path = os.path.join(local_dir, 'NeatConfig.txt')
 run(config_path)

Merci de m'aider. Au revoir !